An evaluation of three-field coplanar plans for conformal radiotherapy of prostate cancer
An evaluation of three-field coplanar plans for conformal radiotherapy of prostate cancer
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DOI：
10.1016/s0167-8140(00)00145-6
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发表时间：
2000-04-01
影响因子：
5.7
通讯作者：
Dearnaley, DP
中科院分区：
文献类型：
--
作者：
Khoo, VS;Bedford, JL;Dearnaley, DP
背景与目的：为确定前列腺放射治疗的最佳三场平面布置，研究了两种不同临床治疗体积，前列腺单（PO）和前列腺加精囊（PSV）的一系列共面三场布置。材料和方法：对10名患者的PO和PSV体积分别进行64和74 Gy的各种适形三场6 MV计划。为了便于描述，每个连续光束的方向以顺时针方式命名。计划包括系列安排0度，60-150度，210-300度；0度、90度、225-255度；90度，210-240度，300-330度和四场（4F）盒子计划进行比较。对680个方案进行比较，使用直肠体积辐照剂量大于规定剂量的50% （V-50）、80% （V-80）和90% (V-90)，直肠、膀胱和股骨头（FH）的正常组织并发症（NTCP）和肿瘤控制概率（TCP）。跳频容忍度设定为52 Gy至10%体积。结果：在比较PO组和PSV组34种不同的三持位构型时，门柱角分别为0度、90度和270度的三持位方案（PO：直肠V-80 = 22.8 +/- 5.5% (sd), V-90 = 18.4 +/- 5.7%， PSV：直肠V-80 = 41.9 +/- 5.8%, V-90 = 35.5 +/- 5.9%）可获得最大的八角保留。这也改善了4F-box方案（PO：直肠V-80 = 26.0 +/- 5.8%, V-90 = 21.4 +/- 5.2%, P < 0.001； PSV：直肠V-80 = 47.3 +/- 5.5%, V-90 = 41.6 +/- 5.1%, P < 0.001）。0度、120度、240度平面的直肠保留效果最差（PO：直肠V-80 = 35.2 +/- 8.0%, V-90 = 30.3 +/- 7.1%, P < 0.001； PSV：直肠V-80 = 65.7 +/- 9.0%, V-90 = 58.8 +/- 8.8%, P < 0.001）。在PO组中，使用0度、90度、270度方案，随着剂量从64 Gy增加到74 Gy，预测直肠NTCP的增加为3.3%，使用4F-box方案为4.7%，使用0度、120度、240度方案为6.9%。在PSV组中，0度、90度、270度方案、4F-box方案和0度、120度、240度方案的剂量增加分别使预测直肠NTCP增加了7.9、10.1和15.7%。结论：对于PO和PSV容积，0度、90度和270度三场方案在膀胱和股骨头剂量可接受的情况下均能最大限度地保留直肠。这个计划也改进了4F-box。与三场0度、120度、240度计划或4F-box计划相比，使用该计划，当剂量从64 Gy递增到74 Gy时，预测直肠NTCP的增加较小。(C) 2000爱思唯尔科学爱尔兰有限公司版权所有。
Background and purpose: A series of coplanar three-field configurations for two different clinical treatment volumes, prostate only (PO) and prostate plus seminal vesicles (PSV) were studied to determine the optimal three-field plan arrangement for prostate radiotherapy.Materials and methods: A variety of conformal three-field 6 MV plans prescribed to both 64 and 74 Gy were created for PO and PSV volumes in each of ten patients. For description, the orientation of each sequential beam was named in a clockwise fashion. Plans included series with arrangements of 0 degrees, 60-150 degrees, 210-300 degrees; 0 degrees, 90 degrees, 225-255 degrees; 90 degrees, 210-240 degrees, 300-330 degrees and a four-field (4F) box plan for comparison. Six-hundred and eighty plans were compared using the rectal volume irradiated to greater than 50% (V-50), 80% (V-80), and 90% (V-90) of the prescribed dose, normal tissue complications (NTCP) for rectum, bladder, and femoral heads (FH), and tumour control probabilities (TCP). FH tolerance was set at 52 Gy to 10% volume.Results: In comparing the 34 different three-held configurations for each of the PO and PSV groups, the greatest octal sparing was achieved by a three-held plan with gantry angles of 0 degrees, 90 degrees, 270 degrees (PO: rectal V-80 = 22.8 +/- 5.5% (1S.D.), V-90 = 18.4 +/- 5.7%, and PSV: rectal V-80 = 41.9 +/- 5.8%, V-90 = 35.5 +/- 5.9%). This also improved on the 4F-box plan (PO: rectal V-80 = 26.0 +/- 5.8%, V-90 = 21.4 +/- 5.2%, P < 0.001; and PSV: rectal V-80 = 47.3 +/- 5.5%, V-90 = 41.6 +/- 5.1%, P < 0.001). The worst rectal sparing was seen with the 0 degrees, 120 degrees, 240 degrees plan (PO: rectal V-80 = 35.2 +/- 8.0%, V-90 = 30.3 +/- 7.1%, P < 0.001; and PSV: rectal V-80 = 65.7 +/- 9.0%, V-90 = 58.8 +/- 8.8%, P < 0.001). In the PO group, the increase in predicted rectal NTCP with dose escalation from 64 to 74 Gy was 3.3% using the 0 degrees, 90 degrees, 270 degrees plan, 4.7% with the 4F-box plan, and 6.9% with the 0 degrees, 120 degrees, 240 degrees plan. In the PSV group, dose escalation increased the predicted rectal NTCP by 7.9, 10.1 and 15.7% for the 0, 90 degrees, 270 degrees plan, 4F-box plan, and 0 degrees, 120 degrees, 240 degrees plan, respectively.Conclusions: For both PO and PSV volumes, the three-field plan which afforded the greatest rectal sparing with acceptable bladder and femoral head doses was the 0 degrees, 90 degrees, 270 degrees plan. This plan also improved on the 4F-box. The increase in predicted rectal NTCP when escalating dose from 64 to 74 Gy was smaller using this plan compared to either the three-field 0 degrees, 120 degrees, 240 degrees plan or the 4F-box plan. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.