Roeske J C, Forman J D, Mesina C F, He T, Pelizzari C A, Fontenla E, Vijayakumar S, Chen G T
Department of Radiation and Cellular Oncology, University of Chicago, IL 60637, USA.
Int J Radiat Oncol Biol Phys. 1995 Dec 1;33(5):1321-9. doi: 10.1016/0360-3016(95)00225-1.
To document the size and location of the prostate, seminal vesicles, bladder, and rectum throughout the course of external beam radiotherapy. The frequency and range of motion of these organs are quantified.
Ten patients with localized carcinoma of the prostate had conventional simulation followed immediately by a treatment planning computed tomography scan (TPCT0). Once treatment was initiated, each patient had a weekly CT (TPCT1-N) before or after his daily treatment. Anatomical structures from CT were delineated on a computer workstation for analysis. The serial CT sets were spatially registered to the initial scan using image correlation software that brings into congruence the bony pelvis of the different scans. The location of the prostate, seminal vesicles, bladder, and rectum on subsequent scans were compared to TPCT0, as well as to each other.
Prostate volumes were observed to vary by an average of +/- 10% during the course of radiation therapy, while the seminal vesicle volumes varied by as much as 100%. Bladder and rectal volumes varied by +/- 30%. Compared to TPCT0, movement of the prostate was demonstrated in all patients. Quantitation of the center-of-mass (CM) showed motion of less than 1 mm in the left-right direction, while motion ranging from 0 to +/- 1 cm was observed in the anterior-posterior and superior-inferior directions. The individual standard deviations of these motions varied from approximately 1-5 mm. These variations were correlated to changes in the dimensions of the bladder and rectum.
Changes in the location of the prostate, seminal vesicles, and normal tissue volumes during the course of radiation therapy occur and have dosimetric consequences that may impact tumor control and normal tissue complication probabilities. Conformal therapy for prostate cancer will require the incorporation of knowledge of the anatomic relationships of these structures as a function of time. Therefore, these uncertainties must be taken into account when designing treatment plans and in considering dose escalation trials.
记录在体外束放射治疗过程中前列腺、精囊、膀胱和直肠的大小及位置。对这些器官的运动频率和范围进行量化。
10例局限性前列腺癌患者先进行常规模拟，随后立即进行治疗计划计算机断层扫描（TPCT0）。一旦开始治疗，每位患者在每日治疗前或后每周进行一次CT扫描（TPCT1 - N）。在计算机工作站上勾勒出CT图像中的解剖结构以进行分析。使用图像相关软件将系列CT数据集在空间上与初始扫描进行配准，该软件可使不同扫描的骨盆骨骼重合。将后续扫描中前列腺、精囊、膀胱和直肠的位置与TPCT0以及彼此进行比较。
在放射治疗过程中，观察到前列腺体积平均变化±10%，而精囊体积变化高达100%。膀胱和直肠体积变化±30%。与TPCT0相比，所有患者的前列腺均有移动。质心（CM）定量显示左右方向移动小于1 mm，而前后方向和上下方向观察到的移动范围为0至±1 cm。这些移动的个体标准差约为1 - 5 mm。这些变化与膀胱和直肠尺寸的变化相关。
放射治疗过程中前列腺、精囊和正常组织体积的位置发生变化，且具有剂量学后果，可能影响肿瘤控制和正常组织并发症概率。前列腺癌的适形治疗需要纳入这些结构的解剖关系随时间变化的知识。因此，在设计治疗计划和考虑剂量递增试验时必须考虑这些不确定性。
