Effect and research progress of respiratory motion on intensity-modulated proton therapy / 中华放射肿瘤学杂志

Compared with intensity-modulated photon therapy, intensity-modulated proton therapy has significant dose advantages. However,the dose gradient of proton Bragg peak is relatively high,and the proton therapy is likely to be affected by range uncertainties,setup uncertainties and antonymic changes,etc. The difference between the planning dose and actual dose caused by respiratory motion hinders the widespread use of intensity-modulated proton therapy in thoracic cancers. In this paper,research progress on the effect of respiratory motion on intensity-modulated proton therapy and how to reduce the effect were summarized,aiming to provide reference for clinicians and researchers.

Preliminary clinical results after pencil beam scanning particle radiotherapy for stage Ⅰ non-small cell lung cancer / 中华放射医学与防护杂志

Objective To evaluate the safety and efficacy of proton and carbon-ion radiotherapy (RT) for stage Ⅰ non-small cell lung cancer (NSCLC) with pencil beam scanning technique.Methods From August 2014 to December 2015,10 patients with stage Ⅰ NSCLC who were inoperable or refused surgery were treated by proton +/-carbon-ion RT.Primary lesions were irradiated using 2-4 portals with 45-degree beams.A total dose of 50-70 GyE/10 fractions,60-64 GyE/15-16 fractions,and 66-72 GyE/22-24 fractions were administered to patients based on tumor location (4 peripheral,3 middle,and 3 central lesions,respectively).Results At the last follow-up in December 2016 with the median follow-up of 18.1 (11.9-28.1) months,local control was found in all patients per CT or PET/CT scanning(6 complete response,3 partial response,and 1 stable disease).However,2 patients with local control (1 partial response and 1 stable disease) experienced a distant failure at 8.7 and 24.9 months after RT,respectively.There was no RT-related Grade 3-5 toxicity in all patients.Grade 2 toxicities were only found in 2 patients (acute skin reaction and leucopenia,respectively).At 1,3-5 months after RT,the pulmonary function tests showed a slightly increase in FVC,FEV1 and DLCO-sb compared with those before RT without statistical significance (P ＞ 0.05).Conclusions The particle RT using pencil beam scanning technique was safe,and yielded encouraging outcome for patients with stage I NSCLC who were inoperable or refused surgery.Further follow-up and prospective clinical studies are warranted in the future.