Radiotherapy Oncology Department, IRCCS-CROB, Rionero in Vulture, Potenza, Italy.
Clin Transl Oncol. 2013 May;15(5):412-5. doi: 10.1007/s12094-012-0946-4. Epub 2012 Oct 13.
To evaluate the dosimetric changes of parotid glands (PG) during a course of intensity-modulated radiotherapy (IMRT) in head and neck (H&N) cancer patients.
Ten patients with H&N cancer treated by IMRT were analyzed. The original treatment plan (CT(plan)) was transferred to cone-beam computed tomography (CBCT) acquired at the 15th and 20th treatment day (CBCT(plan) I and II, respectively). The PG mean dose (D(mean)), the dose to 50 % of the volume, and the percent of volume receiving 30 and 50 Gy were measured by the dose volume histogram.
30 IMRT plans were evaluated (3 plans/patient). All dosimetric end points increased significantly for both PG only when CT(plan) was compared to CBCT(plan) I. The D(mean) increased significantly only for ipsilateral PG (p = 0.02) at week 3.
During a course of IMRT, CBCT is a feasible method to check the PG dosimetric variations. Perhaps, the 3rd week of radiotherapy could be considered as the time-check-point.
评估头颈部（H&N）癌症患者调强放疗（IMRT）过程中腮腺（PG）的剂量变化。
分析了 10 例接受 IMRT 治疗的 H&N 癌症患者。将原始治疗计划（CT（plan））转移到第 15 和第 20 天治疗时获取的锥形束 CT（CBCT（plan）I 和 II）上。通过剂量体积直方图测量 PG 的平均剂量（D（mean））、体积的 50%所受剂量以及接受 30 和 50 Gy 的体积百分比。
评估了 30 个 IMRT 计划（每个患者 3 个计划）。当将 CT（plan）与 CBCT（plan）I 进行比较时，仅 PG 的所有剂量学终点均显著增加。在第 3 周时，仅同侧 PG 的 D（mean）显著增加（p = 0.02）。
在 IMRT 过程中，CBCT 是检查 PG 剂量变化的一种可行方法。也许，放疗的第 3 周可以作为时间检查点。
