Optimal needle arrangement for intraoperative planning in permanent I-125 prostate implants Journal Article
| Authors: | Thompson, S. A.; Fung, A. Y. C.; Zaider, M. |
| Article Title: | Optimal needle arrangement for intraoperative planning in permanent I-125 prostate implants |
| Abstract: | One limitation of intraoperative planning of permanent prostate implants is that needles must already be in the gland before planning images are acquired. Improperly placed needles often restrict the capability of generating optimal seed placement. We developed guiding principles for the proper layout of needles within the treatment volume. The Memorial Sloan-Kettering Cancer Center planning system employs a genetic algorithm to find the optimal seed implantation pattern consistent with pre-assigned constraints (needle geometry, uniformity, conformity and the avoidance of high doses to urethra and rectum). Ultrasound volumes for twelve patients with I-125 implants were used to generate six plans per patient (total 72 plans) with different needle arrangements. The plans were evaluated in terms of V100 (percentage prostate volume receiving at least the prescription dose), U135 (percentage urethra volume receiving at least 135% of prescription dose), and CI (conformity index, the ratio of treatment volume to prescription dose volume.) The method termed POSTCTR, in which needles were placed on the periphery of the largest ultrasound slice and posterior central needles were placed as needed, consistently gave superior results for all prostate sizes. Another arrangement, labelled POSTLAT, where the needles were placed peripherally with additional needles in the posterior lateral lobes, also gave satisfactory results. We advocate two needle arrangements, POSTCTR and POSTLAT, with the former giving better results. |
| Keywords: | controlled study; implant; retrospective studies; treatment planning; united states; cancer radiotherapy; comparative study; radiation dose; methodology; sensitivity and specificity; quality control; cohort studies; image analysis; radiotherapy dosage; cohort analysis; patient monitoring; practice guideline; retrospective study; algorithms; prostatic neoplasms; prescription; cancer center; prostate; iodine 125; radioactive iodine; iodine radioisotopes; algorithm; evaluation; tumors; intraoperative period; prostate tumor; echography; brachytherapy; computer simulation; radiotherapy planning, computer-assisted; computer assisted radiotherapy; organ size; radiation dose distribution; needle; urethra; needles; planning; prostate carcinoma; prostate surgery; rectum; ultrasonics; glands; implants (surgical); genetic algorithms; humans; human; male; priority journal; article; syringes |
| Journal Title: | Physics in Medicine and Biology |
| Volume: | 47 |
| Issue: | 16 |
| ISSN: | 0031-9155 |
| Publisher: | IOP Publishing Ltd |
| Date Published: | 2002-08-21 |
| Start Page: | N209 |
| End Page: | N215 |
| Language: | English |
| DOI: | 10.1088/0031-9155/47/16/402 |
| PUBMED: | 12222865 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Export Date: 14 November 2014 -- Source: Scopus |
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