Radiation doses to patients undergoing barium meal and barium enema examinations.

The radiation doses received by patients during 41 barium meal (BM) and 42 barium enema (BE) examinations in two Greek hospitals are presented. Radiation dose was measured in terms of the dose area product (DAP). The effective dose and doses to certain organs were estimated using the ODS-60 software. Mean total DAP values were found to be 25 +/- 11 Gy cm2 for BM and 60 +/- 35 Gy cm2 for BE examinations, whereas the estimated mean values of effective dose were 8.6 +/- 4.0 and 24 +/- 16 mSv respectively. DAP to effective dose conversion coefficients were estimated to be 0.34 mSv per Gy cm2 for BM and 0.41 mSv per Gy cm2 for BE.

Radiation doses to paediatric patients up to 5 years of age undergoing micturating cystourethrography examinations and its dependence on patient age: a Monte Carlo study.

The effective dose received by children up to 5 years of age from micturating cystourethrography (MCU) examinations was estimated in this study. The MCU examination consisted of 5 radiological views, 2 anteroposterior (AP) and three oblique (OBL) views. Entrance surface doses (ESD) were measured with thermoluminescent dosimeters for 30 children. The average ESD values per view varied from 0.34 mGy up to 0.57 mGy. In order to calculate the organ and effective doses, Monte Carlo MCNP-4A radiation transport simulation code was used. It was applied to three mathematical phantoms representing newborn, 1 and 5 year old children and all the patients were classified in those three groups. The effective dose conversion factors (C(f)) were calculated as the ratio of effective dose over the entrance dose. The C(f) factors decrease as the children's age increases. Children simulated by a newborn mathematical phantom, had C(f) factors almost double those represented by a 1-year-old mathematical phantom. For children simulated by a 5 year old phantom, the C(f) factors for AP and OBL views were almost the same. This was true for both male and female patients. The mean effective dose per view for male and female patients was found to be E=0.16 mSv. The effective dose per examination for male patients was E=0.86+/-0.31 mSv and E=0.76+/-0.28 mSv for female patients.

Radiation doses to patients undergoing coronary angiography and percutaneous transluminal coronary angioplasty.

A detailed study of radiation doses received by 168 patients who underwent coronary angiography (CAG) and 102 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) in two Greek hospitals is presented. Radiation dose was measured in terms of dose-area product (DAP). The contribution of fluoroscopy and cineradiography to the total DAP was examined separately for each radiological projection used in both procedures. Effective dose and doses to various organs were estimated with the help of the ODS-60 software. Total DAP was found to correlate linearly to fluoroscopy time and cine film length. Mean DAP values were found to be 80.8 +/- 28.0 Gy cm2 for CAG and 86.2 +/- 65.6 Gy cm2 for PTCAs, whereas the estimated mean values of effective dose were 20.9 +/- 7.5 and 23.2 +/- 18.1 mSv respectively. DAP to effective dose conversion coefficients were estimated to be 0.26 mSv/Gy cm2 for CAG and 0.27 mSv/Gy cm2 for PTCAs.

Dosimetric considerations in mammography.

The aim of this study was to measure the absorbed dose to seven organs other than the breast in mammography in order to calculate their contribution to the effective dose. The absorbed dose to these organs was measured using a lucite upper body anthropomorphic phantom containing thermoluminescent dosimeters (TLD) at appropriate locations, exposed as in a mammographic examination. In addition, the dependence of the absorbed dose on kVp, mAs and breast thickness was examined. The absorbed dose due to scattered radiation was found to be negligible to all organs except to the sternum red bone marrow (SRBM) and the thyroid. The mean doses to the SRBM and the thyroid, for a set of four exposures, one craniocaudal and one 90 degrees mediolateral per breast, simulating a complete breast screening examination, varied between 0.40 and 1.27 and 0.05-0.17 microGy mAs(-1), respectively, depending on the breast thickness and the kVp selection. Effective dose from mammography was also calculated based on the absorbed dose to the breast, the SRBM and the thyroid and tissue-weighting factors. The effective dose was found to vary between 0.66 and 0.85 microSv mAs(-1) depending on the breast thickness and the kVp value selected. The radiation dose to the breast contributes over 98% to the effective dose.