The time course of radiation therapy-induced reductions in regional perfusion: a prospective study with >5 years of follow-up.

Purpose: To assess the time-dependence of radiation therapy (RT)-induced reductions in regional lung perfusion, as measured by single photon emission computed tomography (SPECT) lung perfusion scans.

Methods And Materials: Between 1991 and 1999, 79 patients had SPECT lung perfusion scans before and serially after RT. Changes in regional perfusion were correlated with regional dose using 3D planning tools and image fusion (PLUNC-Plan UNC).