Functional Lung Avoidance SPECT-guided Radiation Therapy of Lung Cancer

This study is testing a radiation therapy technique called Functional Lung Avoidance, which uses special imaging (SPECT scans) to map which parts of the lung are actively working and then designs radiation treatment to spare those healthy, functioning areas. This approach aims to reduce lung damage and breathing problems caused by radiation in patients with lung cancer. **You may be eligible if you:** - Have been diagnosed with lung cancer (small-cell or non-small cell) - Are receiving radiation therapy with the goal of curing the cancer (curative intent) - Are 18 years of age or older - Have given informed consent **You may NOT be eligible if you:** - Are receiving concurrent immunotherapy alongside your radiation - Have had previous radiation treatment to the chest Talk to your doctor to see if this trial is right for you.