Background/Objectives: Accurate assessment of pulmonary function is essential before planning radical lung cancer treatment. While spirometry reflects global lung function, perfusion imaging provides detailed information on regional perfusion patterns. This study aimed to characterize the pre-treatment profile of patients and compare the impact of surgical resection, radiotherapy, and thermal ablation on global pulmonary function and regional perfusion using SPECT/CT. Methods: In this prospective study of 68 patients, pre- and post-treatment assessments were conducted using lung perfusion SPECT/CT. While the entire cohort underwent imaging, longitudinal global pulmonary function (spirometry and gas diffusion) was analyzed for 45 patients who completed the three-month follow-up. Quantitative analysis included perfusion percentages and lung volumes, while a semi-quantitative scoring system evaluated the severity of perfusion defects. Results: In the overall cohort, the affected lung perfusion and volume significantly decreased (p = 0.002). Subgroup analysis revealed that the surgical resection group experienced significant reductions in perfusion (from 54.0% to 41.0%, p = 0.002) and volume (p < 0.001) of the affected lung, whereas no statistically significant changes were observed in the thermal ablation and radiotherapy groups (p > 0.05). Notably, 60.3% of patients presented with perfusion defects before treatment. Post-treatment spirometry parameters, particularly FEV1% (threshold 83.5%, AUC = 0.783), served as reliable predictors of persistent perfusion impairment. Conclusions: Radiotherapy and thermal ablation are lung-perfusion-sparing treatments compared to surgical resection. The high prevalence of pre-existing perfusion defects emphasizes the importance of incorporating lung perfusion SPECT/CT into routine pre-treatment evaluation to optimize treatment selection.

PSMA PET/CT imaging biomarkers are increasingly investigated as predictors of response and survival outcomes following [¹⁷⁷Lu]Lu-PSMA radioligand therapy in prostate cancer. This review summarizes the current evidence and clinical relevance of these biomarkers. As [¹⁷⁷Lu]Lu-PSMA radioligand therapy is increasingly being introduced into earlier treatment lines of prostate cancer management, the identification of reliable imaging biomarkers for response prediction and outcome assessment is becoming increasingly important. Quantitative PSMA PET/CT parameters such as whole-body (WB) mean standardized uptake value (SUV_mean), WB PSMA-positive tumor volume, and tumor load, as well as qualitative features including disease distribution and phenotype (e.g., visceral metastases and FDG-avid, PSMA-negative discordant lesions), have been associated with treatment response, progression-free survival, and overall survival. However, the clinical utility of these imaging biomarkers is limited by heterogeneous study designs, small cohorts, and a lack of standardization in image acquisition, quantification, and cutoff definitions. This review critically appraises available data on baseline PSMA PET/CT-based prognostic and potentially predictive biomarkers for RLT and identifies the methodological barriers that must be addressed before these biomarkers can be implemented in clinical practice.