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OBJECTIVES: The initial management of a trauma patient often involves imaging in the form of x-rays, computed tomography (CT) and other radiographic studies, which expose the patient to ionizing radiation, an entity known to cause tissue injury and malignancy at high doses. The purpose of this study was to use a calculation-based method to determine the radiation exposure of trauma patients undergoing trauma team activation in a Canadian tertiary-care trauma centre. METHODS: A retrospective chart review was conducted using the Nova Scotia Provincial Trauma Registry. All patients age 16 years old and over who underwent trauma team activation between March 1, 2008 and March 1, 2009 were included. Patients who died prior to imaging tests were excluded. Dose reports for each CT were used to calculate a whole-body radiation dose for each patient. RESULTS: There were 230 trauma team activations during the study period, of which 206 had CT imaging. Data were available for 162 patients. The mean whole-body radiation exposure for all patients was 24.4±10.3 mSv, which may correlate to one additional cancer death for every 100 trauma patients scanned. CONCLUSIONS: Trauma patients are exposed to significant amounts of radiation during their initial trauma work-up, which may increase the risk of fatal cancer. Clinicians who care for these patients must be aware of the radiation exposure, and take measures to limit radiation exposure of trauma patients.

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PURPOSE: To establish local diagnostic reference levels (DRL) for typical radiographic examinations in a fully digital imaging institution. METHODS: The initial survey included 6 standard radiographic projections performed in 19 computed radiography (CR) and digital radiography (DR) rooms. Because of the expected difference in the performance, the local reference levels were analysed separately for those 2 modalities. Data of 226 average size adult patients were included in the analysis. Entrance surface dose (ESD) was calculated from the recorded radiographic techniques and tube radiation output measurements. After observing wide variations in the results of the patient survey, the examinations were repeated by using anthropomorphic phantoms. Initial efforts to understand the reasons for dose variations were focused on CR chest, abdomen, pelvis, and lumbar spine examinations. RESULTS: The average size patient doses for similar examinations were lower in the DR rooms than in the CR rooms by factors that ranged from 1.2 to 3, with the exception of the chest examination. Standardization of the CR exposure index value allowed us to decrease ESD by 21%-30%. Detector sensitivity had an insignificant effect (2%) on ESD; proper collimation lowered the dose by 17%. However, the major effect, up to 46% difference, was found because of antiscatter grids cutoff. CONCLUSION: Modality specific local diagnostic reference levels for standard examinations have been established in a large digital imaging department with hybrid modalities. Typically the local reference values were lower than those recommended in Safety Code 35, except for CR chests. Factors that affect the dose variations have been investigated and determined.

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OBJECTIVE: To determine the effectiveness of surface radiation shields of gonads outside the primary x-ray beam. METHODS: Radiographic and computed tomography air kerma measurements were made on a standard anthropomorphic phantom to quantify the amount of external and internal scatter radiation to the gonads of males and females. These amounts were calculated from air kerma measurements using three different methods: with no shielding, with surface lead shields, and with axial lead shields located between the gonads and the primary x-ray beam. Measurements were made with the distance of the primary radiation field to the dosimeter ranging from 0 to 20 cm and at kVp values ranging from 60 to 120. RESULTS: The contribution of external radiation to the total amount of gonadal radiation during radiographic procedures was 15 ± 13.1% for males and 5 ± 5.6% for females, respectively. For computed tomography, external radiation contributed 9 ± 6.8% and 4.3 ± 8.1% to the total gonadal radiation for males and females, respectively. CONCLUSION: For body parts outside the primary radiation beam, the main source of radiation is from internal scatter. Because surface radiation shields can only protect against external radiation, their value as radiation protection devices is limited.