Regional thoracic dose assessment and experimental TLD dosimetry during CT-guided radiofrequency pulmonary tumor ablation

This study aimed to quantitatively evaluate regional absorbed doses at selected thoracic anatomical locations during computed tomography (CT)-guided radiofrequency (RF) pulmonary tumor ablation using an anthropomorphic phantom and thermoluminescent dosimeters (TLDs). An Alderson Rando anthropomorphic phantom representing an adult female was instrumented with TLD-100 (LiF:Mg,Ti) dosimeters placed at 18 anatomically defined internal and surface locations corresponding to critical thoracic organs. A CT-guided lung tumor ablation procedure was simulated using a multidetector CT system under clinically representative imaging parameters (120 kVp, 50 mA, helical mode). A total of 10 CT acquisitions were performed to mimic probe placement and verification steps. Absorbed doses were calculated using individually calibrated TLDs with traceability to national standards. The highest absorbed doses were measured in cardiac structures, with mean values of 15.34 ± 0.49 mGy for the left ventricle and 13.76 ± 0.36 mGy for the left atrium. Elevated doses were also observed in the mid-lung regions up to 13.37 ± 0.41 mGy. Lower dose levels were recorded in lung bases and apical regions approximately 4-7 mGy. Breast surface doses were low on anterior surfaces (≤2.87 mGy) but higher and more variable on posterior surfaces, reaching 9.83 ± 5.26 mGy. CT-guided pulmonary tumor ablation may result in clinically relevant radiation exposure to non-target thoracic organs, particularly cardiac structures. Phantom-based regional absorbed dose measurements provide valuable data to support dose optimization strategies in interventional thoracic imaging.