[en] Purpose: To address glucose sensitivity in lung cancers before and after radiation treatment (Tx). Methods and Materials: Twelve patients were each studied with two pre-Tx positron emission tomography (PET) scans and 3 patients each with one post-Tx PET scan, with glucose concentration [Glc] and maximum standard uptake value (SUV) recorded. The pre-Tx glucose sensitivity, g from SUV₁/SUV₂ = {[Glc]₁/[Glc]₂}^g and Tx index, τ from SUV_post-Tx/SUV_pre-Tx = {[Glc]_post-Tx/[Glc]_pre-Tx}^τ was calculated by linear regression. Pre-Tx SUVs were corrected to post-Tx Glc with g (SUV'_pre-Tx) for a pure Tx effect, R ln(SUV_post-Tx/SUV'_pre-Tx). Results: There were no significant differences in SUV but [Glc] were different (96.4 ± 10.9 vs. 88.3 ± 10.5, p = 0.015) between two pre-Tx PET scans. Linear regression yielded g -0.79 and τ = -1.78 to -2.41 (p < 0.0005 in all). The %ΔSUV after Tx for 3 patients without vs. with g correction were different by -12%, 0%, and + 7%, suggesting varying effects from glucose. R values were also different and mean R (-0.81 ± 0.38) was significantly different from zero (p = 0.03), consistent with successful Tx as confirmed by clinico-radiologic follow-up. Conclusions: The extra dimension of glucose sensitivity, g besides SUV incorporated in the combined Tx-derived τ may be a useful global Tx evaluation index even with differing [Glc]