Tran Angelia, Zhang Jingjing, Woods Kaley, Yu Victoria, Nguyen Dan, Gustafson Gary, Rosen Lane, Sheng Ke
Department of Radiation Oncology, University of California, Los Angeles, 200 Medical Plaza Way, Suite B265, Los Angeles, CA, 90095, USA.
Department of Radiation Oncology, Beaumont Health System, Royal Oak, USA.
Radiat Oncol. 2017 Jan 11;12(1):10. doi: 10.1186/s13014-016-0761-0.
Intensity-modulated proton therapy (IMPT), non-coplanar 4π intensity-modulated radiation therapy (IMRT), and volumetric-modulated arc therapy (VMAT) represent the most advanced treatment methods based on heavy ion and X-rays, respectively. Here we compare their performance for prostate cancer treatment.
Ten prostate patients were planned using IMPT with robustness optimization, VMAT, and 4π to an initial dose of 54 Gy to a clinical target volume (CTV) that encompassed the prostate and seminal vesicles, then a boost prescription dose of 25.2 Gy to the prostate for a total dose of 79.2 Gy. The IMPT plans utilized two coplanar, oblique scanning beams 10° posterior of the lateral beam positions. Range uncertainties were taken into consideration in the IMPT plans. VMAT plans used two full, coplanar arcs to ensure sufficient PTV coverage. 4π plans were created by inversely selecting and optimizing 30 beams from 1162 candidate non-coplanar beams using a greedy column generation algorithm. CTV doses, bladder and rectum dose volumes (V40, V45, V60, V65, V70, V75, and V80), R100, R50, R10, and CTV homogeneity index (D95/D5) were evaluated.
Compared to IMPT, 4π resulted in lower anterior rectal wall mean dose as well as lower rectum V40, V45, V60, V65, V70, and V75. Due to the opposing beam arrangement, IMPT resulted in significantly (p < 0.05) greater femoral head doses. However, IMPT plans had significantly lower bladder, rectum, and anterior rectal wall max dose. IMPT doses were also significantly more homogeneous than 4π and VMAT doses.
Compared to the VMAT and 4π plans, IMPT treatment plans are superior in CTV homogeneity and maximum point organ-at-risk (OAR) doses with the exception of femur heads. IMPT is inferior in rectum and bladder volumes receiving intermediate to high doses, particularly to the 4π plans, but significantly reduced low dose spillage and integral dose, which are correlated to secondary cancer for patients with expected long survival. The dosimetric benefits of 4π plans over VMAT are consistent with the previous publication.
调强质子治疗（IMPT）、非共面4π调强放射治疗（IMRT）和容积调强弧形治疗（VMAT）分别代表了基于重离子和X射线的最先进治疗方法。在此，我们比较它们在前列腺癌治疗中的性能。
对10例前列腺癌患者分别采用具有稳健性优化的IMPT、VMAT和4π计划进行治疗，初始剂量为54 Gy，照射临床靶区（CTV），该靶区包括前列腺和精囊，然后对前列腺追加25.2 Gy的处方剂量，总剂量达79.2 Gy。IMPT计划使用两个共面、倾斜的扫描束，位于侧束位置后方10°。IMPT计划考虑了射程不确定性。VMAT计划使用两个完整的共面弧形，以确保对计划靶区（PTV）有足够的覆盖。4π计划通过使用贪婪列生成算法从1162个候选非共面束中反向选择和优化30个束来创建。评估CTV剂量、膀胱和直肠的剂量体积（V40、V45、V60、V65、V70、V75和V80）、R100、R50、R10以及CTV均匀性指数（D95/D5）。
与IMPT相比，4π治疗使直肠前壁平均剂量以及直肠的V40、V45、V60、V65、V70和V75更低。由于射束排列相反，IMPT导致股骨头剂量显著更高（p < 0.05）。然而，IMPT计划的膀胱、直肠和直肠前壁最大剂量显著更低。IMPT的剂量也比4π和VMAT的剂量显著更均匀。
与VMAT和4π计划相比，IMPT治疗计划在CTV均匀性和最大点危及器官（OAR）剂量方面表现更优，但股骨头除外。IMPT在接受中高剂量的直肠和膀胱体积方面表现较差，尤其是与4π计划相比，但显著减少了低剂量溢出和积分剂量，这与预期长期生存患者的继发癌症相关。4π计划相对于VMAT的剂量学优势与之前的出版物一致。
