Radiation-induced lung injuries (RILI) are a notable complication of thoracic radiotherapy, significantly affecting the quality of life and prognosis for cancer patients. We present the case of a 68-year-old man with metastatic prostate cancer who underwent radiation therapy for a metastatic thoracic vertebral lesion identified with high uptake on a PET-PSMA scan. Four months later, a follow-up PET-PSMA scan indicated that the pathological uptake in the vertebra had resolved, but it also revealed a new lung consolidation with PSMA uptake. This case illustrates a potential pitfall in interpreting PSMA PET-CT findings, as the uptake in the lung lesion was due to RILI rather than malignancy, infection, or another form of pneumonia, highlighting the necessity for careful clinical correlation to avoid misdiagnosis and potentially inappropriate and unnecessary treatment.