Provision CARES Proton Therapy Center, Knoxville, Tennessee, USA.
J Appl Clin Med Phys. 2022 Feb;23(2):e13491. doi: 10.1002/acm2.13491. Epub 2021 Dec 10.
It is well known in proton therapy that the relative biological effectiveness (RBE) is not constant across the entire Bragg peak, with higher RBE at the distal end of the Bragg peak due to higher linear energy transfer (LET). Treatment planning systems are moving toward LET optimization to mitigate this potentially higher biological impact at a track end. However, using a simple script, proton users can begin to simulate this process by deleting spots from critical structures during optimization. In most cases, nominal target coverage and plan robustness remain satisfactory.
In our clinic, we developed a script that allows the user to delete spots in all organs at risk (OARs) of interest for one or more treatment beams. The purpose of this script is to potentially reduce side effects by eliminating Bragg peaks within OARs. The script was first used for prostate patients where spots in the rectum and sigmoid, outside of the overlap with the target, were deleted. We then began to use the script for head and neck (H&N) and breast/chestwall patients to reduce acute side effects of the skin by removing spots in a 0.5-cm skin rind.
By utilizing a simple script for deleting spots in critical structures, we have seen excellent clinical results thus far. We have noted reduced skin reactions for nearly all H&N and breast patients.
在质子治疗中，众所周知相对生物效应（RBE）并非在整个布拉格峰中保持不变，由于较高的线性能量传递（LET），布拉格峰的远端 RBE 更高。治疗计划系统正在朝着 LET 优化的方向发展，以减轻在轨道末端可能更高的生物学影响。然而，质子使用者只需使用一个简单的脚本，就可以通过在优化过程中从关键结构中删除点来开始模拟这个过程。在大多数情况下，名义上的目标覆盖率和计划稳健性仍然令人满意。
在我们的诊所，我们开发了一个脚本，允许用户为一个或多个治疗束删除所有感兴趣的危及器官（OAR）中的点。该脚本的目的是通过消除 OAR 内的布拉格峰来潜在地减少副作用。该脚本首先用于前列腺患者，在目标重叠之外的直肠和乙状结肠中删除点。然后，我们开始将脚本用于头颈部（H&N）和乳房/胸壁患者，通过去除 0.5 厘米的皮肤边缘中的点来减少皮肤的急性副作用。
通过使用一个简单的脚本从关键结构中删除点，我们迄今为止已经看到了出色的临床结果。我们注意到几乎所有 H&N 和乳房患者的皮肤反应都有所减轻。
