Value of single-photon emission computed tomography perfusion lung scintigraphy in radiotherapy optimization for non-small cell lung cancer

Abstract

Objective To explore the relationship between functional dosimetric parameters of radiotherapy plans and radiation-induced lung injury using single-photon emission computed tomography (SPECT) perfusion lung scintigraphy, and to investigate the advantages of SPECT in optimizing radiotherapy plans. Methods From 2014 to 2015, 23 patients with non-small cell lung cancer (NSCLC) who received SPECT perfusion lung scintigraphy before radiotherapy were enrolled as subjects. The functional dose-volume histogram (fDVH) was generated and the relationship between fVx (the volume proportion of the functional lung tissue exposed to ≥x Gy of radiation in the whole functional lung tissue) and radiation-induced pneumonitis (RP) was explored. The radiotherapy plans were optimized based on SPECT and the dosimetric parameters were then compared between the optimized and conventional radiotherapy plans. The SPSS 13 software was used for chi-square test and receiver operating characteristic curve analysis. Comparison of DVH and fDVH between conventional and optimized radiotherapy plans was made by paired t test. Results The fV13 value for both lungs was most correlated with the incidence of grade ≥2 RP. The fV10, fV13, fV20, fV25, and fV40 values were significantly reduced and the conformity index was significantly improved after optimization (P=0.006, 0.007, 0.010, 0.036, 0.035, 0.040). Conclusions SPECT can be used to optimize radiotherapy plans. The fV13 value may be correlated with the incidence and severity of RP. Key words: Tomography, X-ray computed, single-photon emission; Pulmonary perfusion imaging; Radiation lung injury; Dose volume histogram