Image-based lung functional radiotherapy planning for non-small cell lung cancer

Background This simulation study assessed the feasibility and impact of incorporating additional information from lung perfusion single-photon emission computed tomography (SPECT) into intensity-modulated radiotherapy planning for the treatment of non-small cell lung cancer (NSCLC). Methods In this simulation study, data of 13 patients with stage I-III NSCLC previously treated by radio(chemo)therapy were used. The SPECT was fused together with radiotherapy planning CT. Functional lung regions (FL) and non-functional lung regions (nFL) were defined based on SPECT images. Four treatment plans were created for each patient: an IMRT and a VMAT plan with planning CT (anatomical plans), and an IMRT and a VMATplan which integrate the additional information from lung perfusion scintigraphy (function plans). Dosimetric parameters were compared between all plans for PTV parameters and normal tissue preservation, focusing on optimizing the lung volume receiving at least 20Gy (V-20Gy). Results Compared to anatomical plans, functional IMRT and functional VMAT plans reduced functional lung V-20Gy in all cases of local and diffuse hypoperfusion patterns of SPECT defects. Similar results were observed for functional lung V-30Gy and median dose to functional lung D-mean, but were not statistically significant in any group. A significant increase in non-functional lung V-20Gy resulted in both functional plans. There were no significant differences in conformity or heterogeneity indices or PTV median doses between either pair of anatomical and functional plans. Conclusion The incorporation of functional imaging for radiotherapy planning in non-small cell lung cancer is feasible and appears to be beneficial in preserving a functional lung in non-small cell lung cancer.