Dose and volume parameters for MRI-based treatment planning in intracavitary brachytherapy for cervical cancer
Dose and volume parameters for MRI-based treatment planning in intracavitary brachytherapy for cervical cancer
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DOI：
10.1016/j.ijrobp.2005.02.040
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发表时间：
2005-07-01
影响因子：
7
通讯作者：
Georg, D
中科院分区：
文献类型：
--
作者：
Kirisits, C;Pötter, R;Georg, D
目的：腔内近距离放射治疗中基于磁共振成像（MRI）的治疗计划允许逐个患者优化剂量分布。除了传统上使用的点剂量和体积参数，剂量体积直方图（DVH）分析使处方和报告的进一步的可能性。本研究报告的系统发展，我们的概念应用在clinical routine.Methods和材料：一组22例患者治疗93个分数使用串联环喷头和MRI为基础的个人治疗计划，每个应用程序进行了详细分析。勾画高风险临床靶体积和大体肿瘤体积。根据国际辐射单位和测量委员会（ICRU）报告38和DVH参数（例如，D-2cc代表照射最多的2 cm（3）的最小剂量。总剂量，包括外照射放射治疗和每个单个近距离放射治疗分次的值，被生物学标准化为传统的2-戈伊分次（α/β 10戈伊用于目标，3戈伊用于危险器官）。总处方剂量约为85戈伊主要采用45戈伊加4 × 7戈伊（共84戈伊（α β 10））。A点剂量（左，右）的平均值为82戈伊（α β 10），处方剂量的体积为84 cm（3）。临床靶体积的平均剂量为66戈伊（α β 10）（最小靶剂量），87戈伊（α β 10）（至少90%体积接受的剂量），平均体积至少接受89%的处方剂量治疗。膀胱的平均D-2cc为83戈伊（α β 3），ICRU点剂量为75戈伊（α β 3），ICRU点加颅侧1.5 cm处的剂量为100戈伊（α β 3）。D-2 cc直肠平均剂量为64戈伊（α β 3），ICRU点为69戈伊（α β 3）。σ D-2cc为63戈伊（α β 3）。结论：应使用标准装载模式作为基于MRI的优化的起点。主动驻留位置和驻留重量的个体变化由针对目标和危险器官的DVH约束的概念指导。在我们的临床常规中，A点的剂量和临床靶体积至少90%的体积所接受的剂量均与处方剂量相当。DVH对危险器官的限制允许可重复的治疗计划，有助于检测和避免严重的过量。(c)2005年爱思唯尔公司
Purpose: Magnetic resonance imaging (MRI)-based treatment planning in intracavitary brachytherapy allows optimization of the dose distribution on a patient-by-patient basis. In addition to traditionally used point dose and volume parameters, dose-volume histogram (DVH) analysis enables further possibilities for prescribing and reporting. This study reports the systematic development of our concept applied in clinical routine.Methods and Materials: A group of 22 patients treated with 93 fractions using a tandem-ring applicator and MRI-based individual treatment planning for each application was analyzed in detail. High-risk clinical target volumes and gross tumor volumes were contoured. The dose to bladder, rectum, and sigma was analyzed according to International Commission of Radiation Units and Measurements (ICRU) Report 38 and DVH parameters (e.g., D-2cc represents the minimal dose for the most irradiated 2 cm(3)). Total doses, including external beam radiotherapy and the values for each individual brachytherapy fraction, were biologically normalized to conventional 2-Gy fractions (alpha/beta 10 Gy for target, 3 Gy for organs at risk).Results: The total prescribed dose was about 85 Gy(alpha beta 10) which was mainly achieved by 45 Gy external beam radiotherapy plus 4 X 7 Gy brachytherapy (total 84 Gy(alpha beta 10)). The mean value was 82 Gy(alpha beta 10) for the point A dose (left, right) and 84 cm(3) for the volume of the prescribed dose. The average dose to the clinical target volume was 66 Gy(alpha beta 10) for the minimum target dose, 87 Gy(alpha beta 10) for the dose received by at least 90% of the volume, with a mean volume treated with at least the prescribed dose of 89%. The mean D-2cc for the bladder was 83 Gy(alpha beta 3) the ICRU point dose was 75 Gy(alpha beta 3) and the dose at the ICRU point plus 1.5 cm cranially was 100 Gy(alpha beta 3). The average dose to the rectum was 64 Gy(alpha beta 3) for D-2cc and at ICRU point 69 Gy(alpha beta 3). The sigma D-2cc was 63 Gy(alpha beta 3).Conclusion: A standard loading pattern should be used as the starting point for MRI-based optimization. Individual changes of active dwell positions and dwell weights are guided by a concept of DVH constraints for target and organs at risk. In our clinical routine, the dose to point A and dose received by at least 90% of the volume for the clinical target volume are both comparable to the prescribed dose. The DVH constraints for organs at risk allow reproducible treatment plans, helping to detect and avoid severe overdosage. (c) 2005 Elsevier Inc.