California Endocurietherapy at UCLA, Department of Radiation Oncology, David Geffen School of Medicine of the University of California at Los Angeles, Los Angeles, California 90095, USA.
Int J Radiat Oncol Biol Phys. 2013 Feb 1;85(2):543-8. doi: 10.1016/j.ijrobp.2012.03.035. Epub 2012 May 30.
We performed a dosimetry analysis to determine how well the goals for clinical target volume coverage, dose homogeneity, and normal tissue dose constraints were achieved with high-dose-rate (HDR) prostate brachytherapy.
Cumulative dose-volume histograms for 208 consecutively treated HDR prostate brachytherapy implants were analyzed. Planning was based on ultrasound-guided catheter insertion and postoperative CT imaging; the contoured clinical target volume (CTV) was the prostate, a small margin, and the proximal seminal vesicles. Dosimetric parameters analyzed for the CTV were D90, V90, V100, V150, and V200. Dose to the urethra, bladder, bladder balloon, and rectum were evaluated by the dose to 0.1 cm(3), 1 cm(3), and 2 cm(3) of each organ, expressed as a percentage of the prescribed dose. Analysis was stratified according to prostate size.
The mean prostate ultrasound volume was 38.7 ± 13.4 cm(3) (range: 11.7-108.6 cm(3)). The mean CTV was 75.1 ± 20.6 cm(3) (range: 33.4-156.5 cm(3)). The mean D90 was 109.2% ± 2.6% (range: 102.3%-118.4%). Ninety-three percent of observed D90 values were between 105 and 115%. The mean V90, V100, V150, and V200 were 99.9% ± 0.05%, 99.5% ± 0.8%, 25.4% ± 4.2%, and 7.8% ± 1.4%. The mean dose to 0.1 cm(3), 1 cm(3), and 2 cm(3) for organs at risk were: Urethra: 107.3% ± 3.0%, 101.1% ± 14.6%, and 47.9% ± 34.8%; bladder wall: 79.5% ± 5.1%, 69.8% ± 4.9%, and 64.3% ± 5.0%; bladder balloon: 70.3% ± 6.8%, 59.1% ± 6.6%, and 52.3% ± 6.2%; rectum: 76.3% ± 2.5%, 70.2% ± 3.3%, and 66.3% ± 3.8%. There was no significant difference between D90 and V100 when stratified by prostate size.
HDR brachytherapy allows the physician to consistently achieve complete prostate target coverage and maintain normal tissue dose constraints for organs at risk over a wide range of target volumes.
我们进行了剂量学分析，以确定在高剂量率（HDR）前列腺近距离放射治疗中，临床靶区覆盖、剂量均匀性和正常组织剂量限制的目标实现情况。
分析了 208 例连续接受 HDR 前列腺近距离放射治疗的植入物的累积剂量-体积直方图。计划基于超声引导的导管插入和术后 CT 成像；勾画的临床靶区（CTV）为前列腺、小边缘和近端精囊。对 CTV 进行了 D90、V90、V100、V150 和 V200 等剂量参数分析。通过对每个器官的 0.1cm3、1cm3 和 2cm3 剂量评估尿道、膀胱、膀胱球囊和直肠的剂量，并用规定剂量的百分比表示。分析按前列腺大小分层。
平均前列腺超声体积为 38.7±13.4cm3（范围：11.7-108.6cm3）。CTV 平均为 75.1±20.6cm3（范围：33.4-156.5cm3）。D90 平均值为 109.2%±2.6%（范围：102.3%-118.4%）。93%的观察到的 D90 值在 105 到 115%之间。V90、V100、V150 和 V200 的平均值分别为 99.9%±0.05%、99.5%±0.8%、25.4%±4.2%和 7.8%±1.4%。危险器官的 0.1cm3、1cm3 和 2cm3 剂量分别为：尿道：107.3%±3.0%、101.1%±14.6%和 47.9%±34.8%；膀胱壁：79.5%±5.1%、69.8%±4.9%和 64.3%±5.0%；膀胱球囊：70.3%±6.8%、59.1%±6.6%和 52.3%±6.2%；直肠：76.3%±2.5%、70.2%±3.3%和 66.3%±3.8%。按前列腺大小分层时，D90 与 V100 之间无显著差异。
HDR 近距离放射治疗可使医生在广泛的靶区体积范围内，始终实现完整的前列腺靶区覆盖，并保持危险器官的正常组织剂量限制。
