Initial analysis of Pro-Qura: A multi-institutional database of prostate brachytherapy dosimetry (original) (raw)
Related papers
American Journal of Clinical Oncology, 2008
To evaluate the influence of postimplant dosimetric timing on prostate brachytherapy quality in community practice. Materials and Methods: The Pro-Qura database was stratified by multiple time intervals between the implant and postimplant dosimetric analysis. Postimplant dosimetry was performed in a standardized fashion. Criteria for implant adequacy included V 100 Ͼ80%, D 90 Ͼ90%, and V 150 Ͻ60% for I-125 and Ͻ75% for Pd-103. Implants with V 100 Ͻ80% and D 90 Ͻ90% were deemed "too cool." Implants were considered "too hot" if D 90 Ͼ140% of prescription dose and/or V 150 Ͼ150% for I-125 and Ͼ75% for Pd-103. Results: For I-125, the average V 100 and D 90 increased from 88.6% to 89.8%, and 102.8% to 103.1% for day 0 and day 30 dosimetry. For Pd-103 implants the change was more pronounced, with V 100 and D 90 increasing from 81.6% to 87.8% (P Ͻ 0.001) and 88.7% to 100.0% (P Ͻ 0.001) for day 0, and day 30, respectively. The percentage of implants considered too cool based on a V 100 and D 90 criteria decreased from 18.8% and 26.9% on day 0 to 11.0% and 19.7% on day 30, respectively. Implants determined to be too hot based on a V 150 Ͼ60% (I-125)/Ͼ75% (Pd-103) or D 90 Ͼ140% were 16.4% and 2.2% on day 0 and 16.0% and 0.7% on day 30, respectively. Conclusion: In community-based brachytherapy programs, postimplant dosimetry performed at day 30 resulted in a statistically and clinically significant improvement in postimplant dosimetry compared with day 0. The influence of timing is substantially greater for Pd-103 than I-125. A B FIGURE 4. A, Percent of implants deemed too hot versus sequence group for I-125 cases. B, Percent of implants deemed too hot versus sequence group for Pd-103 cases.
Brachytherapy, 2013
PURPOSE: To evaluate a sector analysis program in the assessment and comparison of pre-and post-implant dosimetric parameters during the development of an 125 I permanent prostate brachytherapy service. METHODS AND MATERIALS: A total of 50 consecutive men being treated with permanent prostate brachytherapy had doseevolume analysis in 12 sectors of their pre-implant ultrasound (US pre ) and post-implant CT (CT post ) studies. Individual sectors were created by dividing prostate into three equal lengths, namely base, midgland, and apex. Each of these volumes was then divided into four axial sectors. Dosimetric parameters were compared in adjoining sectors within each study and between studies. RESULTS: There were statistically significant differences between individual sectors on US pre and CT post volumes with CT post higher than US pre ( p 5 0.001). Statistically significant differences were found in corresponding sectors on US pre and CT post for all dosimetric parameters. The dosimetric parameters were significantly lower on CT post in the anterior base and midgland ( p 5 0.001) and significantly higher at the posterior apex and midgland ( p 5 0.05). Dose homogeneity was demonstrated in adjoining sectors in all US pre and most adjoining sectors on CT post . CONCLUSIONS: Sector analysis allows rapid assessment of US pre and CT post dosimetry. It offers a scientific method of identifying areas of increased and reduced dosing on CT post when compared with US pre, providing a learning tool to refine dosimetric analysis and highlight sectors where implant quality could be improved. Ó
Potential role of various dosimetric quality indicators in prostate brachytherapy
International Journal of Radiation Oncology*Biology*Physics, 1999
Purpose: Postoperative CT-based dosimetric analysis provides detailed information regarding the coverage and uniformity of an implant, but the assessment of implant quality remains an unanswered and controversial issue. There is no disagreement that a good implant should cover the target volume with an adequate dose, but there is no consensus as to what represents an adequate dose. Materials and Methods: The American Brachytherapy Society has recently proposed that prostate brachytherapy quality be measured in terms of the following parameters: D90, V100, and V150 where D90 is defined as the minimal dose covering 90% of the prostate volume and V100 and V150 are defined as the percent volume of the prostate receiving at least 100% or 150% of the prescribed minimal peripheral dose (mPD), respectively. We report detailed day 0 dosimetric evaluation for 60 consecutive prostate brachytherapy patients implanted via a standard transperineal ultrasound guided approach in terms of D90, D100, V90, V100, and V150 and also the maximal and average rectal and urethral dose. Results: Dosimetric evaluation resulted in a V100 greater than 80% of the prostate volume and a D90 greater than 90% of the mPD in the entire patient population. There was a statistically significant difference between the quality scores of 125 I implants and 103 Pd implants with the 125 I mean V100 and D90 at 95.3% volume and 109.9% mPD, respectively, vs. 103 Pd at 91.8% volume and 103.7% mPD. Likewise, the rectal and urethral doses as a fraction of mPD were significantly lower in 103 Pd than in 125 I implants. This occurred despite the fact that palladium implants were typically preplanned with significantly better coverage and hotter V150 than iodine implants. We consider V150 to be an important parameter for determining dose homogeneity although the clinical utility of dose homogeneity remains unknown. The mean V150 was 45.6 ؎ 9.6% volume. There was no additional dosimetric utility from a determination of V90 while D100 was found to be overly sensitive to steep dose gradients at the periphery of the prostate. Conclusions: This report represents the first detailed postimplant day 0 dosimetric evaluation comparing ABS recommended quality parameters used to evaluate prostate brachytherapy. At the present time, no long-term clinical outcomes are available because of short follow-up. As PSA based follow-up data becomes available, however, this report may help define what represents an adequate implant.
Importance of Post-Implant Dosimetry in Permanent Prostate Brachytherapy
European Urology, 2002
Objective: Post-implant dosimetry has become the gold standard for implant evaluation and it is recommended that it be performed on all patients undergoing prostate brachytherapy. The technique, results and correlation with clinical outcomes will be presented. Methods: The method and outcomes of post-implant dosimetry are explored by outlining the experience at the Mount Sinai Medical Center, New York, as well as reviewing the literature. The most accurate time to perform postimplant dosimetry is 1 month after implant. Computed tomography (CT)-based dosimetry is currently the best available technique for performing this analysis. The technique involves taking 3-mm abutting CT slices throughout the implanted area. The prostate and normal structures are outline on the CT slices. These structures are recreated in three dimensions. Dose volume histograms (DVH) are created and allow the dose to these organs to be quanti®ed. Results: The relationship between dosimetric ®ndings and clinical outcomes has been established. The dose delivered to 90% of the prostate on DVH (D90) has been correlated to prostate-speci®c antigen (PCA) control and post-treatment biopsy results. D90 values of 140 Gy have been associated with improved biochemical control and lower positive post-treatment biopsy results. Doses derived from the dosimetric analysis to prostate, urethra and rectum have been correlated with the development of acute and chronic urinary morbidity, sexual potency and rectal morbidity. Future initiatives involve performing dosimetric calculations intraoperatively at the time of the implant. Conclusions: Post-implant CT-based dosimetry is an essential component of prostate brachytherapy. It is the only method of assessing the actual dose delivered to the prostate and normal surrounding structures. Future development in post-implant and intraoperative dosimetry will continue to improve permanent prostate brachytherapy as a safe an effective treatment for prostate cancer. # 2002 Published by Elsevier Science B.V.
Brachytherapy, 2013
We report on quality of dose delivery to target and normal tissues from low-dose-rate prostate brachytherapy using postimplantation dosimetric evaluations from a random sample of U.S. patients. METHODS AND MATERIALS: Nonmetastatic prostate cancer patients treated with external beam radiotherapy or brachytherapy in 2007 were randomly sampled from radiation oncology facilities nationwide. Of 414 prostate cancer cases from 45 institutions, 86 received low-dose-rate brachytherapy. We collected the 30-day postimplantation CT images of these patients and 10 test cases from two other institutions. Scans were downloaded into a treatment planning system and prostate/ rectal contours were redrawn. Dosimetric outcomes were reanalyzed and compared with calculated outcomes from treating institutions. RESULTS: Median prostate volume was 33.4 cm 3 . Reevaluated median V 100 , D 90 , and V 150 were 91.1% (range, 45.5e99.8%), 101.7% (range, 59.6e145.9%), and 53.9% (range, 15.7e88.4%), respectively. Low gland coverage included 27 patients (39%) with a D 90 lower than 100% of the prescription dose (PD), 12 of whom (17% of the entire group) had a D 90 lower than 80% of PD. There was no correlation between D 90 coverage and prostate volume, number of seeds, or implanted activity. The median V 100 for the rectum was 0.3 cm 3 (range, 0e4.3 cm 3 ). No outcome differences were observed according to the institutional strata. Concordance between reported and reevaluated D 90 values (defined as within AE10%) was observed in 44 of 69 cases. CONCLUSIONS: Central review of postimplantation CT scans to assess the quality of prostate brachytherapy is feasible. Most patients achieved excellent dosimetric outcomes, yet 17% had less than optimal target coverage by the PD. There was concordance between submitted target-coverage parameters and central dosimetric review in 64% of implants. These findings will require further validation in a larger cohort of patients. Ó
Variability of prostate brachytherapy preimplant dosimetry: A multi-institutional analysis
Brachytherapy, 2005
PURPOSE: To conduct a multi-institutional comparison of prostate brachytherapy preimplant dosimetry of Pd-103 and I-125. METHODS AND MATERIALS: Eight experienced brachytherapists submitted Pd-103 and I-125 monotherapeutic and boost preimplant dosimetry plans for central review. All 32 plans were calculated using the same transrectal ultrasound volumetric study. Seeds of any strength were acceptable, but were restricted to Theraseed Model 200 (Theragenics Inc., Buford, GA) and Oncura Oncoseed Model 6711 (Oncura, Plymouth Meeting, PA). The dosimetric analysis included evaluation of target volume, target to prostate ratio, target length, number of needles, seed activity, number of seeds, total activity, total activity divided by treatment planning volume, the use of extracapsular seeds, and average treatment margins (defined as the perpendicular distance between the prostate capsule and the 100% isodose line). Prostate coverage was defined in terms of V 100 /V 150 /V 200 /V 300 and D 100 /D 90 /D 50 , whereas urethral dosimetry consisted of UV 100 /UV 150 /UV 200 and UD 90 /UD 50 . RESULTS: The mean planning target volume to prostate volume ratio varied dramatically (mean 1.29, range 0.99-1.76) with the target length ranging from 3.5 to 4.5 cm. Although the prostate V 100 wasO95% in all cases, the V 150 ranged from 29.9% to 92.1% and the V 200 from 6.72% to 52.5%. The urethral V 100 was 100% in all cases with six of the eight brachytherapists limiting the UV 150 to!3%. However, the median urethral dose varied by up to 50%. Treatment margins also varied significantly (average 3.98 mm, range 0.32-7.68 mm). All brachytherapists used extracapsular seeds with five implanting O25% of the seeds in extracapsular locations (range 6.4-58.2%). In addition, significant variability existed in the number of needles, number of seeds, and seed strength. CONCLUSIONS: This study highlights the substantial variability that exists regarding target volume, seed strength, dose homogeneity, treatment margins, and extracapsular seed placement, although prostate brachytherapy prescription doses are uniform. The standardization of preimplant dosimetry is essential for meaningful multi-institutional comparisons of biochemical outcomes and morbidity. Ó
International Journal of Radiation Oncology*Biology*Physics, 2000
Objectives: Permanent implantation with 125 I in patients with localized prostate cancer who have prostate volumes > 50 cm 3 is often technically difficult owing to pubic arch interference. The objective of this study was to describe dosimetry outcomes in a group of patients who were implanted using the real-time ultrasound-guided technique who had prostate volumes > 50 cm 3. Materials and Methods: A total of 331 patients received an 125 I prostate seed implant from January 1, 1995, to June 1, 1999, of whom 66 (20%) had prostate volumes > 50 cm 3 at the time of the procedure. The real-time seed implant method was used in all patients and consisted of intraoperative planning and real-time seed placement using a combination of axial and sagittal ultrasound imaging. Pubic arch interference was managed using an extended lithotomy position or by angling the tip of the ultrasound probe in an anterior direction. No preimplant pubic arch CT scan study was performed and no patients were excluded from treatment because of prostate size. Implant quality was assessed using CT-based dosimetry performed 1 month postimplant. Dose-volume histograms for the prostate, bladder, rectum, and urethra volumes were generated. The target dose for these implants was 160 Gy and an adequate implant was defined as the dose delivered to 90% of the prostate (D90) > 140 Gy. The dose delivered to 95% of the prostate (D95) and doses to 30% of the rectal (DRECT30) and urethral (DURE30) volumes were also calculated. Results: Prostate volumes in the 66 patients ranged from 50 to 93 cm 3 (median 57, mean 61 cm 3). Total activity implanted was 27.8-89.1 mCi (median 57 mCi), with a range in activity per seed of 0.36-0.56 mCi (median 0.4 mCi). The prostate D90s and D95s ranged from 13,245 to 22,637 cGy (median 18,750) and 11,856 to 20,853 cGy (median 16,725), respectively. Only one patient (1.5%) had a D90 < 140 Gy. The DURE30 values ranged from 15,014 to 27,800 cGy (median 20,410) and the DRECT30 values were 3137-9910 cGy (median 5515). Conclusion: Implantation of the large prostate can be accomplished using the real-time method. A total of 98.5% of the patients receive a high-quality implant. In addition, these implants should not put patients at increased risk for significant urinary and bowel complications because urethral and rectal doses can be kept at acceptable levels.
Journal of medical imaging and radiation oncology, 2015
At present, post-implant CT-based dosimetry is a standard quality assurance practice following low dose rate (LDR) prostate brachytherapy. However, it rarely influences management and involves radiation exposure, costs and inconvenience. The purpose of our study was to assess the need for post-implant CT-based dosimetry through correlation with pre-implant and real-time dosimetry and review its place in the management of patients treated with LDR brachytherapy, so that it could be undertaken more selectively. The real-time dosimetry parameters of 34 consecutive patients who underwent LDR brachytherapy were compared with day 30 post-implant CT-based dosimetry. To validate our results against the world practice, we performed a meta-analysis of six relevant published studies, which combined data from 699 patients. The Student's t-test was performed to verify whether our dosimetric parameters significantly differ from the results of the meta-analysis. In our case series, the mean ta...
Radiotherapy and Oncology, 2004
Background and purpose: The purposes of this multicentric study are (a) the evaluation of four different commercially available treatment planning systems (TPSs) and (b) to verify whether the dosimetric results are comparable, also when considering the inter-observer variabilities and the different scanning protocols used. This work is to be considered a first step to test the value of multicentric studies based on dosimetric evaluation of the quality of the implants.
Brachytherapy, 2011
PURPOSE: To determine patients' self-reported experiences of outpatient high-dose-rate prostate brachytherapy boost, and compare with previous cohort treated as inpatients. METHODS AND MATERIALS: Using the Prostate Brachytherapy Questionnaire, we previously examined patients' subjective experience of the brachytherapy procedure when it involved one implant and hospitalization with the template in situ for 2 days (Group 1). The protocol was subsequently changed to two implants, 2 weeks apart as outpatients. Fifty-eight patients treated with the new protocol (Group 2) completed the same questionnaire. We compared the self-reported experiences between Groups 1 and 2 and also between the first and second implant for those in Group 2. Our hypothesis was that the worst rated issues in Group 1 might be reduced with the new approach. RESULTS: Group 2 patients were less troubled overall by the procedure (mean scores 2.3 vs. 3.2, p 5 0.0293). Specifically, they were less troubled by ''discomfort'' (2.8 vs. 3.8, p 5 0.0254); ''being stuck in bed'' (1.7 vs. 4.2 p!0.0001); ''feeling helpless'' (1.3 vs. 2.8, p 5 0.0009); ''fear of opening my bowels'' (2.1 vs. 3.3, p 5 0.0055); and ''fear of coping with the implant'' (1.3 vs. 2.5, p 5 0.0004). There was no significant increase in ''thought of implant'' or ''fear of implant'' before the second implant. However, more patients rated worse than expected ''fear of passing urine'' during the second implant. CONCLUSIONS: Patients rated high-dose-rate brachytherapy less troublesome when delivered as outpatient with two implants, 2 weeks apart than as inpatient over 3 days, despite the additional invasive procedure and anesthesia.