Analysis of the Pro-Qura Database: Rectal dose, implant quality, and brachytherapist's experience
| Autor: | Christopher R. Loiselle, Gregory S. Merrick, John Sylvester, Peter Grimm, Wayne M. Butler, Musaddiq Waheed, Zachariah A. Allen, Steven Eulau |
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| Rok vydání: | 2009 |
| Předmět: |
Male
medicine.medical_treatment Brachytherapy Rectum Cohort Studies Iodine Radioisotopes Prostate medicine Humans Dosimetry Radiology Nuclear Medicine and imaging Radiometry Radioisotopes business.industry Prostatic Neoplasms Dose-Response Relationship Radiation medicine.anatomical_structure Oncology Rectal wall Implant business Nuclear medicine Postimplant dosimetry Palladium Prostate brachytherapy |
| Zdroj: | Brachytherapy. 8:34-39 |
| ISSN: | 1538-4721 |
| DOI: | 10.1016/j.brachy.2008.09.003 |
| Popis: | Purpose This study analyzed rectal dosimetry outcomes of Pro-Qura proctored implants to assess the achievability of proposed rectal dose constraints in the setting of standardized pre- and postimplant dosimetry in community-based brachytherapy programs. Methods and materials From August 2005 to July 2007, 713 postimplant CT scans were evaluated from 26 brachytherapists actively participating in Pro-Qura. Postimplant dosimetry was performed in a standardized fashion. The entirety of the rectal wall was contoured and evaluated for dose. Rectal dose was defined in terms of the volume of the rectum receiving 100% of the prescription dose ( R 100 ). Criteria for implant adequacy for both 103 Pd and 125 I included a prostate the percentage of the prostate volume covered by the prescription dose ( V 100 ) > 80%, a prostate the maximum dose covering 90% of the prostate volume ( D 90 ) of 90–140%, and an R 100 3 for early (Day 0–7) dosimetry and 3 for late (Day 20–45) dosimetry. Results Mean prostatic volume was 35.1 cm 3 . The mean time from implant to CT scan was 29.9 days (range, 0–45 days). The respective mean overall prostate V 100 and D 90 were 89% and 101%, respectively, and remained consistent for sequence groups 1 through 6. Overall, the mean R 100 was 0.97 ± 1.04 cm 3 . The R 100 was 1.15 cm 3 for sequence Group 1 and with each subsequent sequence group decreased with a nadir of 0.83 cm 3 in sequence Group 6 ( p = 0.22). Rectal dosimetry was deemed inadequate in 39% of Group 1 implants but only 22% in Group 6 ( p = 0.016). The reduced rectal doses did not impact prostate gland coverage. Conclusions Using standardized dosimetry, R 100 improved with increasing brachytherapist's experience, reaching a plateau after approximately 20 patients. |
| Databáze: | OpenAIRE |
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