Evaluation of the radiation exposure of interventional personnel during CT-guided percutaneous cryoablation (CryoDos)

• Applicant: Professor Dr. Thomas J. Vogl
• Subject Area: Radiology ; Medical Physics, Biomedical Technology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550591192

In recent decades, a large number of technical innovations and optimizations have been made in interventional procedures to reduce the dose for patients and interventional staff. Nevertheless, regular exposure to radiation during CT-based interventions is still a major problem, especially in complex procedures where radiologists and assistants have to be close to the patient. Given the increased risk of medical staff developing cancer or even deterministic skin damage, effective strategies for monitoring and reducing the radiation dose are required. With the European Directive 2013/59/Euratom laying down basic safety standards for protection against the dangers arising from ionizing radiation, EU Member States are committed to establishing legal requirements and an adequate system of regulatory control based on the principles of justification, optimization and dose limitation for all exposure situations. However, the number of studies on the optimization of radiation protection in CT fluoroscopy is still very limited. In addition to conventional puncture procedures, therapeutic procedures such as microwave ablation and cryoablation have also increased rapidly in recent decades. The joint guideline of the Cardiovascular and Interventional Radiology Society of Europe (CIRSE) and the Society of Interventional Radiology (SIR) as well as the International Commission on Radiological Protection (ICRP) also express concerns about the high radiation doses for interventional personnel. The aim of this research project is to evaluate the radiation dose during CT-guided percutaneous cryoablation in three-dimensional space in order to estimate the radiation exposure for the entire interventional team. Compared to other minimally invasive percutaneous ablation procedures, such as microwave ablation, the time required for cryoablation is considerable due to multiple freeze-thaw cycles. The positioning of the applicator in the target tissue and the ablation are monitored and controlled by image guidance. Furthermore, the relatively large cryoapplicator is made of stainless steel, so that its influence in the CT radiation field on the scattered radiation is to be investigated in more detail. Considerable dose values for the hand and its surroundings are expected, particularly when the applicator head is held in place by the radiologist during therapy and when the needle is positioned in the target tissue. In order to estimate the dose during cryotherapy for the entire intervention team and the corresponding body parts, the three-dimensional dose distribution in the CT room is determined and analyzed in different angular positions of the cryoapplicator. System-side methods for dose reduction, such as angular beam modulation, are investigated and evaluated with regard to optimization and dose limitation for any exposure situation.

• DFG Programme: Research Grants