分次间变化对前列腺癌质子治疗和调强放射治疗效果的前瞻性比较
A Prospective Comparison of the Effects of Interfractional Variations on Proton Therapy and Intensity Modulated Radiation Therapy for Prostate Cancer.
作者信息
Moteabbed Maryam, Trofimov Alexei, Sharp Gregory C, Wang Yi, Zietman Anthony L, Efstathiou Jason A, Lu Hsiao-Ming
机构信息
Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
出版信息
Int J Radiat Oncol Biol Phys. 2016 May 1;95(1):444-453. doi: 10.1016/j.ijrobp.2015.12.366. Epub 2015 Dec 29.
PURPOSE
To quantify and compare the impact of interfractional setup and anatomic variations on proton therapy (PT) and intensity modulated radiation therapy (IMRT) for prostate cancer.
METHODS AND MATERIALS
Twenty patients with low-risk or intermediate-risk prostate cancer randomized to receive passive-scattering PT (n=10) and IMRT (n=10) were selected. For both modalities, clinical treatment plans included 50.4 Gy(RBE) to prostate and proximal seminal vesicles, and prostate-only boost to 79.2 Gy(RBE) in 1.8 Gy(RBE) per fraction. Implanted fiducials were used for prostate localization and endorectal balloons were used for immobilization. Patients in PT and IMRT arms received weekly computed tomography (CT) and cone beam CT (CBCT) scans, respectively. The planned dose was recalculated on each weekly image, scaled, and mapped onto the planning CT using deformable registration. The resulting accumulated dose distribution over the entire treatment course was compared with the planned dose using dose-volume histogram (DVH) and γ analysis.
RESULTS
The target conformity index remained acceptable after accumulation. The largest decrease in the average prostate D98 was 2.2 and 0.7 Gy for PT and IMRT, respectively. On average, the mean dose to bladder increased by 3.26 ± 7.51 Gy and 1.97 ± 6.84 Gy for PT and IMRT, respectively. These values were 0.74 ± 2.37 and 0.56 ± 1.90 for rectum. Differences between changes in DVH indices were not statistically significant between modalities. All volume indices remained within the protocol tolerances after accumulation. The average pass rate for the γ analysis, assuming tolerances of 3 mm and 3%, for clinical target volume, bladder, rectum, and whole patient for PT/IMRT were 100/100, 92.6/99, 99.2/100, and 97.2/99.4, respectively.
CONCLUSION
The differences in target coverage and organs at risk dose deviations for PT and IMRT were not statistically significant under the guidelines of this protocol.
目的
量化并比较分次治疗摆位误差和解剖结构变异对前列腺癌质子治疗（PT）和调强放射治疗（IMRT）的影响。
方法和材料
选取20例低危或中危前列腺癌患者，随机分为被动散射质子治疗组（n = 10）和调强放射治疗组（n = 10）。对于两种治疗方式，临床治疗计划均包括给予前列腺及近端精囊50.4 Gy（相对生物效应剂量），前列腺局部加量至79.2 Gy（相对生物效应剂量），每次分割剂量为1.8 Gy（相对生物效应剂量）。植入基准标记物用于前列腺定位，直肠内气囊用于固定。质子治疗组和调强放射治疗组患者分别每周接受计算机断层扫描（CT）和锥形束CT（CBCT）扫描。在每周的图像上重新计算计划剂量，进行缩放，并使用可变形配准映射到计划CT上。使用剂量体积直方图（DVH）和γ分析将整个治疗过程中得到的累积剂量分布与计划剂量进行比较。
结果
累积后靶区适形指数仍可接受。质子治疗和调强放射治疗中前列腺平均D98的最大降幅分别为2.2 Gy和0.7 Gy。平均而言，质子治疗和调强放射治疗中膀胱的平均剂量分别增加了3.26±7.51 Gy和1.97±6.84 Gy。直肠的这些值分别为0.74±2.37和0.56±1.90。两种治疗方式之间DVH指数变化的差异无统计学意义。累积后所有体积指数均保持在方案规定的公差范围内。假设公差为3 mm和3%，质子治疗/调强放射治疗的临床靶区、膀胱、直肠和全患者的γ分析平均通过率分别为100/100、92.6/99、99.2/100和97.2/99.4。
结论
在本方案的指导原则下，质子治疗和调强放射治疗在靶区覆盖和危及器官剂量偏差方面的差异无统计学意义。
Zotero 插件