Delouya Guila, Bahary Pascal, Carrier Jean-François, Larouche Renée-Xavière, Hervieux Yannick, Béliveau-Nadeau Dominic, Donath David, Taussky Daniel
Department of Radiation Oncology, Centre hospitalier de l'Universiténde Montréal (CHUM), Hôpital Notre-Dame, Montreal, Canada; CRCHUM-Centre de recherche du Centre Hospitalier de l'Universiténde Montréal, Quebec, Canada.
Department of Radiation Oncology, Centre hospitalier de l'Universiténde Montréal (CHUM), Hôpital Notre-Dame, Montreal, Canada.
Brachytherapy. 2015 May-Jun;14(3):329-33. doi: 10.1016/j.brachy.2014.11.011. Epub 2015 Jan 24.
To analyze the difference in prostate coverage and dose to the rectum in men with prostate carcinoma treated with permanent seed brachytherapy with different seed activities.
Forty-nine patients treated with iodine-125 permanent seed prostate brachytherapy with low-activity seeds of 0.30-0.37 mCi were identified. For each of these patients, 2 patients with similar prostate volume (±2 cc) were paired: one treated with intermediate seed activity (0.44-0.46 mCi) and one with high seed activity (0.60-0.66 mCi). The doses to prostate and rectum were compared using CT on Day 30.
A total of 147 patients divided into the three seed activity groups were analyzed. Mean prostate volume was 35.7 cc (standard deviation [SD], 11.70). Compared with low-activity seeds, implants with high-activity seeds consisted of an average of 22 seeds and 4.7 needles less. The dose to the prostate (prostate volume receiving 100% of the prescribed dose [V100], prostate volume receiving 150% of the prescribed dose, and minimal dose covering 90% of the prostate volume expressed in Gy) was not higher on Day 30 (p = 0.58-0.97). The mean volume (in cubic centimeters) of rectal wall receiving 100% of the prescribed dose (V100) increased with activity: low activity, 0.34 cc (SD, 0.49), intermediate activity, 0.47 cc (SD, 0.48), and high activity, 0.72 cc (SD, 0.79) (p = 0.009). There was a trend (p = 0.073) toward a higher frequency of clinically unfavorable rectal dosimetry (V100 > 1.3 cc) in patients with high-activity seeds (16.7%) compared with low-activity (6.3%) or intermediate-activity (4.2%) seeds.
High-activity seeds do not result in a higher dose to the prostate but in a higher dose to the rectum.
分析不同活度的碘-125粒子永久植入近距离放射治疗前列腺癌患者时前列腺覆盖范围及直肠受量的差异。
纳入49例接受0.30 - 0.37 mCi低活度碘-125粒子永久植入前列腺近距离放射治疗的患者。为每例患者匹配2例前列腺体积相近（±2 cc）的患者：1例接受中等活度粒子（0.44 - 0.46 mCi）治疗，1例接受高活度粒子（0.60 - 0.66 mCi）治疗。在第30天使用CT比较前列腺和直肠的受量。
共分析了147例患者，分为三个粒子活度组。平均前列腺体积为35.7 cc（标准差[SD]，11.70）。与低活度粒子相比，高活度粒子植入的粒子平均少22颗，针数平均少4.7根。在第30天，前列腺受量（接受100%处方剂量的前列腺体积[V100]、接受150%处方剂量的前列腺体积以及以Gy表示的覆盖90%前列腺体积的最小剂量）并无更高（p = 0.58 - 0.97）。接受100%处方剂量（V100）的直肠壁平均体积（立方厘米）随活度增加：低活度为0.34 cc（SD，0.49），中等活度为0.47 cc（SD，0.48），高活度为0.72 cc（SD，0.79）（p = 0.009）。与低活度（6.3%）或中等活度（4.2%）粒子相比，高活度粒子患者中临床直肠剂量学不良（V100 > 1.3 cc）的频率有升高趋势（p = 0.073）。
高活度粒子不会使前列腺受量更高，但会使直肠受量更高。
