Image guidance in proton therapy for lung cancer

Abstract

Proton therapy is a promising but challenging treatment modality for the management of lung cancer. The technical challenges are due to respiratory motion, low dose tolerance of adjacent normal tissue and tissue density heterogeneity. Different imaging modalities are applied at various steps of lung proton therapy to provide information on target definition, target motion, proton range, patient setup and treatment outcome assessment. Imaging data is used to guide treatment design, treatment delivery, and treatment adaptation to ensure the treatment goal is achieved. This review article will summarize and compare various imaging techniques that can be used in every step of lung proton therapy to address these challenges.

Proton versus photon radiation therapy: A clinical review

“…To mitigate these anatomic changes and motions, development and application of robust optimization methods ( 78 ), tracking/gating techniques or breath hold methods ( 79 , 80 ), in-room/real time image guidance (e.g. 4D-CT, cone-beam CT, MRI, optical surface monitoring system (OSMS)) ( 81 ) and in vivo range verification (e.g. positron emission tomography (PET), prompt gammas (PG) imaging) ( 82 , 83 ) are currently being investigated.…”

Adaptive planning and toxicities of uniform scanning proton therapy for lung cancer patients

“…Currently, of line adaption has been used at our center and most other proton centers, mainly because of lack of in room CT imaging, the long turnaround of manufacturing patient speci ic device such as apertures and compensators, and lack of better tools on QA plan generation and dose accumulation. However, pencil beam scanning has been a mainstream in newly constructed proton centers, in room cone beam CT or CT on rails are becoming available [12,15,19], and better tools are being developed in image registration, dose accumulation, and plan adaptation. These advancements would make online adaptation for proton therapy possible in the future.…”

“…Grade 3 occurrence was very rare Grade 3 and no Grade 4 toxicity was found. A clinical workfl ow of adaptive planning for lung cancer treatment using uniform scanning proton therapy (from Zheng [15]).…”

Online adaptive dose restoration in intensity modulated proton therapy of lung cancer to account for inter-fractional density changes

“…Bony-anatomy based rigid registration was performed between planning MidP-CTs and repeated MidP-CTs for patient positioning. Bony matching has been historically used in PT clinical routine to reproduce the relative position of bones with respect to protons [30] , [31] . Using the registration matrix, contours (isodoses, OARs and target) were mapped from the planning MidP-CT to the repeated MidP-CTs.…”