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Title: Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant

Abstract

A Monte Carlo (MC) study was carried out to evaluate the effects of the interseed attenuation and the tissue composition for two models of {sup 125}I low dose rate (LDR) brachytherapy seeds (Medi-Physics 6711, IBt InterSource) in a permanent breast implant. The effect of the tissue composition was investigated because the breast localization presents heterogeneities such as glandular and adipose tissue surrounded by air, lungs, and ribs. The absolute MC dose calculations were benchmarked by comparison to the absolute dose obtained from experimental results. Before modeling a clinical case of an implant in heterogeneous breast, the effects of the tissue composition and the interseed attenuation were studied in homogeneous phantoms. To investigate the tissue composition effect, the dose along the transverse axis of the two seed models were calculated and compared in different materials. For each seed model, three seeds sharing the same transverse axis were simulated to evaluate the interseed effect in water as a function of the distance from the seed. A clinical study of a permanent breast {sup 125}I implant for a single patient was carried out using four dose calculation techniques: (1) A TG-43 based calculation, (2) a full MC simulation with realistic tissues and seedmore » models, (3) a MC simulation in water and modeled seeds, and (4) a MC simulation without modeling the seed geometry but with realistic tissues. In the latter, a phase space file corresponding to the particles emitted from the external surface of the seed is used at each seed location. The results were compared by calculating the relevant clinical metrics V{sub 85}, V{sub 100}, and V{sub 200} for this kind of treatment in the target. D{sub 90} and D{sub 50} were also determined to evaluate the differences in dose and compare the results to the studies published for permanent prostate seed implants in literature. The experimental results are in agreement with the MC absolute doses (within 5% for EBT Gafchromic film and within 7% for TLD-100). Important differences between the dose along the transverse axis of the seed in water and in adipose tissue are obtained (10% at 3.5 cm). The comparisons between the full MC and the TG-43 calculations show that there are no significantdifferences for V{sub 85} and V{sub 100}. For V{sub 200}, 8.4% difference is found coming mainly from the tissue composition effect. Larger differences (about 10.5% for the model 6711 seed and about 13% for the InterSource{sup 125}) are determined for D{sub 90} and D{sub 50}. These differences depend on the composition of the breast tissue modeled in the simulation. A variation in percentage by mass of the mammary gland and adipose tissue can cause important differences in the clinical dose metrics V{sub 200}, D{sub 90}, and D{sub 50}. Even if the authors can conclude that clinically, the differences in V{sub 85}, V{sub 100}, and V{sub 200} are acceptable in comparison to the large variation in dose in the treated volume, this work demonstrates that the development of a MC treatment planning system for LDR brachytherapy will improve the dose determination in the treated region and consequently the dose-outcome relationship, especially for the skin toxicity.« less

Authors:
; ; ; ; ; ; ; ;  [1]
  1. Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada)
Publication Date:
OSTI Identifier:
22100515
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 36; Journal Issue: 5; Other Information: (c) 2009 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ADIPOSE TISSUE; BRACHYTHERAPY; COMPARATIVE EVALUATIONS; FILM DOSIMETRY; GYNECOLOGY; IMPLANTS; IODINE 125; LUNGS; MONTE CARLO METHOD; PROSTATE; RADIATION DOSES; THERMOLUMINESCENT DOSIMETRY

Citation Formats

Furstoss, C., Reniers, B., Bertrand, M. J., Poon, E., Carrier, J. -F., Keller, B. M., Pignol, J. P., Beaulieu, L., Verhaegen, F., Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec, H3G 1A4, Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Departement de Radio-Oncologie et Centre de Recherche du CHUM, Hopital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1, Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5, Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec G1R 2J6, and Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4. Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant. United States: N. p., 2009. Web. doi:10.1118/1.3116777.
Furstoss, C., Reniers, B., Bertrand, M. J., Poon, E., Carrier, J. -F., Keller, B. M., Pignol, J. P., Beaulieu, L., Verhaegen, F., Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec, H3G 1A4, Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Departement de Radio-Oncologie et Centre de Recherche du CHUM, Hopital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1, Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5, Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec G1R 2J6, & Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4. Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant. United States. https://doi.org/10.1118/1.3116777
Furstoss, C., Reniers, B., Bertrand, M. J., Poon, E., Carrier, J. -F., Keller, B. M., Pignol, J. P., Beaulieu, L., Verhaegen, F., Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec, H3G 1A4, Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Departement de Radio-Oncologie et Centre de Recherche du CHUM, Hopital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1, Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5, Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec G1R 2J6, and Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4. 2009. "Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant". United States. https://doi.org/10.1118/1.3116777.
@article{osti_22100515,
title = {Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant},
author = {Furstoss, C. and Reniers, B. and Bertrand, M. J. and Poon, E. and Carrier, J. -F. and Keller, B. M. and Pignol, J. P. and Beaulieu, L. and Verhaegen, F. and Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec, H3G 1A4 and Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 and Departement de Radio-Oncologie et Centre de Recherche du CHUM, Hopital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 and Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5 and Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, CHUQ Pavillon L'Hotel-Dieu de Quebec, 11 Cote du Palais, Quebec G1R 2J6 and Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4},
abstractNote = {A Monte Carlo (MC) study was carried out to evaluate the effects of the interseed attenuation and the tissue composition for two models of {sup 125}I low dose rate (LDR) brachytherapy seeds (Medi-Physics 6711, IBt InterSource) in a permanent breast implant. The effect of the tissue composition was investigated because the breast localization presents heterogeneities such as glandular and adipose tissue surrounded by air, lungs, and ribs. The absolute MC dose calculations were benchmarked by comparison to the absolute dose obtained from experimental results. Before modeling a clinical case of an implant in heterogeneous breast, the effects of the tissue composition and the interseed attenuation were studied in homogeneous phantoms. To investigate the tissue composition effect, the dose along the transverse axis of the two seed models were calculated and compared in different materials. For each seed model, three seeds sharing the same transverse axis were simulated to evaluate the interseed effect in water as a function of the distance from the seed. A clinical study of a permanent breast {sup 125}I implant for a single patient was carried out using four dose calculation techniques: (1) A TG-43 based calculation, (2) a full MC simulation with realistic tissues and seed models, (3) a MC simulation in water and modeled seeds, and (4) a MC simulation without modeling the seed geometry but with realistic tissues. In the latter, a phase space file corresponding to the particles emitted from the external surface of the seed is used at each seed location. The results were compared by calculating the relevant clinical metrics V{sub 85}, V{sub 100}, and V{sub 200} for this kind of treatment in the target. D{sub 90} and D{sub 50} were also determined to evaluate the differences in dose and compare the results to the studies published for permanent prostate seed implants in literature. The experimental results are in agreement with the MC absolute doses (within 5% for EBT Gafchromic film and within 7% for TLD-100). Important differences between the dose along the transverse axis of the seed in water and in adipose tissue are obtained (10% at 3.5 cm). The comparisons between the full MC and the TG-43 calculations show that there are no significantdifferences for V{sub 85} and V{sub 100}. For V{sub 200}, 8.4% difference is found coming mainly from the tissue composition effect. Larger differences (about 10.5% for the model 6711 seed and about 13% for the InterSource{sup 125}) are determined for D{sub 90} and D{sub 50}. These differences depend on the composition of the breast tissue modeled in the simulation. A variation in percentage by mass of the mammary gland and adipose tissue can cause important differences in the clinical dose metrics V{sub 200}, D{sub 90}, and D{sub 50}. Even if the authors can conclude that clinically, the differences in V{sub 85}, V{sub 100}, and V{sub 200} are acceptable in comparison to the large variation in dose in the treated volume, this work demonstrates that the development of a MC treatment planning system for LDR brachytherapy will improve the dose determination in the treated region and consequently the dose-outcome relationship, especially for the skin toxicity.},
doi = {10.1118/1.3116777},
url = {https://www.osti.gov/biblio/22100515}, journal = {Medical Physics},
issn = {0094-2405},
number = 5,
volume = 36,
place = {United States},
year = {Fri May 15 00:00:00 EDT 2009},
month = {Fri May 15 00:00:00 EDT 2009}
}