Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
Radiother Oncol. 2011 Sep;100(3):351-5. doi: 10.1016/j.radonc.2011.08.012. Epub 2011 Sep 6.
Density changes of healthy lung tissue during radiotherapy as observed by Cone Beam CT (CBCT) might be an early indicator of patient specific lung toxicity. This study investigates the time course of CBCT density changes and tests for a possible correlation with locally delivered dose.
A total of 665 CBCTs in 65 lung cancer patients treated with IMRT/VMAT to 60 or 66 Gy in 2 Gy fractions were analyzed. For each patient, CBCT lung density changes during the treatment course were related to the locally delivered dose.
A dose response is observed for the patient population at the end of the treatment course. However, the observed dose response is highly variable among patients. Density changes at 10th and 20th fraction are clearly correlated to those observed at the end of the treatment course.
CBCT density changes in healthy lung tissue during radiotherapy correlate with the locally delivered dose and can be detected relatively early during the treatment. If these density changes are correlated to subsequent clinical toxicity this assay could form the basis for biological adaptive radiotherapy.
通过锥形束 CT（CBCT）观察到的放疗过程中健康肺组织的密度变化可能是患者特定肺毒性的早期指标。本研究调查了 CBCT 密度变化的时间过程，并测试了与局部剂量的可能相关性。
对 65 例接受调强放疗/VMAT 治疗的肺癌患者的 665 次 CBCT 进行了分析，总剂量为 60 或 66Gy，分次剂量为 2Gy。对于每个患者，在治疗过程中 CBCT 肺密度变化与局部剂量相关。
在治疗结束时，观察到患者人群存在剂量反应。然而，患者之间的观察到的剂量反应差异很大。第 10 次和第 20 次分次的密度变化与治疗结束时观察到的密度变化明显相关。
放疗过程中健康肺组织的 CBCT 密度变化与局部剂量相关，并且可以在治疗过程中相对较早地检测到。如果这些密度变化与随后的临床毒性相关，那么该测定可以为生物适应性放疗奠定基础。
