The first patient treatment of computed tomography ventilation functional image-guided radiotherapy for lung cancer

Background and purpose: Radiotherapy that selectively avoids irradiating highly-functional lung regions may reduce pulmonary toxicity. We report on the first clinical implementation and patient treatment of lung functional image-guided radiotherapy using an emerging technology, computed tomography (CT) ventilation imaging. Material and methods: A protocol was developed to investigate the safety and feasibility of CT ventilation functional image-guided radiotherapy. CT ventilation imaging is based on (1) deformable image registration of four-dimensional (4D) CT images, and (2) quantitative image analysis for regional volume change, a surrogate for ventilation. CT ventilation functional image-guided radiotherapy plans Were designed to minimize specific lung dose-function metrics, including functional V-20 (fV(20)), while maintaining target coverage and meeting standard constraints to other critical organs. Results: CT ventilation functional image-guided treatment planning reduced the lung fV(20) by 5% compared to an anatomic image-guided plan for an enrolled patient with stage IIIB non-small cell lung cancer. Although the doses to several other critical organs increased, the necessary constraints were all met. Conclusions: An emerging technology, CT ventilation imaging has been translated into the clinic and used in functional image-guided radiotherapy for the first time. This milestone represents an important first step toward hypothetically reduced pulmonary toxicity in lung cancer radiotherapy. (C) 2015 Elsevier Ireland Ltd. All rights reserved.