The spatial similarity between Bleomycin order the submitted and reference expert prostate

contours was assessed using a Dice’s coefficient (9). The median prostate volume was 33.4 cm3 (range, 19.4–70.1 cm3). The median %V100, %D90, and %V150 were 91.1% (range, 45.5–99.8%), 101.7% (range, 59.6–145.9%), and 53.9% (range, 15.7–88.4%), respectively. Low gland coverage was observed in some patients: 27 (39%) were noted to have a D90 lower than 100% of PD; and of those, 12 (17%) had a D90 lower than 80% of the PD. For this data set, there was no correlation between D90 coverage and prostate volume, number of seeds, or total implanted activity. In addition, there were no apparent differences in D90 dose coverage according to the different institutional strata. The median V100 for the rectum was 0.3 cc see more (range, 0–4.3 cc). The median D2cc rectum doses were 64.3% (range, 27.3–126.1%). No differences were observed in terms of dosimetric outcomes according to the institutional strata. The Dice’s coefficient was used to compare the submitted and reviewed prostate volumes, as shown in Fig. 1. The coefficient measures the intersection between the two volumes to be compared; thus a Dice’s coefficient of 1 means that the two volumes can be superimposed and are equal. The average Dice’s coefficient for the prostate volumes

in these patients was 0.83 (range, 0.75–0.92) with a standard deviation (SD) of 0.04. The median and SD of %D90 for the submitted and reviewed scans were 101.5% (SD, 17.6%) and 101.1% (SD, 18.5%), respectively ( Fig. 2). We define D90 concordance to be good if the D90 value reported by the treating institution is within 10% of the reevaluated D90. Good D90 concordance

was observed in 44 of the 69 cases. The median and SD of %V100 for the Ribose-5-phosphate isomerase submitted and reviewed scans were 88.1% (SD, 10.7%) and 87.9% (SD, 11.2%), respectively. For the submitted contours and calculated doses, there were 32 patients (46%) with D90 lower than 100% of the PD and 18 patients (26%) with D90 lower than 90% of the PD. When these contours were centrally reviewed and doses were recalculated, 28 patients (41%) were noted to have a D90 lower than 100% of the PD and 17 patients (25%) had a D90 lower than 90% of the PD. Figure 3 illustrates the similarities between the submitted and reviewer evaluations for %V150. As demonstrated in Fig. 3, 4% and 7% of patients had V150 greater than 80%, suggestive of a “hot implant” based on the submitted and centrally reviewed dose calculations. The average Dice’s coefficient for the rectal volumes in these patients was 0.8369 (range, 0.7533–0.9165) with an SD of 0.0431. The median and SD of rectal D2cc as a percentage of the PD was 62.7% (SD, 18.1) and 64.3% (SD, 20.3) for the submitted and reviewed scans, respectively ( Fig. 4). When all the above-mentioned analyses were performed excluding the 10 test cases, the findings were found to be not significantly different (data not shown).