No abstract

Occupational radiation exposure is a hazard that should be avoided or at least minimised. This study aimed to evaluate the radiation exposure of nuclear medicine department employees monitored during the 1991-2007 period, and to investigate the relationship between the annual effective doses of the personnel and the number of radioisotope procedures performed. Overall, 2014 quarterly effective whole-body doses, categorised into six occupational groups, monitored with personal dosemeters, were analysed statistically. There was a wide variation in the average annual doses among the different occupational groups. During the 17 years covered by this study, there was no incidence of a dose exceeding the annual dose limit of 20 mSv. There was a weak correlation between the average annual dose for monitored employees and the number of nuclear medicine procedures performed. Apart from exposure, personal skill in dealing with radioactive substances, compliance with radiation protection rules is an important factor to minimise the effective dose.

The appropriate radiation protection measures applied in departments of nuclear medicine should lead to a reduction in doses received by the employees. During 1991-2007, at the Department of Nuclear Medicine of Pomeranian Medical University (Szczecin, Poland), nurses received on average two-times higher (4.6 mSv) annual doses to the whole body than those received by radiopharmacy technicians. The purpose of this work was to examine whether implementation of changes in the radiation protection protocol will considerably influence the reduction in whole-body doses received by the staff that are the most exposed. A reduction in nurses' exposure by ~63 % took place in 2008-11, whereas the exposure of radiopharmacy technicians grew by no more than 22 % in comparison with that in the period 1991-2007. Proper reorganisation of the work in departments of nuclear medicine can considerably affect dose reduction and bring about equal distribution of the exposure.

BACKGROUND:The prognostic value of myocardial perfusion scintigraphy (MPS) continues to attract interest and provoke discussions. This study was an attempt to investigate the methods.OBjeCtive: Determination of the prognostic value of MPS for patients suspected of and diagnosed with coronary artery disease (CAD). MAteRiAL AND MetHODS

This study was performed to find the optimal low-dose CT protocol for children being imaged on SPECT/CT scanners not equipped with automatic dose control. For SPECT/CT systems with manually adjustable x-ray tube voltage (kV) and anode current (mA), an optimized protocol makes it possible to minimize the dose to patients. Methods: Using the 4-slice low-dose CT component of a commercially available SPECT/ CT scanner, we compared the signals reaching the CT detector after radiation passes through objects of different sizes. First, the exit dose rates were measured for combinations of available voltages and currents. Next, imaging parameters were selected on the basis of acceptable levels of exit dose rates, cylindric phantoms of different diameters approximating children of different sizes were scanned using these parameters, and the quality of the CT images was evaluated. Finally, weighted CT dose indexes for abdomen and head CT dose phantoms simulating, respectively, adult and pediatric patients were measured using exactly the same techniques to estimate and compare doses to these 2 groups of patients. Results: For children with torsos smaller than 150 mm, imaging can be performed using the lowest available voltage and current (120 kV and 1 mA, respectively). For children with torsos less than 250 mm, 140 kV and 1.5 mA can be used. For patients with torsos greater than 250 and less than 300 mm, 140 kV and 2 mA can be used. Regarding the signal-to-noise ratio, all these parameters give an excellent signal and fully acceptable noise levels. Conclusion: For the SPECT/CT system studied, even the lowest available voltage and current used for scanning pediatric patients did not cause signal-to-noise degradation, and the use of these settings substantially lowered the dose to the patients. Di agnostic SPECT/CT systems allow CT scans to be registered with nuclear medicine scans so that radioisotope uptake can be localized. CT scans are additionally used for attenuation correction of radioisotope images. However, compared with SPECT-only examinations, SPECT/CT examinations increase the radiation exposure of patients. SPECT/CT systems with adjustable x-ray tube voltage (kV) and anode current (mA) make it possible to minimize the dose to patients. Reasonable reduction of CT-related dose in individual patients is an important issue, particularly in children (1,2). The aim of this study was to find the optimal pediatric CT protocol that reduces radiation risk. MATERIALS AND METHODSAll investigations used the 4-slice low-dose CT component of the Infinia Hawkeye 4 SPECT/CT system (GE Healthcare). In this system, both the voltage and the current are adjustable. To compare the signals reaching the CT detector after radiation passes through objects of different sizes, we measured the exit dose for all combinations of available voltages and currents. To simulate patients of different sizes, we used phantoms containing various volumes of water. During all measurements, the x-ray tube was immobilized at the 12-o'clock position in the...