Evaluation of radiation dose to patients undergoing interventional radiology procedures at Ramathibodi Hospital, Thailand.

Purpose: This study was carried out to assess the radiation dose to patients undergoing interventional radiology procedures at Ramathibodi Hospital, Bangkok, Thailand.

Methods: Data were collected from 60 patients under transarterial oily-chemoembolisation (TOCE) and femoral angiography performed with the Toshiba Infinix model VC-i FPD single plane system. Data were also collected from 60 patients who underwent brain arteriovenous malformations (AVM) and dural-arteriovenous fistula (DAVF) embolisation, performed with the Toshiba Infinix model VF-i bi-plane systems. A built-in air kerma area product (KAP) meter calibrated in situ was used for the skin dose calculation.

Results: The calibration coefficient of air kerma area product meter at tube voltage between 50 kV and 100 kV was found to vary within ± 5.07%, ± 7.2%, ± 4.86 % from calibration coefficient of 80 kV for a single-plane, tube 1 and tube 2 of bi-plane x-ray system, respectively. Mean air kerma area product values were 90.99 ± 52.89, 31.02 ± 17.92, 33.11 ± 23.99 (Frontal), 35.01 ± 19.10 (Lateral), 50.15 ± 44.76 (Frontal), 97.31 ± 44.12 (Lateral) Gy-cm(2) for transarterial oily-chemoembolisation, femoral angiography, diagnostic cerebral angiography, therapeutic cerebral angiography, respectively. The therapeutic cerebral angiography procedure was found to give the highest entrance dose, number of images and fluoroscopy time: 362.63 cGy (Lateral), 1015 images (Lateral) and 126 minutes, respectively. However, the highest air kerma area product value was from transarterial oily-chemoembolisation with 264.37 Gy-cm(2). There were 2 cases of therapeutic cerebral angiography, where the patient entrance dose was higher than 3 Gy in the frontal view, which reached the deterministic threshold for temporary epilation.

Conclusion: Very wide variationswere found in patient dose from different interventional procedures. There is a need for a dose record system to provide feedback to radiologists who perform the procedures; especially in cases where the dose exceeds the deterministic threshold.