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SU‐FF‐T‐171: Dosimetric Comparison of Cesium‐131 and Palladium‐103 for Permanent Prostate Brachytherapy
Author(s) -
Musmacher J,
Byrnes R,
Satchwill K,
Rumpf L
Publication year - 2007
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2760830
Subject(s) - brachytherapy , nuclear medicine , prostate , medicine , prostate brachytherapy , radiation treatment planning , palladium , urology , radiation therapy , surgery , chemistry , biochemistry , cancer , catalysis
Purpose: To evaluate the dosimetric differences in treatment planning between Cesium‐131 and Palladium‐103 in prostate brachytherapy. Introduction: Due to the short half‐life of Cesium‐131 and the energy emitted, when compared to Palladium‐103, planning guidelines must be established. This study focuses on seed count, dose to critical structures and homogenous dose distribution. Materials and Methods: Thirty patients were planned using Varian's Variseed 7.1, both with Palladium‐103 and Cesium‐131 for monotherapy, to a prescribed dose of 125Gy and 115 Gy respectively. The average gland size was 28.48 cc. All volumes were contoured and sources were placed using Palladium‐103 at an activity of 2.0u. Another treatment plan was developed using Cesium‐131 at an activity of 2.0u. All prostatic contours were identical between the two treatment plans for each patient. The following quantities were derived from each plan: total seed count, total needle count, D90, V150, V100, V90, V80, R100, and U10. Results: In the series, there was a decrease of 17.46% planned seeds (70 vs. 59) and 6% planned needles (18 vs. 17) when planning for Cesium‐131 as compared to Palladium‐103. There was a decrease in the V150 of 35.53% (39.31% for Cs131 vs. 60.97% for Pd103), while maintaining an average D90 of 115.46% for Cs131 and 115.29% for Pd103. There was a decrease in the R100 of 44.23% (0.15cc for Cs131 vs. 0.28cc for Pd103). A small decrease in U10 of 1.98% was also noted. Conclusion: Cesium‐131 as an alternative to Palladium‐103 for prostate brachytherapy is favorable in this study as it reduces the overall seeds and needles needed for implants while offering an improved homogeneous dose distribution; reducing the overall dose to the rectum and prostatic urethra. Further studies on these patients are in progress to assess the actual post‐implant dosimetry and morbidity associated with Cesium‐131.