Abstract:
To evaluate the radiation dose to patient at two positions (prone and left lateral) and to medical staff during ERCP procedure using dose area product (DAP) meter and thermoluminescent dosimeter (TLD). Data were recorded on 20 patients at prone position and 20 patients at left lateral position. The radiographic-fluoroscopic system manufactured by Siemens Model Polystar was used for ERCP procedure at King Chulalongkorn Memorial Hospital. Dose Area Product (DAP) manufactured by PTW Model Diamentor E, a transmission ionization chamber was attached to X-ray collimator to record the dose-area (cGy.sq.cm) in order to determine the entrance surface air kerma (ESAK, mGy) of the patients at two positions (prone and left lateral) while the Kodak Portal Pack for localization imaging was placed on the patient's couch to determine the exposed area (sq.cm) on the surface of the patient. TLD was attached at five positions, left eye, thyroid, left forearm, lower abdomen and left leg of the medical staff during ERCP procedure. The average patient skin dose from DAP was higher at left lateral position of 124.06 (23.3-229.3) mGy than 82.93 (39.76-174.74) mGy at prone position. The medical staff received the maximum dose per procedure at the left forearm of 244.02 (54.79-1628.66) μGy for patient at left lateral position and 131.09 (29.9-382.81) μGy at prone position. The average surface dose the patient received during ERCP procedure at prone and lateral positions were 82.93 and 124.06 mGy per procedure which were significantly different. The medical staff also received higher dose at left lateral position than at prone position, but they were adequately protected from the risk of working with the radiation. The relation between medical staff and patient doses was established. The highest ratio between average medical staff doses and dose-area product is the left forearm and the lowest ratio is the lower abdomen of ERCP procedure. The highest ratio is 111.66 μGy / 10 Gy.sq.cm and the lowest ratio is 7.53 μGy / 10 Gy.sq.cm. The medical staff dose can be estimated from the patient dose using DAP method. This will help the medical staff to avoid the excess dose during their work.
