- Email: [email protected]
History of Japan's radioactive sources for brachytherapy
Abstracts / Brachytherapy 7 (2008) 91e194 Conclusions: This is a clinically promising method to preserve quality of life in patients with few desirable therapeutic options. Monte Carlo dosimetry should be developed around this approach in order to better understand how to optimize patient safety and oncologic efficacy because in the setting of re-irradiation near the spinal cord, low-dose-rate brachytherapy with low energy sources affords the widest possible safety margin of available radiation based options. We have initiated a phase I trial for such patients in order to assess its feasibility in a wider array of patient presentations.
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The systemic decrease of SUVmax may be a reaction of the metabolism after implantation and/or generally anesthesia. In no case was it possible to use the FDG PET/CT signal for brachytherapy treatment planning. Conclusions: Currently FDG PET/CT is not useful in brachytherapy treatment planning of head and neck tumors, because there is no correlation between clinical examination, MRI and FDG PET/ CT isocontour. In evaluating the usefulness of the FDG PET signal the investigation should always be performed before therapy because of signal changes after implantation.
PO80 Interstitial high-dose-rate brachytherapy combined or not with external beam radiotherapy for recurrent cervical cancer. Can it compensate marginal surgical resections? Antonio C.A. Pellizzon, M.D., Ph.D., J. Salvajoli, M.D., Pers Novaes, Maia Maria, R. Fogaroli. Radiation Oncology, Hospital Acacamargo, Sao Paulo, SP, Brazil. Purpose: Salvage therapy in head and neck cancer (HNC) is controversial issue and the literature is scarce regarding the use of interstitial high-doserate brachytherapy (I-HDR), although surgery is mandatory when feasible. We evaluated the long-term results of a treatment policy combining salvage surgery and interstitial high-dose-rate brachytherapy (I-HDR) for cervical recurrences of HNC. Methods and Materials: Charts of patients with recurrent cervical cancer with primary origin in the head and neck, treated with surgery combined to I-HDR between 1994 and 2004 were reviewed. At the time of operation all patients had an interstitial implant of catheters for brachytherapy. Results: Twenty-one patients with a median age 53.5 years were evaluable. The crude local control rate for all patients was 52.4%. The 8- and 10-year overall (OS) and local relapse-free survival (LRFS) rates were, 42.9%, 42.5%, 28.6% and 27%, respectively. The only predictive factor associated to LFRS and OS was negative margin status (p 5 0.0007 and p 5 0.0002). Conclusions: We conclude that complete surgery is mandatory for long term control. The doses given by brachytherapy are not high enough to compensate for microscopic residual disease after surgery. Studies and strategies involving the use of concurrent chemotherapy and new drugs are still necessary.
PO82 Present status of brachytherapy in Japan: A survey result Tetsuo Nishimura, M.D.1 Yasuo Yoshioka, M.D.2 Masahiro Kenjo, M.D.3 Takayuki Nose, M.D.4 Takashi Yamashita, M.D.4 Masato Hareyama, M.D.5 1 Radiation Oncology, Shizuoka Cancer Center, Nagaizumi, Shizuoka, Japan; 2Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Radiology, Hiroshima University Graduate School of Medicine, Hiroshima, Hiroshima, Japan; 4Radiation Oncology, Cancer Institute Ariake Hospital, Tokyo, Tokyo, Japan; 5 Radiology, Sapporo Medical University, Sapporo, Hokkaido, Japan. Purpose: To show survey results on brachytherapy (BT) in Japan conducted by the Japanese Group of Brachytherapy/Japanese Society for Therapeutic Radiology and Oncology (JGB/JASTRO). Methods and Materials: Questionnaires on BT practice were sent to 255 facilities in April 2007. Results: All facilities completed the questionnaire. There were 214 BT facilities in April 2007. There were 206 remote afterloading units HDR60Co (Ralstron):49, HDR60Co installed; HDR192Ir:131, (Multisource):12, MDR137Cs:4. The total number of BT patients in 2006 was 6529 (HDR: 3882, LDR: 2638, MDR: 9) including 3012 gynecology (HDR: 2889, LDR: 114, MDR: 9), 2669 prostate (HDR: 564, LDR 2105), 348 head and neck (HDR: 83, LDR: 265), 500 others (HDR: 346, LDR: 154). The number of patients treated with permanent seed implantation for prostate cancers has rapidly increased. Conclusions: These results advocate the continuation of the survey to demonstrate the developments in the field of brachytherapy.
PO81
PO83
FDG PET/CT in head and neck brachytherapy Annedore R. Strnad, M.D.1 Torsten Fritscher, M.D.2 Alexander Cavallaro, M.D.3 Matthias Geiger, M.D.1 Rolf Sauer, M.D.1 Vratislav Strnad, M.D.1 1 Radiation Oncology, University ErlangeneNuremberg, Erlangen, Germany; 2Nuclear Medicine, University ErlangeneNuremberg, Erlangen, Germany; 3University ErlangeneNuremberg, Erlangen, Germany.
History of Japan’s radioactive sources for brachytherapy Takashi Yamashita, M.D., Takayuki Nose, M.D., Yutaka Takahashi, Ph.D. Radiation Oncology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan.
Purpose: We studied the value of FDG PET/CT investigation for treatment planning in patients with head and neck cancer who were treated with interstitial brachytherapy alone. Methods and Materials: From 3/2007 e 10/2007 8 patients with tumors of the tongue or tumors of the floor of the mouth were investigated by FDG PET/CT before and one day after implantation of plastic tubes for interstitial brachytherapy. At the same time all patients received an MRI of the head. Results: 6/8 patients had tumors that showed an active glucose storing signal in FDG PET/CT before and one day after implantation of plastic tubes. In 50% of patients the active glucose storing signal did not correspond to clinical tumor extension. Comparison of MRI and FDG PET/CT showed correspondence in 5/8 cases, only. The SUVmax in the active glucose storing tumor regions was between 7.8 and 23.8 before implantation and between 5.6 and 15 one day after implantation. Comparing all FGD PET/CT investigations before and one day after implantation there was in 6 cases a systemic decrease in SUVmax in reference organs and a decrease in SUVmax in the tumor region. In 2 cases the systemic and local SUVmax stayed nearly the same.
Purpose: To review the history of radioisotopes for brachytherapy in Japan. Methods and Materials: All data were collected from the Japan Radioisotope Association (JRIA) and the Japanese Foundation of Cancer Research (JFCR). Results: Brachytherapy in Japan began at the Cancer Institute Hospital in 1939 at which time 5-gram radium sources were imported from Belgium. Soon afterwards other institutions and hospitals introduced radium sources for treatment of head and neck and skin cancers. Such sources were used for not only brachytherapy but also teletherapy. After World War II, the government set up JRIA to regulate isotopes for protecting medical workers and the general public from radiation hazard. Although a private institution, JRIA controlled all radioactive materials throughout Japan, even those for industrial purposes. In 1947, JFCR started to produce radon seeds for medical use. This source was used mainly for head and neck cancers between 1947 and 1975; JRIA also distributed this product to other Japanese hospitals. Low (LDR) and high (HDR) dose rates of iridium sources, distributed via JRIA, have been made at the Japanese Atomic Power Station since 1982. About 210,000 radon seeds were used during those three decades. The use of HDR Ir-192 sources has rapidly increased since 1986 in which year JRIA recommended the suspension of radium and LDR cobalt as treatment sources. Iodine-125 prostate permanent implant brachytherapy was begun in 2003 after prolonged
166
Abstracts / Brachytherapy 7 (2008) 91e194
negotiations with the government. About 6,880 prostate cancer patients in 79 hospitals have been treated by permanent seed treatment as of 2007. About 400,000 I-125 seeds were used in the most recent 5 years. Conclusions: The use of radioisotopes in brachytherapy in Japan has significantly changed in recent years. In particular, the number of sources in clinical use has rapidly increased in the past 70 years. Such data indicate that radiation safety and protection systems have become increasingly more important factors in cancer treatment in Japan. PO84 Role of high-dose-rate brachytherapy as palliative treatment for obstructive malignant jaundice G.C. Mattiucci1 E. Ippolito1 D. Smaniotto1 B. De Bari1 S. Luzi1 G. Mantini1 M. Mutignani2 V. Valentini1 G. Costamagna2 N. Cellini1 1 Radiation Oncology, Catholic University, Rome, Italy; 2Surgical Sciences, Catholic University, Rome, Italy. Purpose: Extrahepatic bile duct cancer is an uncommon disease often diagnosed at an advanced stage. The great majority of patients are not suitable for curative surgery. In this setting, the therapeutic goal is often palliative. Given a short life expectancy, the most feasible radiotherapy treatment should be the hypofractionated short course schedule, which can be performed either by external beam radiotherapy or high-dose-rate intraluminal brachytherapy (ILBT). The aim of this study is to evaluate the effectiveness of intraluminal brachytherapy in the treatment of obstructive malignant jaundice in terms of outcome and toxicity. Methods and Materials: Patients affected by extrahepatic biliary tract carcinoma, proven by biopsy, unsuitable to undergo surgery or radio chemotherapy because of age O80 years or comorbidities (value O8 according to score of Charlson 1994), were treated with ILBT alone delivered by transhepatic or endoscopic retrograde route. ILBT was performed using a high-activity 192Ir source (microSelectron remote afterloading system Nucletron). The radiation dose of the HDR-192Ir ILBT was prescribed at 10 mm from the center of the source with a single daily dose of 500 cGy to a total dose of 20e25 Gy given in four-five days. We evaluated the compliance of patients, the grade of toxicity according to RTOG scale and the median time of stent patency for each patient. Results: From May 2004 to June 2007 12 patients (7 females, 5 males) affected by extrahepatic cholangiocarcinoma (n 5 11) and ampulloma (n 5 1) were treated .The stage of disease at diagnosis was IA (n 5 1), IB (n 5 7), II A (n 5 2), III (n 5 2). Among the patients affected by cholangiocarcinoma, tumor location was as follows: hepatic duct bifurcation (n 5 2), common hepatic duct (n 5 2), common bile duct (n 5 6), hepatic duct bifurcation plus common bile duct (n 5 1). All patients before treatment had jaundice. ECOG performance status was 3 (n 5 4), 2 (n 5 3), 1 (n 5 4) and 0 (1). Eleven patients completed the treatment. In one patient the last application could not be performed due to the poor compliance of the patient. The median time of stent patency was 5 months (range: 3e20). Cholangitis occurred in 2 patients. One patient experienced hemobilia. No gastrointestinal bleeding was recorded. Median overall survival was 11 months (range 4e26). Conclusions: Hypofractionated short course schedule performed by transduodenal HDR-192Ir brachytherapy is feasible and represents a safe palliative therapy in treating malignant obstructive jaundice. Dose escalation prospective studies are expected also to investigate the potentiality of extending survival in these patients.
PO85 Intraoperative brachytherapy in the management of high-risk neck node metastasis: Two case reports from Rajiv Gandhi Cancer Institute Preeti Bagga, DNB1 Anil Kumar Anand, M.D.1 Pritam Singh Negi, FUICC2 Ram Kishan Munjal, M.Sc.2 Avtar Raina, M.D.1 Amal Roy Chaudhoory, M.D.1 Kapil Kumar, FICS.3 1Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India; 2Medical Physics, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India;
3
Surgical Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India. Purpose: To explore the feasibility of intraoperative brachytherapy boost in patients with neck node metastasis having poor prognostic features in combination with surgery and postoperative external beam radiotherapy. Methods and Materials: Two cases of neck node metastasis associated with extra capsular extension underwent radical neck dissection and intra operative brachytherapy to the tumor bed followed by external beam radiotherapy. A Freiberg applicator with six catheters was sutured to the pre-vertebral fascia during modified radical neck dissection. A 10 Gy dose was delivered intraoperatively. Subsequently the neck was treated with external radiation to a dose of 45 Gy in 24-fr. Results: At a median followup 21 months both patients were locally disease-free. The procedure was well tolerated and morbidity was minimal. One patient developed sensation at the site of surgery and both patients complained of grade II xerostomia (CTC version 3). Conclusions: For locally advanced and recurrent neoplasms, where local control is a major factor in patient outcome, IORT does provide a therapeutic edge when integrated with surgery and EBRT.
PHYSICS POSTERS SundayeTuesday May 4, 2008 e May 6, 2008 7:00 AMe6:00 PM PO86 Evaluation of 192Ir high-dose-rate rectal brachytherapy treatment plans using a fast Monte Carlo photon transport code Emily Poon, M.Sc.1 Jeffrey F. Williamson, Ph.D.2 Frank Verhaegen, Ph.D.1 1 Medical Physics, McGill University, Montreal, QC, Canada; 2Medical Physics, Radiation Oncology, Virginia Commonwealth University, Richmond, VA. Purpose: To retrospectively evaluate the treatment plans of a rectal cancer patient cohort who received 192Ir high-dose-rate (HDR) brachytherapy with a metal-shielded intracavitary mould applicator. Using fast Monte Carlo (MC) techniques, dose perturbations due to applicator and anatomical heterogeneities and their effects on the target dose coverage were examined. Methods and Materials: Forty rectal treatment plans generated from a TG43-based brachytherapy planning system (BPS) were re-calculated using PTRAN_CT, which is an extension of the well-benchmarked PTRAN photon transport code designed for accelerated patient dose calculations. An image-based treatment planning and analysis tool was developed with capabilities to efficiently extract patient data from the BPS and to enable MC calculations. In the MC simulations, scatter and attenuation in the applicator and the shielding were explicitly modeled. Patient materials and densities were assigned to 2x2x2 mm3 voxels according to CT data, with adjustments made to correctly identify bony structures, metal clips, and contrast medium. Additionally, a kernel superposition algorithm that makes use of PTRAN pre-generated dose kernels was implemented. This superposition approach accounts for applicator heterogeneities and has the same computational efficiency as the TG43 2D algorithm. The kernels have been validated using Gafchromic EBT film measurements in water. Results: Metal shielding provides significant tissue sparing for patients with non-circumferential tumors, and causes negligible dose perturbations on the unshielded side. Depending on the source loading configuration, 40% to 85% dose reduction to normal tissues can be achieved. However, the shielding also led to cold spots in 12 of the 40 patient plans. The V100 calculated using PTRAN_CT, kernel superposition, and TG43 2D algorithms were 94 5%, 94 5%, and 97 3%, respectively. Anatomical heterogeneities did not affect the target dose, while differences of 3% to 15% were found in bony structures and in regions behind air cavities. PTRAN_CT can achieve 2% uncertainty in a 29 cm3 target in 2.5 min, 4.1 min, and 6.6 min on a 2.8 GHz processor when using 40 40 40, 60 60 60, and 80 80 80 voxels, respectively. Conclusions: MC-based treatment planning is recommended for HDR rectal brachytherapy to achieve conformal dose distributions with sufficient target coverage, especially when metal shielding is used. Research sponsored by Nucletron BV.
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The systemic decrease of SUVmax may be a reaction of the metabolism after implantation and/or generally anesthesia. In no case was it possible to use the FDG PET/CT signal for brachytherapy treatment planning. Conclusions: Currently FDG PET/CT is not useful in brachytherapy treatment planning of head and neck tumors, because there is no correlation between clinical examination, MRI and FDG PET/ CT isocontour. In evaluating the usefulness of the FDG PET signal the investigation should always be performed before therapy because of signal changes after implantation.
PO80 Interstitial high-dose-rate brachytherapy combined or not with external beam radiotherapy for recurrent cervical cancer. Can it compensate marginal surgical resections? Antonio C.A. Pellizzon, M.D., Ph.D., J. Salvajoli, M.D., Pers Novaes, Maia Maria, R. Fogaroli. Radiation Oncology, Hospital Acacamargo, Sao Paulo, SP, Brazil. Purpose: Salvage therapy in head and neck cancer (HNC) is controversial issue and the literature is scarce regarding the use of interstitial high-doserate brachytherapy (I-HDR), although surgery is mandatory when feasible. We evaluated the long-term results of a treatment policy combining salvage surgery and interstitial high-dose-rate brachytherapy (I-HDR) for cervical recurrences of HNC. Methods and Materials: Charts of patients with recurrent cervical cancer with primary origin in the head and neck, treated with surgery combined to I-HDR between 1994 and 2004 were reviewed. At the time of operation all patients had an interstitial implant of catheters for brachytherapy. Results: Twenty-one patients with a median age 53.5 years were evaluable. The crude local control rate for all patients was 52.4%. The 8- and 10-year overall (OS) and local relapse-free survival (LRFS) rates were, 42.9%, 42.5%, 28.6% and 27%, respectively. The only predictive factor associated to LFRS and OS was negative margin status (p 5 0.0007 and p 5 0.0002). Conclusions: We conclude that complete surgery is mandatory for long term control. The doses given by brachytherapy are not high enough to compensate for microscopic residual disease after surgery. Studies and strategies involving the use of concurrent chemotherapy and new drugs are still necessary.
PO82 Present status of brachytherapy in Japan: A survey result Tetsuo Nishimura, M.D.1 Yasuo Yoshioka, M.D.2 Masahiro Kenjo, M.D.3 Takayuki Nose, M.D.4 Takashi Yamashita, M.D.4 Masato Hareyama, M.D.5 1 Radiation Oncology, Shizuoka Cancer Center, Nagaizumi, Shizuoka, Japan; 2Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Radiology, Hiroshima University Graduate School of Medicine, Hiroshima, Hiroshima, Japan; 4Radiation Oncology, Cancer Institute Ariake Hospital, Tokyo, Tokyo, Japan; 5 Radiology, Sapporo Medical University, Sapporo, Hokkaido, Japan. Purpose: To show survey results on brachytherapy (BT) in Japan conducted by the Japanese Group of Brachytherapy/Japanese Society for Therapeutic Radiology and Oncology (JGB/JASTRO). Methods and Materials: Questionnaires on BT practice were sent to 255 facilities in April 2007. Results: All facilities completed the questionnaire. There were 214 BT facilities in April 2007. There were 206 remote afterloading units HDR60Co (Ralstron):49, HDR60Co installed; HDR192Ir:131, (Multisource):12, MDR137Cs:4. The total number of BT patients in 2006 was 6529 (HDR: 3882, LDR: 2638, MDR: 9) including 3012 gynecology (HDR: 2889, LDR: 114, MDR: 9), 2669 prostate (HDR: 564, LDR 2105), 348 head and neck (HDR: 83, LDR: 265), 500 others (HDR: 346, LDR: 154). The number of patients treated with permanent seed implantation for prostate cancers has rapidly increased. Conclusions: These results advocate the continuation of the survey to demonstrate the developments in the field of brachytherapy.
PO81
PO83
FDG PET/CT in head and neck brachytherapy Annedore R. Strnad, M.D.1 Torsten Fritscher, M.D.2 Alexander Cavallaro, M.D.3 Matthias Geiger, M.D.1 Rolf Sauer, M.D.1 Vratislav Strnad, M.D.1 1 Radiation Oncology, University ErlangeneNuremberg, Erlangen, Germany; 2Nuclear Medicine, University ErlangeneNuremberg, Erlangen, Germany; 3University ErlangeneNuremberg, Erlangen, Germany.
History of Japan’s radioactive sources for brachytherapy Takashi Yamashita, M.D., Takayuki Nose, M.D., Yutaka Takahashi, Ph.D. Radiation Oncology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan.
Purpose: We studied the value of FDG PET/CT investigation for treatment planning in patients with head and neck cancer who were treated with interstitial brachytherapy alone. Methods and Materials: From 3/2007 e 10/2007 8 patients with tumors of the tongue or tumors of the floor of the mouth were investigated by FDG PET/CT before and one day after implantation of plastic tubes for interstitial brachytherapy. At the same time all patients received an MRI of the head. Results: 6/8 patients had tumors that showed an active glucose storing signal in FDG PET/CT before and one day after implantation of plastic tubes. In 50% of patients the active glucose storing signal did not correspond to clinical tumor extension. Comparison of MRI and FDG PET/CT showed correspondence in 5/8 cases, only. The SUVmax in the active glucose storing tumor regions was between 7.8 and 23.8 before implantation and between 5.6 and 15 one day after implantation. Comparing all FGD PET/CT investigations before and one day after implantation there was in 6 cases a systemic decrease in SUVmax in reference organs and a decrease in SUVmax in the tumor region. In 2 cases the systemic and local SUVmax stayed nearly the same.
Purpose: To review the history of radioisotopes for brachytherapy in Japan. Methods and Materials: All data were collected from the Japan Radioisotope Association (JRIA) and the Japanese Foundation of Cancer Research (JFCR). Results: Brachytherapy in Japan began at the Cancer Institute Hospital in 1939 at which time 5-gram radium sources were imported from Belgium. Soon afterwards other institutions and hospitals introduced radium sources for treatment of head and neck and skin cancers. Such sources were used for not only brachytherapy but also teletherapy. After World War II, the government set up JRIA to regulate isotopes for protecting medical workers and the general public from radiation hazard. Although a private institution, JRIA controlled all radioactive materials throughout Japan, even those for industrial purposes. In 1947, JFCR started to produce radon seeds for medical use. This source was used mainly for head and neck cancers between 1947 and 1975; JRIA also distributed this product to other Japanese hospitals. Low (LDR) and high (HDR) dose rates of iridium sources, distributed via JRIA, have been made at the Japanese Atomic Power Station since 1982. About 210,000 radon seeds were used during those three decades. The use of HDR Ir-192 sources has rapidly increased since 1986 in which year JRIA recommended the suspension of radium and LDR cobalt as treatment sources. Iodine-125 prostate permanent implant brachytherapy was begun in 2003 after prolonged
166
Abstracts / Brachytherapy 7 (2008) 91e194
negotiations with the government. About 6,880 prostate cancer patients in 79 hospitals have been treated by permanent seed treatment as of 2007. About 400,000 I-125 seeds were used in the most recent 5 years. Conclusions: The use of radioisotopes in brachytherapy in Japan has significantly changed in recent years. In particular, the number of sources in clinical use has rapidly increased in the past 70 years. Such data indicate that radiation safety and protection systems have become increasingly more important factors in cancer treatment in Japan. PO84 Role of high-dose-rate brachytherapy as palliative treatment for obstructive malignant jaundice G.C. Mattiucci1 E. Ippolito1 D. Smaniotto1 B. De Bari1 S. Luzi1 G. Mantini1 M. Mutignani2 V. Valentini1 G. Costamagna2 N. Cellini1 1 Radiation Oncology, Catholic University, Rome, Italy; 2Surgical Sciences, Catholic University, Rome, Italy. Purpose: Extrahepatic bile duct cancer is an uncommon disease often diagnosed at an advanced stage. The great majority of patients are not suitable for curative surgery. In this setting, the therapeutic goal is often palliative. Given a short life expectancy, the most feasible radiotherapy treatment should be the hypofractionated short course schedule, which can be performed either by external beam radiotherapy or high-dose-rate intraluminal brachytherapy (ILBT). The aim of this study is to evaluate the effectiveness of intraluminal brachytherapy in the treatment of obstructive malignant jaundice in terms of outcome and toxicity. Methods and Materials: Patients affected by extrahepatic biliary tract carcinoma, proven by biopsy, unsuitable to undergo surgery or radio chemotherapy because of age O80 years or comorbidities (value O8 according to score of Charlson 1994), were treated with ILBT alone delivered by transhepatic or endoscopic retrograde route. ILBT was performed using a high-activity 192Ir source (microSelectron remote afterloading system Nucletron). The radiation dose of the HDR-192Ir ILBT was prescribed at 10 mm from the center of the source with a single daily dose of 500 cGy to a total dose of 20e25 Gy given in four-five days. We evaluated the compliance of patients, the grade of toxicity according to RTOG scale and the median time of stent patency for each patient. Results: From May 2004 to June 2007 12 patients (7 females, 5 males) affected by extrahepatic cholangiocarcinoma (n 5 11) and ampulloma (n 5 1) were treated .The stage of disease at diagnosis was IA (n 5 1), IB (n 5 7), II A (n 5 2), III (n 5 2). Among the patients affected by cholangiocarcinoma, tumor location was as follows: hepatic duct bifurcation (n 5 2), common hepatic duct (n 5 2), common bile duct (n 5 6), hepatic duct bifurcation plus common bile duct (n 5 1). All patients before treatment had jaundice. ECOG performance status was 3 (n 5 4), 2 (n 5 3), 1 (n 5 4) and 0 (1). Eleven patients completed the treatment. In one patient the last application could not be performed due to the poor compliance of the patient. The median time of stent patency was 5 months (range: 3e20). Cholangitis occurred in 2 patients. One patient experienced hemobilia. No gastrointestinal bleeding was recorded. Median overall survival was 11 months (range 4e26). Conclusions: Hypofractionated short course schedule performed by transduodenal HDR-192Ir brachytherapy is feasible and represents a safe palliative therapy in treating malignant obstructive jaundice. Dose escalation prospective studies are expected also to investigate the potentiality of extending survival in these patients.
PO85 Intraoperative brachytherapy in the management of high-risk neck node metastasis: Two case reports from Rajiv Gandhi Cancer Institute Preeti Bagga, DNB1 Anil Kumar Anand, M.D.1 Pritam Singh Negi, FUICC2 Ram Kishan Munjal, M.Sc.2 Avtar Raina, M.D.1 Amal Roy Chaudhoory, M.D.1 Kapil Kumar, FICS.3 1Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India; 2Medical Physics, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India;
3
Surgical Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India. Purpose: To explore the feasibility of intraoperative brachytherapy boost in patients with neck node metastasis having poor prognostic features in combination with surgery and postoperative external beam radiotherapy. Methods and Materials: Two cases of neck node metastasis associated with extra capsular extension underwent radical neck dissection and intra operative brachytherapy to the tumor bed followed by external beam radiotherapy. A Freiberg applicator with six catheters was sutured to the pre-vertebral fascia during modified radical neck dissection. A 10 Gy dose was delivered intraoperatively. Subsequently the neck was treated with external radiation to a dose of 45 Gy in 24-fr. Results: At a median followup 21 months both patients were locally disease-free. The procedure was well tolerated and morbidity was minimal. One patient developed sensation at the site of surgery and both patients complained of grade II xerostomia (CTC version 3). Conclusions: For locally advanced and recurrent neoplasms, where local control is a major factor in patient outcome, IORT does provide a therapeutic edge when integrated with surgery and EBRT.
PHYSICS POSTERS SundayeTuesday May 4, 2008 e May 6, 2008 7:00 AMe6:00 PM PO86 Evaluation of 192Ir high-dose-rate rectal brachytherapy treatment plans using a fast Monte Carlo photon transport code Emily Poon, M.Sc.1 Jeffrey F. Williamson, Ph.D.2 Frank Verhaegen, Ph.D.1 1 Medical Physics, McGill University, Montreal, QC, Canada; 2Medical Physics, Radiation Oncology, Virginia Commonwealth University, Richmond, VA. Purpose: To retrospectively evaluate the treatment plans of a rectal cancer patient cohort who received 192Ir high-dose-rate (HDR) brachytherapy with a metal-shielded intracavitary mould applicator. Using fast Monte Carlo (MC) techniques, dose perturbations due to applicator and anatomical heterogeneities and their effects on the target dose coverage were examined. Methods and Materials: Forty rectal treatment plans generated from a TG43-based brachytherapy planning system (BPS) were re-calculated using PTRAN_CT, which is an extension of the well-benchmarked PTRAN photon transport code designed for accelerated patient dose calculations. An image-based treatment planning and analysis tool was developed with capabilities to efficiently extract patient data from the BPS and to enable MC calculations. In the MC simulations, scatter and attenuation in the applicator and the shielding were explicitly modeled. Patient materials and densities were assigned to 2x2x2 mm3 voxels according to CT data, with adjustments made to correctly identify bony structures, metal clips, and contrast medium. Additionally, a kernel superposition algorithm that makes use of PTRAN pre-generated dose kernels was implemented. This superposition approach accounts for applicator heterogeneities and has the same computational efficiency as the TG43 2D algorithm. The kernels have been validated using Gafchromic EBT film measurements in water. Results: Metal shielding provides significant tissue sparing for patients with non-circumferential tumors, and causes negligible dose perturbations on the unshielded side. Depending on the source loading configuration, 40% to 85% dose reduction to normal tissues can be achieved. However, the shielding also led to cold spots in 12 of the 40 patient plans. The V100 calculated using PTRAN_CT, kernel superposition, and TG43 2D algorithms were 94 5%, 94 5%, and 97 3%, respectively. Anatomical heterogeneities did not affect the target dose, while differences of 3% to 15% were found in bony structures and in regions behind air cavities. PTRAN_CT can achieve 2% uncertainty in a 29 cm3 target in 2.5 min, 4.1 min, and 6.6 min on a 2.8 GHz processor when using 40 40 40, 60 60 60, and 80 80 80 voxels, respectively. Conclusions: MC-based treatment planning is recommended for HDR rectal brachytherapy to achieve conformal dose distributions with sufficient target coverage, especially when metal shielding is used. Research sponsored by Nucletron BV.