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Title: Multi-species prostate implant treatment plans incorporating {sup 192}Ir and {sup 125}I using a Greedy Heuristic based 3D optimization algorithm

Abstract

The goals of interstitial implant brachytherapy include delivery of the target dose in a uniform manner while sparing sensitive structures, and minimizing the number of needles and sources. We investigated the use of a multi-species source arrangement ({sup 192}Ir with {sup 125}I) for treatment in interstitial prostate brachytherapy. The algorithm utilizes an 'adjoint ratio', which provides a means of ranking source positions and is the criterion for the Greedy Heuristic optimization. Three cases were compared, each using 0.4 mCi {sup 125}I seeds: case I is the base case using {sup 125}I alone, case II uses 0.12 mCi {sup 192}Ir seeds mixed with {sup 125}I, and case III uses 0.25 mCi {sup 192}Ir mixed with {sup 125}I. Both multi-species cases result in lower exposure of the urethra and central prostate region. Compared with the base case, the exposure to the rectum and normal tissue increases by a significant amount for case III as compared with the increase in case II, signifying the effect of slower dose falloff rate of higher energy gammas of {sup 192}Ir in the tissue. The number of seeds and needles decreases in both multi-species cases, with case III requiring fewer seeds and needles than case II. Further,more » the effect of {sup 192}Ir on uniformity was investigated using the 0.12 mCi {sup 192}Ir seeds in multi-species implants. An increase in uniformity was observed with an increase in the number of 0.12 mCi {sup 192}Ir seeds implanted. The effects of prostate size on the evaluation parameters for multi-species implants were investigated using 0.12 mCi {sup 192}Ir and 0.4 mCi {sup 125}I, and an acceptable treatment plan with increased uniformity was obtained.« less

Authors:
; ; ;  [1];  [2];  [2];  [2]
  1. Department of Engineering Physics and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20951036
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 34; Journal Issue: 2; Other Information: DOI: 10.1118/1.2400827; (c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ALGORITHMS; BRACHYTHERAPY; CARCINOMAS; DOSIMETRY; EVALUATION; IODINE 125; IRIDIUM 192; OPTIMIZATION; PROSTATE; RADIATION DOSES; RADIATION SOURCE IMPLANTS; RECTUM; URINARY TRACT

Citation Formats

Chaswal, V., Yoo, S., Thomadsen, B. R., Henderson, D. L., Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, Department of Engineering Physics, Department of Medical Physics, University of Wisconsin-Madison, and Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin 53706, and Department of Engineering Physics and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706. Multi-species prostate implant treatment plans incorporating {sup 192}Ir and {sup 125}I using a Greedy Heuristic based 3D optimization algorithm. United States: N. p., 2007. Web. doi:10.1118/1.2400827.
Chaswal, V., Yoo, S., Thomadsen, B. R., Henderson, D. L., Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, Department of Engineering Physics, Department of Medical Physics, University of Wisconsin-Madison, and Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin 53706, & Department of Engineering Physics and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706. Multi-species prostate implant treatment plans incorporating {sup 192}Ir and {sup 125}I using a Greedy Heuristic based 3D optimization algorithm. United States. doi:10.1118/1.2400827.
Chaswal, V., Yoo, S., Thomadsen, B. R., Henderson, D. L., Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, Department of Engineering Physics, Department of Medical Physics, University of Wisconsin-Madison, and Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin 53706, and Department of Engineering Physics and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706. Thu . "Multi-species prostate implant treatment plans incorporating {sup 192}Ir and {sup 125}I using a Greedy Heuristic based 3D optimization algorithm". United States. doi:10.1118/1.2400827.
@article{osti_20951036,
title = {Multi-species prostate implant treatment plans incorporating {sup 192}Ir and {sup 125}I using a Greedy Heuristic based 3D optimization algorithm},
author = {Chaswal, V. and Yoo, S. and Thomadsen, B. R. and Henderson, D. L. and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Engineering Physics, Department of Medical Physics, University of Wisconsin-Madison, and Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin 53706 and Department of Engineering Physics and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706},
abstractNote = {The goals of interstitial implant brachytherapy include delivery of the target dose in a uniform manner while sparing sensitive structures, and minimizing the number of needles and sources. We investigated the use of a multi-species source arrangement ({sup 192}Ir with {sup 125}I) for treatment in interstitial prostate brachytherapy. The algorithm utilizes an 'adjoint ratio', which provides a means of ranking source positions and is the criterion for the Greedy Heuristic optimization. Three cases were compared, each using 0.4 mCi {sup 125}I seeds: case I is the base case using {sup 125}I alone, case II uses 0.12 mCi {sup 192}Ir seeds mixed with {sup 125}I, and case III uses 0.25 mCi {sup 192}Ir mixed with {sup 125}I. Both multi-species cases result in lower exposure of the urethra and central prostate region. Compared with the base case, the exposure to the rectum and normal tissue increases by a significant amount for case III as compared with the increase in case II, signifying the effect of slower dose falloff rate of higher energy gammas of {sup 192}Ir in the tissue. The number of seeds and needles decreases in both multi-species cases, with case III requiring fewer seeds and needles than case II. Further, the effect of {sup 192}Ir on uniformity was investigated using the 0.12 mCi {sup 192}Ir seeds in multi-species implants. An increase in uniformity was observed with an increase in the number of 0.12 mCi {sup 192}Ir seeds implanted. The effects of prostate size on the evaluation parameters for multi-species implants were investigated using 0.12 mCi {sup 192}Ir and 0.4 mCi {sup 125}I, and an acceptable treatment plan with increased uniformity was obtained.},
doi = {10.1118/1.2400827},
journal = {Medical Physics},
number = 2,
volume = 34,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}