1: A Century of Brachytherapy (From the Prostate’s Perspective)
Brachytherapy has played a major role in the treatment of cancer, and its history could easily fill a volume; it would be inappropriate to attempt to compress it into a single chapter. I have endeavored, instead, to chronicle the story of prostate brachytherapy, which is reflective of the history of brachytherapy as a whole.
Brachytherapy: The Prequel
As the discovery of X-rays and radioactivity has been exhaustively recounted (1,2), only a brief synopsis is attempted here. Wilhelm Röntgen, professor and director of the Physical Institute at the University of Würzburg, discovered in 1985 previously undescribed rays exiting a cathode-ray tube.a Within months of his discovery of the unknown (“X”) rays, they were being used for medical diagnosis and therapy.
Technically, radiotherapy preceded the discovery of X-rays. Danish physician Nils Finsen demonstrated in the 1890s that lupus vulgaris (tubercular skin lesions) could be eradicated by ultraviolet (
Source: From Ref. (3). Bie V. Remarks on Finsen’s phototherapy. Br Med J. 1899;2(2022):825−830.
Antoine Henri Becquerel discovered that uranium spontaneously emitted rays similar to Röntgen rays (1896). In 1898, graduate student Marie Sklodowska Curie identified polonium and radium, two radioactive elements present in minute quantities in uranium ore. Radium seemed to emit an inexhaustible supply of energy, and engendered an entirely new frontier in physics (8). Although radium rays were soon found to have biological properties similar to those of X-rays (the first reported radium cancer cure was in 1903 [9]), its scarcity rendered it almost unobtainable by clinicians. While X-ray tubes were cheap, radium was the most precious material on Earth (10).c The widespread practice of brachyradiumd could not become established until the element became more plentiful.
The Radium Industry
The richest known deposit of uranium ore during the first two decades of the 20th century was in St. Joachimsthal (the St. Joachim Valley) in Bohemia (now Jachymov, in the Czech Republic). St. Joachimsthal’s mineral riches had been exploited for centuries; so much silver was taken from the valley that the Austro-Hungarian Empire established a mint there.e Its miners had long been known to succumb to Bergkrankheit (mountain sickness); it would be centuries before the illness was identified as lung cancer, caused by the inhalation of radioactive dust and gas (11).
Although pitchblende ore is almost 50% uranium, radium makes up only about one part per million. Tons of uranium ore were processed (through a painstaking process of chemical reactions and fractional crystallizations) to obtain a single gram of radium. Several European firms (Chininfabrik Braunschweig in Germany; Armet De Lisle and the Société Centrales des Produits Chimiques in France) produced radium commercially. The cost of radium rose after the Austro-Hungarian government restricted the export of pitchblende, and the situation worsened with the outbreak of the First World War. German physicians sought a substitute in mesothorium (a mixture of 228Ra and 228Ac), the decay product of thorium.f The French discovered radium in the American West; southwestern Colorado and southeastern Utah have deposits of carnotite, a uranium/vanadium ore (13). Although comparatively radium poor (it is only about 2% uranium), carnotite was the best available source. The ore was brought by rail to Buffalo,
Large-scale American production of radium began with the Standard Chemical Company of Pittsburgh, in 1913. Brothers Joseph and James Flannery (who were originally undertakers) had become wealthy producing vanadium for strengthening steel.g The Flannerys’ interest turned to radium after they were unable to obtain the substance in the United States for treatment of a cancer-stricken relative. When they learned that the carnotite that they had been mining in Colorado contained traces of radium, they shipped the ore to a reduction mill south of Pittsburgh for radium extraction.h Within a few years, Standard Chemical produced more than half the world’s radium (Figure 1.2). Rich uranium deposits were discovered in the Katanga province of Belgium’s Congo colony in 1915, but were not mined until after the war. The Belgians, exploiting the Congo’s rich ore and native labor, were able to halve the cost of radium, eliminating American competition.i The cost was further reduced a decade later, when rich pitchblende deposits were discovered in the Canadian Northwest Territories.
Source: Photograph courtesy of the National Institute of Standards and Technology.
The Era of Intracavitary Radium Therapy
Prostate cancer was rarely diagnosed a century ago, but prostatitis, benign hyperplasia, and even tuberculosis of the prostate were treated by X-irradiation (15,16). Successful treatment of prostate cancer by X-rays was first reported in France in 1904 (17). Treatment of prostatic disease with radium was first reported in Paris, at a meeting of the Assoçiation Francaise d’Urologie in October 1909 (18). Ernst-Louis Desnos treated hypertrophy with a series of urethral and rectal applications (19). Henri Minet treated cancers of the prostate, bladder, and ureter with a silver tube containing 10 mg of radium, applied through a urethral catheter or a suprapubic cystotomy (20). Urologist Octave Pasteau and radium therapist Paul-Marie Degrais also began treating prostate cancer with intracavitary radium in 1909, but their first reports did not appear for several years (21). Pasteau’s rationale for preferring brachytherapy to prostatectomy was that “in cancer of the prostate the curative treatment by operation is in truth illusory; it is dangerous, and gives the most temporary results,” whereas these tumors are “particularly susceptible to the influence of radium” (22). They had used a silver capsule, containing 10 to 50 mg of radium sulfate, placed near the tip of a 17Fr coudé urinary catheter (Figure 1.3). Five treatment sessions, each lasting 2 to 3 hours, were delivered over 2 weeks. The series could be repeated periodically (annual maintenance treatments were prescribed for patients who had enjoyed a complete response). Desnos, Minet, and Degrais (who coauthored the first comprehensive radium therapy text in 1909 [23]) understood the need to filter caustic beta particles and soft gamma rays with a radiodense capsule, and that bremsstrahlung radiation (arising from the capsule) should be filtered by less dense material (rubber tubing).
Source: From Ref. (21). Public domain, from Pasteau O, Degrais. De l’emploi du radium dans le traitement des cancers de la prostate (The use of radium in the treatment of prostate cancer). J Urologie Med Chirur. 1913;4:341–366.
Prostate brachytherapy was performed in Vienna in 1909 (24). Rudolf Paschkis and Wilhelm Tittinger reported the case of a 32-year-old man treated with radium at the Rothschild Hospital. The patient had been admitted for urinary retention, and digital examination suggested locally advanced, unresectable cancer of the prostate. A catheter could not be passed, so cystotomy was performed, exposing a nodular, ulcerating tumor infiltrating the bladder neck. The tumor was treated with a capsule containing 4.7 mg of radium bromide applied through the bladder fistula. Treatments lasted 20 minutes and were repeated at 2 week intervals. After 10 months of treatment, the tumor had vanished and the patient was voiding through his urethra. The case was the first to have pathologically confirmed malignancy prior to treatment, and complete clinical response following it (25).
Although Hugh Hampton Young introduced his radical prostatectomy procedure for cancer in 1904 (26), he rarely performed it, as it was uncommon for patients to be diagnosed with organ-confined disease (27). Young had attended the International Congress of Medicine in London in 1913, where he heard Pasteau and Degrais present their experience with radium therapy. He acquired 102 mg of radium and developed his own system of delivering treatment through the rectum, urethra, and bladder, as well as by applying external radium placques (essentially “crossfiring” the tumor). A single application site was treated in a daily “seance” (treatment session) lasting 1 to 2 hours. Treatment sites were alternated and carefully mapped (Figure 1.4), so that no mucosal segment was irradiated twice; in this way, urethritis, cystitis, and proctitis were avoided (28). A typical course of treatment delivered 3,000 to 4,000 mg h of radium therapy. Results were gratifying; Young reported “amazing resorption of extensive carcinomatous involvement of prostate and seminal vesicles” resulting in the “disappearance of pain and obstruction . . . which is indeed remarkable” (29). He treated 500 patients with radium therapy between 1915 and 1927 (30), and his textbook of urology devoted many more pages to radium therapy than to radical prostatectomy (28).
Source: From Ref. (28). Young HH. Treatment of carcinoma of the prostate. In: Young HH, Davis DM, eds. Young’s Practice of Urology: Based on a Study of 12,500 Cases. Vol 1. 1st ed. Philadelphia, PA: WB Saunders; 1926:644–671. Used with permission.
The Era of Interstitial Radon
James Douglas, a Canadian-American mining engineer and executive, became interested in radium after losing a daughter to breast cancer. He was appalled that she had to travel to Europe to be treated with radium that had been mined in the United States. He joined with surgeon Howard Kelly (America’s leading gynecologist, one of Johns Hopkins Medical School’s “Big Four”) in lobbying Congress to nationalize American radium-bearing lands. When Congress declined to do so, Kelly and Douglas entered into a collaborative effort with the United States Bureau of Mines. They established the National Radium Institute in 1913, with Kelly and Douglas providing the capital and the Bureau supplying the mining and processing expertise. The institute leased 16 carnotite claims in Colorado’s Paradox Valley for 3 years. The ore was transported, by burro and rail, to their processing plant in Denver. Operations ceased in 1917, after 8.5 g of radium was refined. One-half gram was donated to government hospitals, and the remaining radium was divided between Kelly and Douglas. Douglas donated his 4 g to New York’s Memorial Hospital, with the stipulation that the hospital become dedicated to the treatment of cancer (31).j
Radium’s specific activity (ratio of activity to mass) is low, due to its long half-life (1,600 years). In practical terms, it takes at least a week to deliver a curative dose with radium needles. This would be particularly awkward for the treatment of prostate cancer, as the sources would be left in an open suprapubic or perineal wound for an extended period (32). The solution to this problem lies in radon, radium’s first daughter product (Table 1.1). As most of the therapeutic gamma rays exiting a radium tube were actually emitted by daughter product “radium C” (214Bi), radium (226Ra) itself was unnecessary for “radium therapy.” Treatment with radium C would be challenging, due to its 20 minute half-life, but radon (known as radium emanation until 1923) could serve as a reservoir for radium C. Radon has a very high specific activity, owing to its short (3.8 day) half-life; despite being a gas, 1 Ci of radon has a volume of less than 1 mm3. Because of its high specific activity, an “emanation” needle could be much thinner than a radium needle. Consequently, radium salts were kept in an aqueous solution, and the emitted radon gas was harvested for therapeutic applications. Unfortunately, the collected gas was mostly composed of water vapor, hydrogen and oxygen (from electrolysis of the water), helium (from alpha particles), and chlorine (from the hydrochloric acid used to keep the radium ions in solution). Harvard biophysicist William Duane had spent 7 years as a research associate of the Curies, much of that time focusing on the purification of radon. On his return to the United States, he built a radium emanation plant at Boston’s Collis P. Huntington Hospital, which he replicated at Memorial Hospital (33,34). Memorial’s entire 4 g of radium was kept in solution (Figure 1.5), and the purified radon was encapsulated in short lengths of glass capillary tubes, 0.3 mm in diameter (Figure 1.6), which were inserted into hypodermic needles. The radon-bearing needles were used for temporary implantation (the needles’ steel filtered most beta particles and soft gamma rays).
Source: From Ref. (33). Failla G. The physics of radium. In: Clark JG, Norris CC, eds. Radium in Gynecology. Philadelphia, PA: JB Lippincott Co; 1927:63. Used with permission.
Old Name | Symbol/Isotope | Half-Life | Emissions |
---|---|---|---|
Radium | 226 Ra | 1,600 y | α |
Radium Emanation | 222 Rn | 3.8 d | α |
Radium A | 218 Po | 3 min | α |
Radium B | 214 Pb | 27 min | β γ 0.3 MeV |
Radium C | 214 Bi | 20 min | β γ 0.3–2.3 MeV |
Radium C’ Radium C’’ | 214 Po 210 Ti | 0.16 ms 1.3 min | α β |
Radium D | 210 Pb | 22 y | β γ |
Radium E | 210 Bi | 5 d | β |
Radium F | 210 Po | 138 d | α |
Lead | 206 Pb | Stable |
Beginning in 1915, Memorial’s urologist, Benjamin Barringer, used these needles for outpatient treatment of prostate cancer (35). With the patient in the lithotomy position, Barringer anesthetized the perineum prior to implanting a 15 cm needle, under the guidance of a finger in the rectum, into a lateral prostate lobe. The needle, bearing 50 to 100 mCi of radon in its distal 3 cm, was left in place for 4 to 6 hours before being retracted and inserted into the other lateral lobe. The seminal vesicles were often treated through a transrectal puncture. Treatments were repeated as necessary, at intervals of several months (36). Barringer reported highly favorable tumor responses.
With abundant quantities of short half-life radon, it became appealing to perform permanent implants. At first, “bare” glass tubes were implanted into tumors, but this practice resulted in painful sloughing of necrotic tissue. Memorial’s physicist, Gioacchino Failla, recognized the offender to be unfiltered caustic beta particles. He remedied the problem by encasing the radon in a 0.3 mm thick envelope of gold (Figure 1.7) that filtered out 99% of beta particles while allowing more than 80% of therapeutic gamma rays to pass (37). Barringer implanted up to 20 seeds, each containing 1.5 to 2.0 mCi of radon, into the prostate, typically delivering 4,000 mCi h of treatment (38). Barringer’s techniques were adopted at other institutions (39,40), and a “gold” radon seed industry was established that persisted in the United States for decades (41).k
Introduction of Man-Made Radionuclides
The large majority of prostate cancer patients undergoing radium or radon brachytherapy developed recurrence (38). This is not surprising, as most men diagnosed in that era had advanced disease that could not be cured by any means. The use of prostate brachytherapy waned after Charles Huggins (1901–1997) discovered that prostate cancer responds to androgen deprivation (1941) (42), but interest revived on recognition that castration was only temporarily effective.
Congress passed the Atomic Energy Act after World War II, establishing the Atomic Energy Commission. The Oak Ridge Laboratories were transferred to civilian control and directed to provide radioisotopes for peaceful purposes, including medical applications. One of the first radionuclides made available was radiogold (Au-198); its short half-life (2.7 days) is comparable to that of radon, but is safer to handle because it does not generate megavoltage photons and has no radioactive daughter products. Microparticles of forming a colloid for instillation into pleural or peritoneal cavities (to suppress malignant effusions and ascites) (43), or injected into lymphomatous masses and solid tumors (44). The first radiogold prostate implant, at the University of Iowa in 1951, was unplanned (45). The prostate of an 80-year-old man with hormone-refractory Stage C disease was surgically exposed for radon seed implantation, but the seeds were not available. Colloidal gold was at hand, and was infiltrated into the prostate. The treatment was without apparent toxicity, the bulky tumor resolved, and follow-up biopsy was negative (46). The urologist, Rubin Flocks, began infiltrating colloidal gold into the prostate and seminal vesicles of men with Stage C disease, through suprapubic and perineal approaches. An enthusiastic report on 20 cases was published in the Journal of Urology the following year (47).
There were compelling reasons to consider colloidal gold as a suitable radionuclide for prostate brachytherapy. It is a beta emitter that deposits 90% of its energy within millimeters (it was assumed that the fascia investing the prostate and seminal vesicles would limit the colloid’s migration). There was evidence that gold microparticles would be phagocytosed by macrophages, which, on circulating to draining lymph nodes, would irradiate D1 metastases (48). In reality, treatment did not work as expected. Dense tumor nodules resisted infiltration; the colloid had to be injected under pressure, resulting in spattering that contaminated drapes, scrubs, and shoes (Figure 1.8). Radiation exposure to personnel was so high that surgical teams were rotated to avoid accumulation of prohibitive doses (49). Much of the injected material leaked out of the prostate, pooling in the pararectal gutters, causing severe rectal injury (50). Some of the gold microparticles entered the circulation, and autoradiographs demonstrated hepatic accumulation. Although radiogold did percolate through regional lymphatics, it did not penetrate tumor-congested nodes (50). Flocks devised several maneuvers to overcome these difficulties: Grossly abnormal lymph nodes were resected; hyaluronidase and epinephrine were mixed into the colloid to improve distribution and reduce vascular uptake; and small volumes of highly concentrated suspension were used to reduce leakage from the gland (49). It became apparent that the procedure was only effective for the smallest tumors (50), and 80% of posttreatment biopsies were positive (51). Flocks eventually resorted to perineal prostatectomy, using radiogold as adjuvant therapy (infiltrating the colloid into periprostatic fascia and vascular pedicles) (46). He defended the procedure, claiming better local control (95%) for Stage C disease, compared to published prostatectomy series (70%–80%) (52). Toxicity, however, was significant: delayed healing in 80% and “persistent urethro-cutaneous fistula” in 2% (53). Use of colloidal gold continued at the University of Iowa Hospitals until its manufacture ceased in 1977; thereupon, radiogold grains were substituted.
Source: From Ref. (49). Flocks RH, Culp DA. Radiation Therapy of Early Prostate Cancer. Springfield, IL: Charles C. Thomas; 1960. Public domain.
Urologist C. Eugene Carlton (1930−) initiated a prostate brachytherapy program at Baylor Hospital in 1965. He chose to implant Au-198 grains (rather than colloid) because of ease of handling and more accurate placement. The procedure began with lymph node dissection, followed by incision of the endopelvic fascia and mobilization of the prostate, allowing implantation under direct visualization (54). Initially, a single gold grain was implanted in the tumor nodule; eventually, the procedure entailed implantation of 6 to 10 grains, distributed within the gland (55) (Figure 1.9). Cobalt (later, linac) teletherapy began 2 to 3 weeks later; the radio-opaque grains served as fiducial markers, identifying the prostate. Although the procedure was designed for Stage C disease, early results were so promising (58% negative biopsies) that it was also used to treat patients with organ-confined disease (54). Toxicity consisted mostly of thrombophlebitis and temporary extremity or genital edema (secondary to the node dissection). The incidence of proctitis was 16%, but less than 1% of patients required colostomy (56). Impotence was reported to develop in only 5% of men who were potent prior to treatment. The procedure became so popular that many private urologists at affiliated hospitals participated. But the Baylor program had serious flaws. The radiogold grains were delivered to Baylor once weekly, and their activity at time of implantation varied widely (between 2 and 9 mCi, depending on the day of implantation). Dosimetry was crude; dose was estimated by assuming that the entire implant activity was deposited at the geometrical center of the prostate, and the delivered dose was defined as the isodose that subtended a diameter equivalent to that of the gland (56). It is difficult to encompass the gland with so few sources, even if they were well placed. Years later, formal dosimetric evaluation demonstrated that these implants typically delivered less than a third of the prescribed dose (57). It is not surprising that, with longer follow-up, treatment outcomes were disappointing (58,59).
Source: From Ref. (55). Hudgins PT. Irradiation of prostatic cancer combined with abdominal exploration. In: Fletcher GH, ed. Textbook of Radiotherapy, 2nd ed. Philadelphia, PA: Lea & Febiger; 1975:768–772. Used with permission.
Ulrich K. Henschke (1914–1980) came to New York to head Memorial’s brachytherapy service in 1955. He had spent the previous 3 years at Ohio State University, where he collaborated with William Myers in the introduction of Au-198 and Ir-192 into clinical practice (60,61). In New York, however, most of his permanent implants used radon, because the daily seed requirement was unpredictable (he was called to the operating room whenever a surgically exposed tumor was found to be unresectable) (62) and large quantities of radon seeds were produced by Memorial’s radon plant. In 1963, health physicist Donald Lawrence sought funding from Memorial for production of an I-125-impregnated suture (63). Henschke provided encouragement and modest financial support, but advised that the radionuclide be encapsulated in a seed.l Within months, Lawrence sent him iodine seeds for animal studies, and Henschke began performing human I-125 implants for lung cancer in 1965 (64). Henschke’s protégé, Basil Hilaris (1928−), assumed leadership of the brachytherapy service upon Henschke’s departure in 1967. Brachytherapy had been used at Memorial as salvage therapy for locally recurrent prostate cancer (following failed radiation or hormonal therapy) since 1956 (65), and Hilaris proposed I-125 prostate brachytherapy as primary treatment to Memorial’s chief of urology, Willet Whitmore, Jr. (1917–1995). Whitmore was receptive; he had attempted aggressive surgical resections early in his career, but by 1963 (66), acknowledged the futility of radical prostatectomy to control locally advanced disease. He concluded that intervention for prostate cancer should consider quality of life, and “need not necessarily involve an effort at cancer cure” (67).
Memorial’s I-125 implant procedure began with the patient in a modified lithotomy position (68). A Foley catheter was inserted and an O’Connor drape (with an appendage allowing insertion of a finger into the rectum) was placed. A midline or paramedian incision extended from the umbilicus to the pubis. External, hypogastric, and obturator nodes were dissected. Fat was removed from the anterior surface of the prostate, but the puboprostatic ligaments were left intact. The endopelvic fascia was incised, mobilizing the lateral margins of the gland, but the prostate was not dissected from the rectum (69). The radiation therapist then inserted empty 15 cm long 16-gauge steel needles into the gland, spaced approximately 1 cm apart. The needles were slowly advanced until sensed by a finger in the rectum (Figure 1.10). Gland dimensions, measured intraoperatively, were used to calculate prostate volume, which determined total implant activity. The number of seeds needed for the implant was derived by dividing the calculated total implant activity by the activity of the available seeds (the ideal seed strength was eventually determined to be 0.5 mCi). Memorial physicist Lowell Anderson developed nomograms to rapidly calculate seed requirements and spacing (70). An applicator was developed to implant the seeds (71) (Figure 1.11). Bleeding could be heavy (median blood loss was 1 L), and almost half the patients required transfusion (72). The Foley catheter was removed 1 to 3 days postoperatively, and the patient was discharged a week later. Postoperative irradiation was delivered to patients found to have lymphatic metastases or bulky tumors (73). Operative mortality was rare (0.5%). The most distressing complications (venous thrombosis, pulmonary embolism, lymphocele, lymphedema) were attributed to lymph node dissection. Impotence or incontinence occurred in fewer than 10% of cases (72).
Source: From Ref. (67). Whitmore WF Jr. Proceedings: the natural history of prostatic cancer. Cancer. 1973;32(5):1104–1112. © 1975 Memorial Sloan-Kettering Cancer Center. Used with permission.
Source: From Ref. (71). Hilaris BS. A Manual for Brachytherapy. 2nd ed. New York, NY: Memorial Hospital; 1970:65. © 1970 Memorial Sloan-Kettering Cancer Center. Used with permission.
A computer program was used to calculate dose distribution from postimplant radiographs (see the “Computer Dosimetry” section; Figure 1.12). Without accurate delineation of the target volume, however, the adequacy of an implant was difficult to determine. The dose covered by a volume equivalent to that of the prostate (calculated from intraoperative measurements) was deemed the “matched peripheral dose” (
Source: From Ref. (68). Hilaris BS, Whitmore WF, Batata M, et al. Cancer of the prostate. In: Hilaris BS, ed. Handbook of Interstitial Brachytherapy. Acton, MA: Publishing Science Group; 1975:219–234. © 1975 Memorial Sloan-Kettering Cancer Center. Used with permission.
Source: From Ref. (68). Hilaris BS, Whitmore WF, Batata M, et al. Cancer of the prostate. In: Hilaris BS, ed. Handbook of Interstitial Brachytherapy. Acton, MA: Publishing Science Group; 1975:219–234. © 1975 Memorial Sloan-Kettering Cancer Center. Used with permission.
More than a thousand patients were implanted with iodine seeds at Memorial Hospital between 1970 and 1986. It was appreciated that quality implants controlled very early disease, but few patients had presented with early disease, and few implants delivered the prescription dose. Disease-free survival curves never plateaued (77), and reports of disappointing long-term control rates (78,79) led to abandonment of the procedure.
Return of the Transperineal Approach and Introduction of Image Guidance
The template, a simple device that directed the distribution of implanted sources, appeared by mid-century (80). It improved implant quality by maintaining source spacing and parallelism (Figure 1.14) (81).
Source: From Ref. (81). Green A. New techniques in radium and radon therapy. J Fac Radiol. 1951;2(3):206–223.
Beginning in 1971, University of Miami radiation oncologist Komanduri Charyulu (1924−) performed “closed” implants on patients with disease too advanced for the standard “Memorial” technique (82). With the patient in the lithotomy position, he passed needles through a handheld template positioned against the perineum. The template could be angled to overcome pubic arch interference. Needles were advanced, under fluoroscopic guidance, up to the contrast-filled bladder. He could not, of course, visualize the prostate by fluoroscopy, but his object was to encompass the region of the prostate with a matrix of seeds, 4 cm wide, 4 cm high, and 5 cm deep (Figure 1.15). Charyulu’s plan utilized three strengths of radon seeds (0.15, 1.0, and 0.8 mCi) in a Paterson−Parker distribution, to achieve a relatively homogeneous dose distribution. Charyulu’s transperineal patients enjoyed superior local control, without surgical complications, compared to patients with earlier disease that he had treated with the Memorial “open” retropubic technique.
Source: From Ref. (82). Charyulu KKN. Transperineal interstitial implantation of prostate cancer: a new method. Int J Radiat Oncol Biol Phys. 1980;6:1261–1266.
At the University of Nebraska in 1979, Pradeep Kumar began implanting I-125 seeds transperineally (83). The seed requirement (to achieve a minimal prostate dose of 160 Gy) was estimated preoperatively from a
Memorial Sloan-Kettering brachytherapists transitioned from “open” retropubic implants to transperineal implants in the 1980s. Patients underwent a planning
Source: From Ref. (90). Nori D, Donath D, Hilaris BS, et al. Precision transperineal brachytherapy in the treatment of early prostate cancer. Endocuriether Hypertherm Oncol. 1990;6:119–130. Used with permission of
The Incorporation of Sonography
Physicists involved in the discovery of radium also uncovered the principles underlying sonography. The piezoelectric effect (the property of certain crystals to develop an electric potential when mechanically stressed) was described in 1880 by Marie Curie’s future husband (Pierre, 1859–1906) and brother-in-law (Jacques, 1856–1941). The following year, Marie Curie’s thesis adviser (Jonas Gabriel Lippmann, 1845–1921) predicted that a change in electric potential would alter a crystal’s dimensions (91). These phenomena underlie the function of the ultrasound transducer: The generation and detection of sound waves. The first practical application of sonography was a device to detect German U-boats (sonar), patented in 1916 by Pierre Curie’s doctoral student (Paul Langevin, 1872−1946m). Sonography was later used by industry as a nondestructive method for detecting metal flaws and fatigue (replacing X-rays and gamma rays for that purpose) (92). Ultrasound was applied by physiatrists in the 1930s to therapeutically heat subsurface tissues (93). Diagnostic applications were developed in the late 1940s; initial attempts measured the transmission of ultrasound waves through tissue (hyperphonography) (94), but detection of reflected waves was investigated by 1950 (95). Sonography for detection of cancer was described in 1957 (96).
An inventive and mechanically inclined Danish surgical resident, Hans Henrik Holm (1931−), became interested in sonography during a radiology rotation. He visited physicist Carl Hellmuth Hertzn (1920–1990) in Lund, Sweden. Hertz had explored medical applications of sonography with cardiologist Inge Edler (“father of echocardiography,” 1911–2001) and neurosurgeon Lars Leksell (“father of radiosurgery,” 1907–1986). Holm was awarded a state grant to obtain an ultrasound unit, and duplicated Lund’s multidisciplinary methodology by collaborating with a cadre of young physicians, as well as with the Welding Institute (a state technology laboratory) to adapt and develop ultrasound apparatus for clinical use.o Equipment was designed to be mobile, so that bedside procedures could be performed. The group developed techniques for interventional sonography in the 1970s, including percutaneous biopsy, drainage, pericardiocentesis, amniotic fluid sampling, and percutaneous nephrostomy.
In 1974, the Welding Institute introduced a probe with transducers for transurethral and transrectal imaging (97,98). A “fixing sledge” (stepper unit) that retracted the probe at 5 mm intervals facilitated planimetric volume determinations (98). A metal template mounted on the probe shaft directed prostate and seminal vesicle biopsy (99). By 1980, Holm was using ultrasound guidance to implant I-125 seeds (separated by chromic suture spacers) into liver metastases and pancreas tumors (100,101). The prescription dose was 160 Gy, and most patients also underwent adjuvant teletherapy. By 1982, he was implanting I-125 seeds into cancerous prostates, under the direction of axial imaging from a rectal probe mounted on a sledge-stepper (102). Preplanning and implantation were performed with the patient in the lithotomy position. A modified Memorial Hospital nomogram determined the implant activity needed to deliver 160 Gy, based on Henschke’s system of dimension averaging (103). A 3 cm thick acrylic template was attached to the probe shaft (Figure 1.17). After immobilizing the gland with an empty needle passed through the template, needles preloaded with seeds and spacers were inserted. Needles that were to be advanced most deeply (in the central gland) were placed first. After proper needle position was confirmed by transverse sonographic imaging, the seeds were deposited by stabilizing the stylet while the needle was retracted. The ultrasound probe was then retracted 5 mm, and the next deepest set of needles was placed; in this fashion, concentric circles of needles were inserted and their seeds deposited. Postimplant dosimetry was performed on orthogonal radiographs the following day (Figure 1.18).
Source: From Ref. (105). Holm HH. The history of interstitial brachytherapy of prostatic cancer. Semin Surg Oncol. 1997;13(6):431–437.
Source: From Ref. (116). Torp-Pedersen S, Holm HH, Littrup PJ. Transperineal I-125 seed implantation in prostate cancer guided by transrectal ultrasound. In: Lee F, McLeary RD, eds. The Use of Transrectal Ultrasound in the Diagnosis and Management of Prostate Cancer. New York, NY: Alan R Liss; 1987:151.
A 1989 paper reported that 33 patients had undergone implantation followed by teletherapy (40–47.4 Gy in 20 fractions) with as little as a 2 week interval between brachytherapy and teletherapy (106). Of 25 patients undergoing postimplant biopsy and/or transurethral resection, 12 had pathological evidence of persistent disease. Forty-five percent of patients had suffered “severe” late complications (hemorrhagic proctitis, anal ulceration, rectovesical fistula, or “severe persisting radiation cystitis”). The combination of disappointing disease control and high morbidity led to abandonment of the program in 1987 (107).
By then, several centers in Europe (108–111) and the United States had adopted Holm’s technique. Stefan Loening, at the University of Iowa, visited Holm in 1984 and began performing ultrasound and fluoroscopically guided transperineal implants in October (112). His technique differed from Holm’s in that he used a Mick applicator to implant Au-198 grains under axial and sagittal ultrasound imaging (113). One hundred seventy-nine patients were implanted in Iowa within 7 years (114). Patients with bulky tumors were treated with a combination of brachytherapy and teletherapy (115). Response was monitored by digital examination, prostate shrinkage on serial sonography, and biopsy. Roughly half of the 12 month biopsies were positive, but some became negative at 24 or 36 months (115). Toxicity was modest.p
After visiting Holm in 1984, Seattle urologist Haakon Ragde (1927−) proposed the institution of an ultrasound-directed brachytherapy program to radiation oncologist John Blasko (1943−). Blasko had reservations; the recently introduced prostate specific antigen (
They used Brüel and Kjær (B&K) equipment (Figure 1.19). Implantation was preceded by a volume study, acquiring axial images separated by 0.5 cm. Their target volume was several millimeters wider than the prostate. The treatment plan consisted of placing seeds 1.0 cm apart (the holes on their original template were separated by 1.0 cm) throughout the target volume (placing some seeds in extracapsular locations). The total implant activity was determined by nomogram (initially, Holm’s nomogram [117]; later a modification of the Memorial nomogram [118]), and individual seed strength calculated by dividing total implant activity by the number of seeds in the plan. Computer dosimetry checked the adequacy of the preplan. Eighty to hundred seeds, of 0.30 to 0.40 mCi, were implanted. The seeds (separated by chromic suture spacers) were preloaded into 18 gauge needles.
Source: Courtesy of John Blasko.
The procedure was performed under spinal anesthesia, with the patient in the lithotomy position. The ultrasound probe was positioned to recapitulate the volume study images. After stabilizing the gland with two empty needles, the base of the prostate was viewed on axial imaging, and the central needles (which would implant seeds at the base) were inserted first. After the central needles’ seeds were discharged, the probe was retracted 1.0 cm, and a second cohort of needles was placed. In this manner, all needles were inserted and discharged. Pubic arch interference was overcome either by freehand needle angling, or by drilling holes through the bone (118)! Postimplant dosimetry was performed on orthogonal films taken 2 weeks after implantation.
Their first patient tolerated the procedure well, but it would be several months before they would perform a second implant; thereafter, 273 men were implanted within 4 years (119). Ragde recruited patients to ultrasound and
The Seattle group reported favorable treatment outcomes at meetings and in publications (121,122). Visits from interested urologists and radiation oncologists became common; to relieve the congestion of operating room visitors, the group instituted monthly training sessions. The equipment evolved; initially, they had to cut their own chromic spacers and have their needles sharpened after every 10 cases. Their success soon attracted industry attention, and a symbiotic relationship developed. Disposable brachytherapy needles (with echogenic tips), precut spacers, stiffened Vicryl seed strands, and palladium seeds were introduced. Industry helped introduce the procedure to physicians and the public, and lobbied for physician reimbursement codes.
The initial Seattle technique was identical to the procedure performed by Holm in Denmark; why were the outcomes different? The Seattle patients had earlier disease (with more favorable prognosis) because they had been diagnosed as a result of screening. Blasko’s modified dosing and sequencing reduced the intensity of therapy, resulting in less morbidity.
The ultrasound-guided transperineal procedure was rapidly accepted in the United States, accounting for a growing percentage of patients treated for prostate cancer. Some radiation oncologists made it the focus of their practice, and introduced innovations. Urologist Nelson Stone and radiation oncologist Richard Stock correlated implant dose (123,124) and adjuvant therapy (125,126) with disease control (127,128) and urinary (129,130), rectal (131,132), and sexual toxicity (133,134). Their publications have helped establish guidelines for dosing and normal tissue constraints. They adopted intraoperative treatment planning and used a computer to monitor dose distribution as seeds were deposited, allowing real-time implant modification. Radiation oncologist Frank Critz was one of the few brachytherapists to have enjoyed success in both the retropubic (135) and transperineal (136) eras. Critz adopted ultrasound-guided implantation after taking the Seattle Prostate Institute course (1992); at its peak, his program had implanted more than 1,000 men annually. Critz was an advocate of stringent
Afterloading, Remote Afterloading, and High Dose Rate Brachytherapy
Although delayed loading of radium into previously implanted applicators had been performed as early as the first decade of the 20th century (140,141), afterloading was not seriously pursued as a radiation safety measure until the 1950s (142,143). The implantation of inert applicators facilitates deliberate, unhurried procedures (especially important for trainees), and eliminated exposure to the brachytherapist, operating-theater personnel, recovery room nurses, and radiology technicians (as well as people in the hallways through which the implanted patients passed in transit to their hospital room). It allowed dosimetric determination of optimal source distribution prior to loading. In 1953, Ulrich Henschke, Arthur James, and William Myers (at Ohio State University) described temporary interstitial brachytherapy by afterloading Au-198 seeds into previously implanted nylon tubes (144). Henschke later introduced the use of Ir-192 seeds for this purpose (145,146).r
Afterloading nylon tubing with Ir-192 became an integral part of the “Paris System” (147). Court and Chassagne described the Gustave-Roussy low dose rate (
Nisar Syed (1949−) was a surgeon prior to training in radiation oncology at Manchester’s Christie Hospital and with Henschke at Howard University. He came to the University of Southern California in 1974, where his colleagues included gynecological oncologist Philip Di Saia and physicist David Neblett. Syed and Neblett developed site-specific acrylic templates to fix transperineal needles during treatment (151). Disappointed with the results of retropubic prostate implants (more than half of his biopsied patients were found to have persistent disease), he began using a template-guided transperineal technique to temporarily implant the prostate with Ir-192 (152). After lymph node dissection and exposure of the prostate, needles were advanced to the bladder neck under guidance of a hand in the pelvis. The templates contained concentric circles of holes; initially, each hole held a needle containing a ribbon with seven seeds of 0.4 mg Ra eq strength. After several patients developed serious complications, however, the needles were differentially loaded, with central and pararectal ribbons containing half-strength seeds (153). The implants delivered 30 Gy to the prostate over 40 hours; an additional 40 Gy was delivered by linear accelerator, beginning 10 to 14 days after the implant was removed. He treated 200 patients with this technique between 1977 and 1985; of 74 patients biopsied from 4 to 24 months after treatment, only 16% had evidence of persistent disease (153).
Although manual afterloading reduced exposure to the brachytherapist and operating theater personnel, it did not address exposure to the physician loading or unloading the implant, the staff member preparing or restoring the sources, or the nursing staff caring for the implanted patient. To eliminate all exposure to personnel, remote afterloading was introduced in 1962 at Stockholm’s Radiumhemmet (154). The single channel unit, based on the source transport system of a teleradium unit (155), remotely delivered a Cs-137 source on a flexible cable into a hollow applicator. This unit, and others that soon followed (Cervitron, Curietron), essentially reproduced standard Manchester gynecological distribution and dose rates. The GammaMed, an afterloading unit with a high activity Ir-192 source deployed through a single channel, was introduced in 1964 for stereotactic treatment of brain tumors. The same year, Henschke introduced the concept of an ingenious afterloading device that could simulate an infinite variety of source loadings by cycling a single high-activity source (Figure 1.20) (156). He suggested treating patients in minutes (rather than days), declaring, “On the basis of our limited experience with such short treatment times in the last three years, we feel that they may be used with impunity if the total dose is divided into more fractions” (157).
Source: From Ref. (156). Henschke UK, Hilaris BS, Mahan GD. Remote afterloading for intracavitary radiation therapy. Prog Clin Cancer. 1965;10:127–136.
Few brachytherapists (or radiobiologists) shared Henschke’s confidence that fractionated high dose rate (
Originally,
Timothy Mate already had experience with
Source: Courtesy of Timothy Mate.
Ultrasound-directed
Computer Dosimetry
In the earliest days, brachytherapists relied on atlases, tables, and experience to determine source strength, distribution, and treatment time (176,177). By mid-century, two systems of source distribution were widely used: Paterson−Parker and Quimby. The Paterson–Parker system, developed at Manchester’s Holt Radium Institute, specified an inhomogeneous distribution of activity to achieve a relatively homogeneous dose distribution (178,179). The system developed by physicist Edith Quimby, at New York’s Memorial Hospital, stipulated a homogeneous distribution of sources to generate an inhomogeneous distribution of dose (180,181). In both cases, the systems were used for preplanning, to determine the strength and arrangement of sources required to deliver a specified minimum dose to the target.
Actual implants were often seriously flawed. It was difficult (even for expert brachytherapists) to reproduce the “ideal” source geometry specified by the systems, and the achieved “minimum” target dose typically fell well below the mark (182). The situation became more complicated with the introduction of I-125, as attenuation had to be incorporated into calculations (the inverse square law sufficed when calculating dose distribution from radium, radon, Au-198, or Ir-192) (183). Shortcomings were not recognized because postimplant dosimetric analysis was not typically performed. Manual calculation of dose at more than a few points was tedious, especially when many sources were to be identified and their dose distributions plotted and summated. A system was needed to identify a large number of sources, then calculate, summate, and spatially describe the distribution of dose over the entire volume of interest (not just the periphery). The system should be rapid enough so that decisions regarding source loading and removal could be made in a timely fashion.
In 1958, Richard Nelson and Mary Lou Meurk, physicists at New York’s Memorial Hospital, introduced a system for calculation of brachytherapy dose distribution using tabulating machines (184). Stereoshift radiographs of an implant localized the sources, which were assigned locations at the nearest point on a three-dimensional Cartesian coordinate lattice with 5 mm interspaces. The location of each source was transferred to a punch card, and the tabulating machine summed the contribution of all sources to plot a dose distribution. Only the inverse square law was considered in the calculations (which was adequate, as only high-energy sources were then in use). Output was represented as a matrix of points with 1 cm spacing; isodose lines were drawn by hand. By 1961, the system was programmed on
Radium needles and gold seeds were the sources of choice at Houston’s
Physicist Stephen Balter (1940−) revised the Memorial Hospital computer dosimetry system shortly after joining the physics staff in 1963. He wrote a program in FORTRAN II for Memorial’s
Source: Courtesy of Stephen Balter.
Source: Courtesy of Stephen Balter.
University of Washington physics graduate student Philip Heintz (1943−) collaborated with physicist Douglas Jones to generate a radiation treatment planning system from elements of the Memorial and Anderson public domain programs. Heintz rewrote the program several times while in private practice, launching it commercially as “Prowess-2000” (running on the
Physicist David Neblett introduced “
Conclusion
Brachytherapy has evolved over the century of its existence. Initially the province of surgeons, it is now performed by radiation oncologists in collaboration with medical physicists, dosimetrists, and allied specialists. Computers and stepping source applications have provided precision to the deposition of dose, increasing efficacy, and limiting toxicity. Radium and other high-energy sources have been replaced by safer radionuclides; together with remote afterloaders, they have greatly reduced or eliminated radiation exposure to the brachytherapist and other health personnel. Although the modern ultrasound-directed transperineal procedure is unsurpassed in its capacity to eradicate prostate cancer (192),
Acknowledgments
This work has benefited immeasurably from interviews with the following physicians, surgeons, physicists, engineers, and industrialists: Lowell Anderson, Claudia Andres-Zindler, Mogens Bak, Stephen Balter, Winston Barzell, Hagen Bertermann, John Blasko, Brian Butler, Eugene Carlton, Komanduri Charyulu, Frank Critz, Michael Dattoli, Jeffrey Demanes, Keith De Wyngaert, James Gottesman, Peter Grimm, Ruediger Grimm, Augusto Gutierrez, Charles Hawtrey, Bo Hansen, Henning Hansen, Philip Heintz, Claudia Henschke, Harry Herr, Basil Hilaris, Hans Henrik Holm, Eric van’t Hooft, Theodore Jackson, M. Christine Jacobs, Győrgy Kovacs, Stephan Loening, Timothy Mate, Felix Mick, Subir Nag, Dattatreyudu Nori, Colin Orton, Haakon Ragde, Michael Saylor, Peter Scardino, Pramod Sogani, Jean St. Germain, Richard Stock, Nelson Stone, Marilyn Stovall, Ivan Strøyer, Herman Suit, A. Nisar Syed, John Sylvester, Kent Wallner, and Michael Wesson.
The author also wishes to acknowledge the invaluable contributions of Martha Meacham,
Notes
a William Crookes had invented the cathode-ray tube in the 1870s, two decades before Röntgen’s discovery.
b Tuberculosis was the most dreaded disease of the 19th century; Finsen was awarded the 1903 Nobel Prize in Medicine for discovering a new mode of treatment for it.
c The price of radium peaked at $180,000 per gram in 1912.
d The term “brachyradium” (predecessor of “brachytherapy”) was proposed by Gösta Forsell in 1931 (12).
e The word dollar originates from the coins that were minted there, Joachimsthalers, or thalers.
f Thorium mined in Brazil was used in the production of Weisbach mantles, the glowing filament of gaslights and lanterns. As a result, old Coleman lantern mantles are radioactive.
g The Flannery’s vanadium was in the steel in Henry Ford’s cars and the Panama Canal locks.
h The partially refined radium was transferred (in unshielded containers) on public passenger trolleys from their Canonsburg, PA, reduction mill to their Pittsburgh facility for further purification.
i Standard Chemical ceased radium mining and refining operations in the early 1920s, but the uranium-rich slag heaps at their Canonsburg facility were exploited during World War II for the Manhattan Project. The site now holds a buried vault for containment of the toxic remnants.
j Kelly used his 4 g in a teleradium unit in the Howard Kelly Hospital in Baltimore (31).
k Memorial’s radon plant was decommissioned in 1970. The last commercial radon seed factory in the United States closed in 1981.
l Henschke’s preferred radionuclide for a low-energy seed was Cs-131, and he actually performed an implant with cesium seeds in 1965. The cost of Cs-131 production was prohibitive, and the project was abandoned (63).
m In a scandal that rocked France, Langevin became Marie Curie’s lover after Pierre’s death (104). Decades later, a Curie granddaughter (Hélène Joliot) married a Langevin grandson (Michel Langevin).
n Hertz was the son of Physics Nobel laureate Gustav Hertz and grandnephew of Heinrich Hertz, after whom the unit of wave frequency was named. Carl Hertz would later invent the inkjet printer to record ultrasound images.
o Brüel and Kjær (B&K), a Danish acoustical engineering firm, acquired the Welding Institute’s interests in sonography in 1977, and maintained the productive association with Holm.
p Loening returned to his native Germany in 1992 for a sabbatical at Berlin’s Charité Hospital and was appointed their chair of urology. He participated in the hospital’s adoption of high dose rate (
q The local medical society objected to medical advertising, but Ragde had served for three wars (in the Norwegian resistance during World War II, as a forward artillery observer in the
r Some of Henschke’s ideas were less practical; he proposed activation of inert iridium seeds after implantation, by exposing the patient to the neutron flux of a nuclear reactor (150)!
s Computation of dose distribution typically required 10 hours on the hospital’s billing computer, to which Stovall had access only at night. She napped on a cot in the business office when not feeding punch cards into the computer.
References
- Glasser O., Röntgen W. C. Dr.. Springfield, IL: Charles C Thomas; 1945.
- Curie E. Madame Curie: A Biography by Eve Curie. Garden City, NY: Doubleday, Doran; 1937.
- Bie V. Remarks on Finsen’s phototherapy. Br Med J. 1899;2(2022):825–830.
- Williams FH. The Roentgen Rays in Medicine and Surgery. 1st ed. New York, NY: MacMillan; 1901: 437–438.
- Freund L. Elements of General Radio-Therapy for Practitioners. New York, NY: Rebman; 1904.
- Allen CW. Radiotherapy and Phototherapy. New York, NY: Lea Brothers; 1904.
- Belot J. Radiotherapy in Skin Disease. London, UK: Rebman; 1905.
- Rutherford E. Radio-Activity. Cambridge, UK: University Press; 1904.
- Goldberg SW, London ES. Zur frage der beziehungen zwischen Becquerel-strahlen und hautaffectionen [On the question of relations between Becquerel rays and affections of the skin]. Dermatol Zeitschr. 1903;10:457–462.
- Lubenau JO, Mould RF. The rollercoaster price of radium. Nowotwory. 2009;59:148e−154e.
- Robison RF, Mould RF. St. Joachimstal: pitchblende, uranium and radon-induced lung cancer. Nowotwory. 2006;56:275–281.
- Forssell G. La lutte social contre le cancer [The social fight against cancer]. J Radiologie. 1931;15:621–634.
- Curran TFV. Carnotite: The Principal Source of Radium. New York, NY: Curran & Hudson; 1913.
- Landa ER. Buried treasure to buried waste: the rise and fall of the radium industry. Colorado Sch Mines Quart. 1987;82:1–77.
- Robarts H. Radiotherapy of the prostate. Am X-ray J. 1902;10:1063–1067.
- Tousey S. The treatment of tuberculosis of the larynx and the prostate gland by x-ray, high frequency currents, and the Cooper-Hewett light. Med Rec. 1904;66:364–370.
- Imbert A, Imbert L. Carcinose prostato-pelvienne diffuse, à marche aiguë, guérie par la radiothérapie [Acute diffuse prostate carcinomatosis of the pelvis, cured by radiotherapy]. Bull Acad Med Paris. 1904;52:139–143.
- Aronowitz JN, Grimard L, Robison R. Precedence for prostate brachytherapy. Brachytherapy. 2011;10(3):201–207.
- Desnos. Action du radium sur la prostate hypertrophiée [The action of radium on prostatic hypertrophy]. Proc Verb Mem Assoc Franc Urol. 1909;13:646–656.
- Minet H. Applications du radium aux tumeurs vesicales, a l’hypertrophie et au cancer de la prostate, etc [Applications of radium to bladder tumors, prostatic hypertrophy and cancer, etc.]. Proc Verb Mem Assoc Franc Urol. 1909;13:629–646.
- Pasteau O, Degrais. De l’emploi du radium dans le traitement des cancers de la prostate [The employment of radium in the treatment of prostate cancer]. J Urologie Med Chirur. 1913;4: 341–366.
- Pasteau O, Degrais. The radium treatment of cancer of the prostate. Arch Roentgen Ray. 1914;18–19:396–410.
- Wickham L, Degrais. Radium Therapie. Paris: J-B Baillière; 1909.
- Paschkis R, Tittinger W. Radiumbehandlung eines Prostatosarkoms [Radium therapy of prostate sarcomas]. Wien Klin Woch. 1910;48:1715–1716.
- Paschkis R. Radiumbehandlung von blasengeschwüisten [Radium treatment of bladder tumors]. Wien Klin Woch. 1911:1562–1564.
- Young H. The early diagnosis and radical cure of carcinoma of the prostate: being a study of 40 cases and presentatiom of a radical operation which was carried out in four cases. Bull Johns Hopkins Hosp. 1905;16:315–321.
- Young HH. Malignant tumors of the bladder and prostate. Am J Surg. 1929;40:667–678.
- Young HH. Treatment of carcinoma of the prostate. In: Young HH, Davis DM, eds. Young’s Practice of Urology: Based on a Study of 12,500 Cases. Vol. 1. 1st ed. Philadelphia, PA: WB Saunders; 1926:644–671.
- Young HH. Technique of radium treatment of the prostate and seminal vesicles. Surg Gynecol Obstet. 1922;34:93–98.
- Young HH, Waters CA. Deep Roentgen ray and radium therapy in malignant disease of the genitourinary tract. Am J Surg. 1927;2:101–125.
- Aronowitz JN, Robison RF. Howard Kelly establishes gynecologic brachytherapy in the United States. Brachytherapy. 2010;9(2):178–184.
- Cade S. Radium Treatment of Cancer. New York, NY: William Wood; 1929.
- Failla G. The physics of radium. In: Clark JG, Norris CC, eds. Radium in Gynecology. Philadelphia, PA: JB Lippincott Co; 1927:63.
- Duane W. Methods of preparing and using radioactive substances in the treatment of malignant disease and of estimating suitable doses. Boston Med J. 1917;177:787–799.
- Barringer BS. The treatment by radium of carcinoma of the prostate and bladder. JAMA. 1916;67:1442–1445.
- Barringer BS. Radium in the treatment of prostatic carcinoma. Ann Surg. 1924;80(6):881–884.
- Failla G. The development of filtered radon implants. Am J Roentgenol Radium Ther. 1926;16:507–525.
- Barringer BS. Treatment of tumors of the urinary bladder and prostate gland. In: Portmann UV, ed. Clinical Therapeutic Radiology. New York, NY: Thomas Nelson & Sons; 1950:309–322.
- Bumpus HC. Carcinoma of the prostate: a clinical study of a thousand cases. Surg Gynecol Obstet. 1926;43:150–155.
- Watson EM. A study of carcinoma of the lower urinary tract. J Urologie Med Chirur. 1933;29:545–557.
- Lubenau JO. Unwanted radioactive sources in the public domain: a historical perspective. Health Phys. 1999;76(2 . Suppl):S16–S22.
- Huggins C, Stevens RE, Hodges CV. Studies on prostatic cancer: the effects of castration on advanced carcinoma of the prostate. Arch Surg. 1941;43:209–223.
- Rose RG, Osborne MP, Stevens WB. The intracavitary administration of radioactive colloidal gold. N Engl J Med. 1952;247(18):663–667.
- Hahn PF, Goodell JP. Direct infiltration of radioactive isotopes as a means of delivering ionizing radiation to discrete tissues. J Lab Clin Med. 1947;32(12):1442–1453.
- Kerr HD, Flocks RH, Elkins HB, Culp D. The treatment of moderately advanced carcinoma of the prostate with radioactive gold. Am J Roentgenol Radium Ther Nucl Med. 1953;69(6):969–977.
- Flocks RH, Culp DA, Elkins HB. Present status of radioactive gold therapy in management of prostatic cancer. J Urol. 1959;81(1):178–184.
- Flocks RH, Kerr HD, Elkins HB, Culp D. Treatment of carcinoma of the prostate by interstitial radiation with radio-active gold (Au 198): a preliminary report. J Urol. 1952;68(2):510–522.
- Sherman AI, Bonebrake M, Allen WM. The application of radioactive colloidal gold in the treatment of pelvic cancer. Am J Roentgenol Radium Ther. 1951;66(4):624–638.
- Flocks RH, Culp DA. Radiation Therapy of Early Prostate Cancer. Springfield, IL: Charles C. Thomas; 1960.
- Elkins HB, Flocks RH, Culp DA. Evaluation of the use of colloidal radioactive gold in the treatment of prostatic carcinoma. Radiology. 1958;70(3):386–389.
- Flocks RH, Kerr HD, Elkins HB, Culp DA. The treatment of carcinoma of the prostate by interstitial radiation with radioactive gold (Au198); a follow-up report. J Urol. 1954;71(5):628–633.
- Flocks RH, O’Donoghue EP, Millerman LA, Culp DA. Management of stage C prostatic carcinoma. Urol Clin North Am. 1975;2(1):163–179.
- Flocks RH. The treatment of stage C prostatic cancer with special reference to combined surgical and radiation therapy. J Urol. 1973;109(3):461–463.
- Carlton CE Jr, Hudgins PT, Guerriero WG, Scott R Jr. Radiotherapy in the management of stage C carcinoma of the prostate. J Urol. 1976;116(2):206–210.
- Hudgins PT. Irradiation of prostatic cancer combined with abdominal exploration. In: Fletcher GH, ed. Textbook of Radiotherapy, 2nd ed. Philadelphia, PA: Lea & Febiger; 1975:768–772.
- Guerriero WG, Carlton CE Jr, Hudgins PT. Combined interstitial and external radiotherapy in the definitive management of carcinoma of the prostate. Cancer. 1980;45(7 . Suppl):1922–1923.
- Butler EB, Scardino PT, Teh BS, et al. The Baylor College of Medicine experience with gold seed implantation. Semin Surg Oncol. 1997;13(6):406–418.
- Scardino PT, Frankel JM, Wheeler TM, et al. The prognostic significance of post-irradiation biopsy results in patients with prostatic cancer. J Urol. 1986;135(3):510–516.
- Holzman M, C. E. Carlton J, Scardino PT. The frequency and morbidity of local tumor recurrence after definitive radiotherapy for stage C prostate cancer. J Urol. 1991;146:1578–1582.
- James AG, Henschke UK, Myers WG. The clinical use of radioactive gold (Au198) seeds. Cancer. 1953;6(5):1034–1039.
- James AG. The role of radioactive isotopes in carcinoma of the maxillary antrum. Am J Roentgenol Radium Ther Nucl Med. 1957;77(3):415–420.
- Henschke UK. Interstitial implantation in the treatment of primary bronchogenic carcinoma. Am J Roentgenol Radium Ther Nucl Med. 1958;79(6):981–987.
- Aronowitz JN. Don Lawrence and the “k-capture” revolution. Brachytherapy. 2010;9(4):373–381.
- Hilaris BS, Henschke UK, Holt JG. Clinical experience with long half-life and low-energy encapsulated radioactive sources in cancer radiation theapy. Radiology. 1968;91(6):1163–1167.
- Hilaris BS, Whitmore WF, Grabstald H, et al. Radical radiation therapy of cancer of the prostate: a new approach using interstitial and external sources. Clin Bull Memorial Hosp. 1972;2:94–99.
- Whitmore WF Jr. The rationale and results of ablative surgery for prostatic cancer. Cancer. 1963;16:1119–1132.
- Whitmore WF Jr. Proceedings: the natural history of prostatic cancer. Cancer. 1973;32(5):1104–1112.
- Hilaris BS, Whitmore WF, Batata M, et al. Cancer of the prostate. In: Hilaris BS, ed. Handbook of Interstitial Brachytherapy. Acton, MA: Publishing Science Group; 1975:219–234.
- Whitmore WF Jr, Hilaris B, Grabstald H. Retropubic implantation to iodine 125 in the treatment of prostatic cancer. J Urol. 1972;108(6):918–920.
- Anderson LL. Spacing nomograph for interstitial implants of 125I seeds. Med Phys. 1976;3(1):48–51.
- Hilaris BS. A Manual for Brachytherapy. 2nd ed. New York, NY: Memorial Hospital; 1970:65.
- Fowler JE Jr, Barzell W, Hilaris BS, Whitmore WF Jr. Complications of 125-iodine implantation and pelvic lymphadenectomy in the treatment of prostatic cancer. J Urol. 1979;121(4):447–451.
- Batata MA, Hilaris BS, Chu FC, et al. Radiation therapy in adenocarcinoma of the prostate with pelvic lymph node involvement on lymphadenectomy. Int J Radiat Oncol Biol Phys. 1980;6(2):149–153.
- Tokita N, Kim JH, Hilaris BS. Time-dose-volume considerations in iodine-125 interstitial brachytherapy. Int J Radiat Oncol Biol Phys. 1980;6(12):1745–1749.
- Sogani PC, DeCosse JJ Jr, Montie J, et al. Carcinoma of the prostate: treatment with pelvic lymphadenectomy and iodine-125 implants. Clin Bull. 1979;9(1):24–31.
- Stone NN, Forman JD, Sogani PC, et al. Transrectal ultrasonography and I-125 implantation in patients with prostate cancer [Abstract]. J Urol. 1988;139(Suppl):313A.
- Grossman HB, Batata M, Hilaris B, Whitmore WF Jr. 125-I implantation for carcinoma of prostate. Further follow-up of first 100 cases. Urology. 1982;20(6):591–598.
- Whitmore WF Jr, Hilaris B, Batata M, et al. Interstitial radiation: short-term palliation or curative therapy? Urology. 1985;25(2 . Suppl):24–29.
- Kuban DA, el-Mahdi AM, Schellhammer PF. I-125 interstitial implantation for prostate cancer. What have we learned 10 years later? Cancer. 1989;63(12):2415–2420.
- Morton JL, Barnes AC, Callendine GW Jr, Myers WG. Individualized interstitial irradiation of cancer of the uterine cervix using cobalt 60 in needles, inserted through a lucite template; a progress report. Am J Roentgenol Radium Ther. 1951;65(5):737–748.
- Green A. New techniques in radium and radon therapy. J Fac Radiol. 1951;2(3):206–223.
- Charyulu KKN. Transperineal interstitial implantation of prostate cancer: a new method. Int J Radiat Oncol Biol Phys. 1980;6:1261–1266.
- Kumar PP, Bartone FF. Transperineal percutaneous I-125 implant of prostate. Urology. 1981;17(3):238–240.
- Kumar PP, Good RR, Epstein BE, et al. Fluoroscopy guided transperineal percutaneous permanent 125-iodine implantation of prostate cancer. Radiat Med. 1985;3(3):161–167.
- Kumar PP, Good RR, Bartone FF. Iodine 125 interstitial irradiation for localized prostate cancer. J Natl Med Assoc. 1990;82(3):181–193.
- Kumar PP, Good RR. Vicryl carrier for I-125 seeds: percutaneous transperineal insertion. Radiology. 1986;159(1):276.
- Kumar PP, Good RR, Bartone FF, et al. Transperineal 125-iodine endocurietherapy of prostate cancer. Am J Clin Oncol. 1988;11(4):479–489.
- Linares LA, Hilaris BS, Nori D, et al. Transperineal implantation under computer tomographic and biplane fluoroscopic guidance. Endocuriether Hypertherm Oncol. 1987;3:141–146.
- Osian AD, Anderson LL, Linares LA, et al. Treatment planning for permanent and temporary percutaneous implants with custom made templates. Int J Radiat Oncol Biol Phys. 1989;16(1):219–223.
- Nori D, Donath D, Hilaris BS, et al. Precision transperineal brachytherapy in the treatment of early prostate cancer. Endocuriether Hypertherm Oncol. 1990;6:119–130.
- Lippmann G. Principe de la conservation de l’électricité [Principle of the conservation of electricity]. Ann Chim Phys. 1881;24:145–178.
- Firestone FA. The supersonic reflectoscope, an instrument for inspecting solid parts by means of sound waves. J Acous Soc Am. 1946;17:287–299.
- DeForest RE. Present status of use of ultrasonic energy in physical medicine. JAMA. 1952;148:646–651.
- Ballantine HT Jr, Bolt RH, Hueter TF, Ludwig GD. On the detection of intracranial pathology by ultrasound. Science. 1950;112(2914):525–528.
- Wild JJ. The use of ultrasonic pulses for the measurement of biologic tissues and the detection of tissue density changes. Surgery. 1950;27(2):183–188.
- Kikuchi Y, Uchida R, Tanaka K. Early cancer diagnosis through ultrasonics [Abstract]. J Acous Soc Am. 1956;28:779.
- Holm HH, Northeved A. A transurethral ultrasonic scanner. J Urol. 1974;111(2):238–241.
- Hastak SM, Gammelgaard J, Holm HH. Transrectal ultrasonic volume determination of the prostate—a preoperative and postoperative study. J Urol. 1982;127(6):1115–1118.
- Holm HH, Gammelgaard J. Ultrasonically guided precise needle placement in the prostate and the seminal vesicles. J Urol. 1981;125(3):385–387.
- Holm HH, Strøyer I, Hansen H, Stadil F. Ultrasonically guided percutaneous interstitial implantation of iodine 125 seeds in cancer therapy. Br J Radiol. 1981;54(644):665–670.
- Joyce F, Burcharth F, Holm HH, Strøyer I. Ultrasonically guided percutaneous implantation of iodine-125 seeds in pancreatic carcinoma. Int J Radiat Oncol Biol Phys. 1990;19(4):1049–1052.
- Holm HH, Juul N, Pedersen JF, et al. Transperineal 125-iodine seed implantation in prostatic cancer guided by transrectal ultrasonography. J Urol. 1983;130(2):283–286.
- Henschke UK, Cevc P. Dimension averaging a simple method for dosimetry of interstitial implants. Radiobiol Radiother (Berl). 1968;9(3):287–298.
- Anon. France divided on Curie case; government and scientists are anxious to put a stop to the scandal. NY Times. November 28, 1911:1–2.
- Holm HH. The history of interstitial brachytherapy of prostatic cancer. Semin Surg Oncol. 1997;13(6):431–437.
- Iversen P, Bak M, Juul N, et al. Ultrasonically guided iodine-125 seed implantation with external radiation in management of localized prostatic carcinoma. Urology. 1989;34(4):181–186.
- Iversen P, Rasmussen F, Holm HH. Long-term results of ultrasonically guided implantation of 125-I seeds combined with external irradiation in localized prostatic cancer. Scand J Urol Nephrol Suppl. 1991;138:109–115.
- Hammer J, Riccabona M. Transperineal technique of iodine-125 implantation. In: Bruggmoser G, Sommerkamp H, Mould RF, eds. Brachytherapy of Prostatic Cancer. Aylesbury, UK: BPCC Hazell Books; 1990:101–116.
- Frankenschmidt A, Bruggmoser G, Hempel M. Interstitial radiotherapy with iodine-125 in prostatic cancer. In: Bruggmoser G, Sommerkamp H, Mould RF, eds. Brachytherapy of Prostatic Cancer. Aylesbury, UK: BPCC Hazell Books; 1991:125–134.
- Hellawell GO, Ho K, Halliwell M, et al. Long-term outcomes and morbidity after I125 brachytherapy for localised prostate cancer: An early UK series. Clin Oncol (R Coll Radiol). 2005;17(1):68–69.
- Vijverberg PL, Kurth KH, Blank LE, et al. Treatment of localized prostatic carcinoma using the transrectal ultrasound guided transperineal implantation technique. Eur Urol. 1992;21(1):35–41.
- Hochstetler JA, Kreder KJ, Brown CK, Loening SA. Survival of patients with localized prostate cancer treated with percutaneous transperineal placement of radioactive gold seeds: stages A2, B, and C. Prostate. 1995;26(6):316–324.
- Loening SA, Rosenberg SJ. Percutaneous placement of radioactive gold seeds in localized prostatic carcinoma. Urology. 1987;29(3):250–252.
- Crusinberry RA, Kramolowsky EV, Loening SA. Percutaneous transperineal placement of gold 198 seeds for treatment of carcinoma of the prostate. Prostate. 1987;11(1):59–67.
- Loening SA, Kwon ED. Percutaneous placement of radioactive gold seeds for treatment of localized prostatic carcinoma. J Endourol. 1989;3:201–208.
- Torp-Pedersen S, Holm HH, Littrup PJ. Transperineal I-125 seed implantation in prostate cancer guided by transrectal ultrasound. In: Lee F, McLeary RD, eds. The Use of Transrectal Ultrasound in the Diagnosis and Management of Prostate Cancer. New York, NY: Alan R Liss; 1987:151.
- Blasko JC, Ragde H, Schumacher D. Transperineal percutaneous iodine-125 implantation for prostatic carcinoma using transrectal ultrasound and template guidance. Endocuriether Hypertherm Oncol. 1987;3:131–139.
- Ragde H, Blasko JC, Schumacher D, et al. Treatment of localized prostate carcinoma with iodine-125 seeds percutaneously placed under transrectal ultrasound and template guidance. Endosonographique. 1987:3–14.
- Blasko JC, Ragde H, Grimm PD. Transperineal ultrasound-guided implantation of the prostate: morbidity and complications. Scand J Urol Nephrol Suppl. 1991;137:113–118.
- Mate TP, Blasko JC, Marshall S, et al. CT assisted permanent prostate implant dosimetry. Twelfth annual mid-winter meeting of the American Endocurietherapy Society. 1989.
- Blasko JC, Wallner K, Grimm PD, Ragde H. Prostate specific antigen based disease control following ultrasound guided iodine-125 implantation for stage T1/T2 prostatic carcinoma. J Urol. 1995;154(3):1096–1099.
- Prestidge BR, Hoak DC, Grimm PD, et al. Posttreatment biopsy results following interstitial brachytherapy in early-stage prostate cancer. Int J Radiat Oncol Biol Phys. 1997;37(1):31–39.
- Stock RG, Stone NN, Tabert A, et al. A dose-response study for I-125 prostate implants. Int J Radiat Oncol Biol Phys. 1998;41(1):101–108.
- Stone NN, Stock RG, Cesaretti JA, Unger P. Local control following permanent prostate brachytherapy: effect of high biologically effective dose on biopsy results and oncologic outcomes. Int J Radiat Oncol Biol Phys. 2010;76(2):355–360.
- Stock RG, Stone NN, Kao J, et al. The effect of disease and treatment-related factors on biopsy results after prostate brachytherapy: implications for treatment optimization. Cancer. 2000;89(8):1829–1834.
- Lee LN, Stock RG, Stone NN. Role of hormonal therapy in the management of intermediate- to high-risk prostate cancer treated with permanent radioactive seed implantation. Int J Radiat Oncol Biol Phys. 2002;52(2):444–452.
- Stone NN, Stock RG, White I, Unger P. Patterns of local failure following prostate brachytherapy. J Urol. 2007;177(5):1759–63; discussion 1763.
- Stock RG, Buckstein M, Liu JT, Stone NN. The relative importance of hormonal therapy and biological effective dose in optimizing prostate brachytherapy treatment outcomes. BJU Int. 2013;112(2):E44–E50.
- Stone NN, Marshall DT, Stone JJ, et al. Does neoadjuvant hormonal therapy improve urinary function when given to men with large prostates undergoing prostate brachytherapy? J Urol. 2010;183(2):634–639.
- Stone NN, Gerber NK, Blacksburg S, et al. Factors influencing urinary symptoms 10 years after permanent prostate seed implantation. J Urol. 2012;187(1):117–123.
- Snyder KM, Stock RG, Hong SM, et al. Defining the risk of developing grade 2 proctitis following 125-I prostate brachytherapy using a rectal dose-volume histogram analysis. Int J Radiat Oncol Biol Phys. 2001;50(2):335–341.
- Price JG, Stone NN, Stock RG. Predictive factors and management of rectal bleeding side effects following prostate cancer brachytherapy. Int J Radiat Oncol Biol Phys. 2013;86(5):842–847.
- Stock RG, Stone NN, Iannuzzi C. Sexual potency following interactive ultrasound-guided brachytherapy for prostate cancer. Int J Radiat Oncol Biol Phys. 1996;35(2):267–272.
- Snyder KM, Stock RG, Buckstein M, Stone NN. Long-term potency preservation following brachytherapy for prostate cancer. BJU Int. 2012;110(2):221–225.
- Critz FA, Tarlton RS, Holladay DA. Prostate specific antigen-monitored combination radiotherapy for patients with prostate cancer. I-125 implant followed by external-beam radiation. Cancer. 1995;75(9):2383–2391.
- Critz FA, Williams WH, Levinson AK, et al. Simultaneous irradiation for prostate cancer: intermediate results with modern techniques. J Urol. 2000;164(3 . Pt 1):738–741; discussion 741.
- Critz FA, Williams WH, Holladay CT, et al. Post-treatment PSA < or = 0.2 ng/mL defines disease freedom after radiotherapy for prostate cancer using modern techniques. Urology. 1999;54(6):968–971.
- Critz FA, Levinson K. 10-year disease-free survival rates after simultaneous irradiation for prostate cancer with a focus on calculation methodology. J Urol. 2004;172(6 . Pt 1):2232–2238.
- Critz FA, Benton JB, Shrake P, Merlin ML. 25-Year disease-free survival rate after irradiation for prostate cancer calculated with the prostate specific antigen definition of recurrence used for radical prostatectomy. J Urol. 2013;189(3):878–883.
- Strebel H. Vorschläge zur radiumtherapie [proposals for radium therapy]. Duetsche Med-Zeit. 1903;24:1145–1146.
- Abbe R. Radium’s contribution to surgery. JAMA. 1910;55:97–100.
- Fishman R, Citrin LI. A new radium implant technique to reduce operating room exposure and increase accuracy of placement. Am J Roentgenol Radium Ther Nucl Med. 1956;75(3):495–496.
- Henschke UK. “Afterloading” applicator for radiation therapy of carcinoma of the uterus. Radiology. 1960;74:834.
- Henschke UK, James AG, Myers WG. Radiogold seeds for cancer therapy. Nucleonics. 1953;11:46–48.
- Henschke UK. A technique for permanent implantation of radioiotopes. Radiology. 1957;68:256.
- Sklaroff DM. Treatment of malignant tumors by the interstitial implantation of radioactive iridium (Ir-192). J Albert Einstein Med Cent (Phila). 1956;4(4):147–152.
- Pierquin B. Précis de curiethérapie: Endocuriethérapie, plésiothérapie. [A concise summary of curietherapy: Endocurietherapy and plesiotherapy.]. Paris: Masson; 1964.
- Court B, Chassagne D. Interstitial radiation therapy of cancer of the prostate using iridium 192 wires. Cancer Treat Rep. 1977;61(2):329–330.
- Miller LS. After-loading transperineal iridium-192 wire implantation of the prostate. Radiology. 1979;131(2):527–528.
- Henschke UK, Hilaris BS, Mahan GD. Afterloading in interstitial and intracavitary radiation therapy. Am J Roentgenol Radium Ther Nucl Med. 1963;90:386–395.
- Syed AM, Puthawala A, Neblett D, et al. Primary treatment of carcinoma of the lower rectum and anal canal by a combination of external irradiation and interstitial implant. Radiology. 1978;128(1):199–203.
- Syed AM, Puthawala A, Tansey LA, et al. Management of prostate carcinoma. Combination of pelvic lymphadenectomy, temporary Ir-192 implantation, and external irradiation. Radiology. 1983;149(3):829–833.
- Syed AM, Puthawala A, Austin P, et al. Temporary iridium-192 implant in the management of carcinoma of the prostate. Cancer. 1992;69(10):2515–2524.
- Walstam R. Remotely-controlled afterloading radiotherapy apparatus. (A preliminary report). Phys Med Biol. 1962;7:225–228.
- Lindell B, Walstam R. A new telegamma apparatus. Acta radiol. 1956;45(3):236–248.
- Henschke UK, Hilaris BS, Mahan GD. Remote afterloading for intracavitary radiation therapy. Prog Clin Cancer. 1965;10:127–136.
- Henschke UK, Hilaris BS, Mahan GD. Remote afterloading with intracavitary applicators. Radiology. 1964;83:44–45.
- O’Connell D, Howard N, Joslin CA, et al. A new remotely controlled unit for the treatment of uterine carcinoma. Lancet. 1965;2(7412):570–571.
- Joslin CA, O’Connell D, Howard N. The treatment of uterine carcinoma using the Cathetron. Part III. Clinical considerations and preliminary reports on treatment results. Br J Radiol. 1967;40(480):895–904.
- Liversage WE. A general formula for equating protracted and acute regimes of radiation. Br J Radiol. 1969;42(498):432–440.
- O’Connell D, Joslin CA, Howard N, et al. The treatment of uterine carcinoma using the Cathetron. Part I. Technique. Br J Radiol. 1967;40(480):882–887.
- O’Connell D. A technique of afterloading: high dose-rates. Proc Roy Soc Med. 1973;66:12–13.
- Bertermann H. The European experience: use of transrectal ultrasound in the diagnosis and management of prostate cancer. Prog Clin Biol Res. 1987;237:177–194.
- Bertermann H, Brix F. Ultrasonically guided interstitial high dose brachytherapy with iridium-192: technique and preliminary results in locally confined prostate cancer. In: Martinez AA, Orton CG, Mould RF, eds. Brachytherapy HDR and LDR. Columbia, MD: Nucletron; 1990:281–303.
- Galalae RM, Zakikhany NH, Geiger F, et al. The 15-year outcomes of high-dose-rate brachytherapy for radical dose escalation in patients with prostate cancer—a benchmark for high-tech external beam radiotherapy alone? Brachytherapy. 2014;13(2):117–122.
- Galalae RM, Kovács G, Schultze J, et al. Long-term outcome after elective irradiation of the pelvic lymphatics and local dose escalation using high-dose-rate brachytherapy for locally advanced prostate cancer. Int J Radiat Oncol Biol Phys. 2002;52(1):81–90.
- Mate TP, Kwiatkowski TM, Hatton JW. Remote HDR afterloading brachytherapy: a preliminary report. Activity Selectron Brachyther J. 1990;4:65–67.
- Mate TP, Gottesman JE, Hatton J, et al. High dose-rate afterloading Iridium-192 prostate brachytherapy: feasibility report. Int J Radiat Oncol Biol Phys. 1998;41(3):525–533.
- McLean B. Taking on prostate cancer. Fortune. May 13, 1996. http://archive.fortune.com/magazines/fortune/fortune_archive/1996/05/13/212394/index.htm
- Edmundson GK, Rizzo NR, Teahan M, et al. Concurrent treatment planning for outpatient high dose rate prostate template implants. Int J Radiat Oncol Biol Phys. 1993;27(5):1215–1223.
- Martinez AA, Gustafson G, Gonzalez J, et al. Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer. Int J Radiat Oncol Biol Phys. 2002;53(2):316–327.
- Martinez AA, Gonzalez J, Ye H, et al. Dose escalation improves cancer-related events at 10 years for intermediate- and high-risk prostate cancer patients treated with hypofractionated high-dose-rate boost and external beam radiotherapy. Int J Radiat Oncol Biol Phys. 2011;79(2):363–370.
- Brenner DJ, Martinez AA, Edmundson GK, et al. Direct evidence that prostate tumors show high sensitivity to fractionation (low alpha/beta ratio), similar to late-responding normal tissue. Int J Radiat Oncol Biol Phys. 2002;52(1):6–13.
- Ghilezan M, Martinez A, Gustason G, et al. High-dose-rate brachytherapy as monotherapy delivered in two fractions within one day for favorable/intermediate-risk prostate cancer: preliminary toxicity data. Int J Radiat Oncol Biol Phys. 2012;83(3):927–932.
- Demanes DJ, Martinez AA, Ghilezan M, et al. High-dose-rate monotherapy: safe and effective brachytherapy for patients with localized prostate cancer. Int J Radiat Oncol Biol Phys. 2011;81(5):1286–1292.
- Janeway HH. The use of buried emanation in the treatment of malignant tumors. Am J Roentgenol. 1920;7:325–327.
- Quick D, Martin HE. Compendium for the Housestaff; Memorial Hospital, New York City. New York, NY: Paul B. Hoeber; 1927:63–70.
- Paterson R, Parker HM. A dosage system for gamma-ray therapy. Brit J Radiol. 1934;7:592–612.
- Paterson R, Parker HM. A dosage system for interstitial radium therapy. Brit J Radiol. 1938;11:252–266.
- Quimby EH. Physical factors in interstitial radium therapy. Am J Roentgenol. 1935;33:306–316.
- Quimby EH. Dosage table for linear radium sources. Radiology. 1944;43:572–577.
- Balter S, Freed BR, Ragazzoni GD, et al. An extension of the Memorial system for implant dosimetry. Radiology. 1966;87(3):475–482.
- Anderson LL, Aubrey RF. Computerized dosimetry for I-125 prostate implants. In: Hilaris BS, Batata MA, eds. Brachytherapy Oncology-1983. New York, NY: Memorial Sloan-Kettering; 1983:57–63.
- Nelson RF, Meurk ML. The use of automatic computing machines for implant dosimetry. Radiology. 1958;70(1):90.
- Laughlin JS, Siler WM, Holodny EI, et al. A dose description system for interstitial radiation therapy. Am J Roentgenol Radium Ther Nuclear Med. 1963;89:470–490.
- Shalek RJ, Stovall MA. The calculation of isodose distributions in interstitial implantations by a computer. Radiology. 1961;76:119–120.
- Fletcher GH, Stovall M. A study of the explicit distribution of radiation in interstitial implantations. II. Correlation with clinical results in squamous-cell carcinomas of the anterior two-thirds of tongue and floor of mouth. Radiology. 1962;78:766–782.
- Shalek RJ, Stovall M. The computation of dosage in interstitial and intracavitary radiation therapy. J Chronic Dis. 1966;19(4):519–522.
- Holt G, Hilaris B, Balter S, et al. Experience with computerized implant dosimetry. Am J Roentgenol Radium Ther Nucl Med. 1968;102(3):688–693.
- Holt JG, Balter S, Baker A, et al. Experience with a dose distribution computation service. Ann N Y Acad Sci. 1969;161(1):344–347.
- Randall G, Balter S, Holt JG, Laughlin JS. The Memorial implant dosimetry automated system. Comput Programs Biomed. 1972;2(3):137–152.
- Grimm P, Billiet I, Bostwick D, et al. Comparative analysis of prostate-specific antigen free survival outcomes for patients with low, intermediate and high risk prostate cancer treatment by radical therapy. Results from the Prostate Cancer Results Study Group. BJU Int. 2012;109(Suppl 1):22–29.