Weaver John, Harmon Grant, Harkenrider Matthew M, Surucu Murat, Wood Abbie, Alite Fiori, Small William
Department of Radiation Oncology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL.
Department of Radiation Oncology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL.
Brachytherapy. 2018 Jan-Feb;17(1):201-207. doi: 10.1016/j.brachy.2017.09.003. Epub 2017 Oct 21.
To define the relationship between the Point A prescription dose and the dose delivered to various pelvic lymph node groups during high-dose-rate (HDR) brachytherapy treatment of cervical cancer. In less developed countries, brachytherapy is often done without three-dimensional image guidance, instead relying on plain radiography and prescription to Point A. A defined relationship between Point A dose and lymph node doses would help physicians in these health care settings to more accurately estimate nodal doses.
Treatment data from 50 fractions of HDR brachytherapy of cervical cancer were reviewed, the pelvic lymph nodes were contoured, and dose-volume histogram parameters were obtained. Dose-volume histogram parameters for each contour were normalized as a percentage of the corresponding Point A dose. All nodal groups were divided into left and right sides, except the presacral nodal group.
Mean Point A doses were bilateral (Bil) 5.92 Gy ± 0.58, left (L) 5.93 ± 0.59, and right (R) 5.92 ± 0.59. Mean normalized D90 values for the various lymph node groups were as follows-obturator: Bil 20.3% ± 4.5, L 20.5% ± 4.4, and R 20.2% ± 5.2; external iliac: Bil 9.5% ± 2.9, L 10.0% ± 3.1, and R 9.5% ± 3.0; internal iliac: Bil 12.2% ± 3.5, L 12.1% ± 3.4, and R 12.9% ± 4.7; common iliac: Bil 4.3% ± 1.6, L 4.3% ± 1.6, and R 4.3% ± 1.7; and presacral: 8.7% ± 3.4. These relationships can serve as a useful tool for evaluating lymph node doses during HDR brachytherapy of cervical cancer in facilities performing two-dimensional treatment planning and those with limited resources.
确定宫颈癌高剂量率（HDR）近距离放射治疗期间A点处方剂量与传递至各盆腔淋巴结组的剂量之间的关系。在欠发达国家，近距离放射治疗通常在没有三维图像引导的情况下进行，而是依靠X线平片和A点处方。A点剂量与淋巴结剂量之间明确的关系将有助于这些医疗环境中的医生更准确地估计淋巴结剂量。
回顾了50次宫颈癌HDR近距离放射治疗的治疗数据，勾勒出盆腔淋巴结轮廓，并获得剂量体积直方图参数。每个轮廓的剂量体积直方图参数作为相应A点剂量的百分比进行归一化。除骶前淋巴结组外，所有淋巴结组均分为左侧和右侧。
平均A点剂量双侧（Bil）为5.92 Gy±0.58，左侧（L）为5.93±0.59，右侧（R）为5.92±0.59。各淋巴结组的平均归一化D90值如下：闭孔：双侧20.3%±4.5，左侧20.5%±4.4，右侧20.2%±5.2；髂外：双侧9.5%±2.9, 左侧10.0%±3.1，右侧9.5%±3.0；髂内：双侧12.2%±3.5，左侧12.1%±3.4，右侧12.9%±4.7；髂总：双侧4.3%±1.6，左侧4.3%±1.6，右侧4.3%±1.7；骶前：8.7%±3.4。这些关系可作为在进行二维治疗计划的机构和资源有限的机构中评估宫颈癌HDR近距离放射治疗期间淋巴结剂量的有用工具。
