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Iodine‐125 thin seeds decrease prostate swelling during transperineal interstitial permanent prostate brachytherapy
Author(s) -
Beydoun Nadine,
Bucci Joseph A,
Chin Yaw S,
Malouf David
Publication year - 2014
Publication title -
journal of medical imaging and radiation oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 43
eISSN - 1754-9485
pISSN - 1754-9477
DOI - 10.1111/1754-9485.12102
Subject(s) - medicine , brachytherapy , prostate , prostate brachytherapy , dosimetry , urology , confidence interval , implant , nuclear medicine , ultrasound , radiation therapy , surgery , radiology , cancer
Prostate swelling following seed implantation is a well‐recognised phenomenon. The purpose of this intervention was to assess whether using thinner seeds reduces post‐implant swelling with permanent prostate brachytherapy. Methods Eighteen consecutive patients eligible for prostate seed brachytherapy underwent seed implantation using iodine‐125 ( I ‐125) thin seeds. Operative time, dosimetry, prostate swelling and toxicity were assessed and compared with standard I ‐125 stranded seed controls, sourced from the department's brachytherapy database. Results A learning curve was noted with the thin seeds in terms of greater bending and deviation of needles from their intended path. This translated into significantly longer total operative time (88 vs 103 minutes; P = 0.009, 95% confidence interval ( CI ) 4.1–24.3) and time per needle insertion (2.6 vs 3.7 minutes; P < 0.001, 95% CI 0.5–1.3) for the thin seeds. Day 30 prostate volumes were significantly smaller in the thin seed group compared with standard seeds (40.9 cc vs 46.8 cc; P = 0.001, 95% CI 1.5–5.6). The ratio of preoperative transrectal ultrasound to day 30 post‐implant CT volume was also smaller in the thin seed group (1.2 ± 0.1 for standard seeds vs 1.1 ± 0.1 for thin seeds). Post‐implant dosimetric parameters were comparable for both groups. No significant differences were seen in acute urinary morbidity or quality of life between the two groups. Conclusions I ‐125 thin seeds are associated with an initial learning curve, with longer operative time, even for experienced brachytherapists. The significant reduction in day 30 prostate volumes with the thin seeds has useful implications in terms of optimising dose coverage to the prostate in the early period post‐implantation, as well as improving the accuracy of post‐implant dosimetric assessments.