UPTAKE AND DISTRIBUTION OF RADIOSTRONTIUM IN TOMATO TREATED WITH ARBUSCULAR MYCORRHIZAL FUNGI.

Arbuscular mycorrhizal fungi (AMF) were inoculated into the root system of edible tomato plants to investigate their effect on the uptake and distribution of strontium radionuclide in the tissues of plants grown under laboratory conditions. The experiments were carried out in a sterile mixture of topsoil and sand, where in one series of experiments contaminated soil with 85Sr was used. Seeds were inoculated with a mixture of AMF at sowing, the second, control series was without application of AMF. Determination of radioactivity in soil and in different parts of tomato plants was carried out by gamma-spectrometric measurement. The obtained results and statistical analysis indicated a significant association between AMF inoculation of plants and the change in the distribution of 85Sr. The presence of AMF reduced the translocation of 85Sr from the root system to the aerial parts of tomato plants.

PRECAUTION IN THE USE OF EFFECTIVE DOSE IN CORONARY CT ANGIOGRAPHY.

The effective dose is a quantity used in clinical practice for statistical evaluation of the radiation dose of patients undergoing different types of examinations. Coronary computed tomography angiography (CCTA) is a specific examination whose calculated effective dose may be subject to several biases. For this reason, it is important to consider factors (different examination techniques, heart rate and patient habitus) that may influence its resulting value. Another critical factor is the methodological procedure for calculating the effective dose and cardiac-specific coefficient used to estimate effective dose from the dose-length product in computed tomography. Because CCTA is increasingly used in cardiology, it is recommended that the chest coefficient be replaced with a new cardiac coefficient when calculating the effective dose.

THE IMPORTANCE OF FEEDBACK IN MONITORING PATIENTS' RADIATION DOSES IN MAMMOGRAPHY.

The majority of medical facilities in the Slovak Republic archive diagnostic images of their patients in a picture archiving and communicating system (PACS). Data from the PACS system can be used to analyse patient radiation dose and perform internal and external quality control through dose monitoring software systems. However, appropriate use of such systems requires the provision of feedback and the ability of staff to identify causes of diagnostic reference level exceedances. The present pilot study evaluated the use of a Dose quality control system (DQC) for monitoring the radiation dose of the patients in the ongoing mammography screening, with subsequent identification of alerts triggered by the system.

Comparison of pencil-type ionization chamber calibration results and methods between dosimetry laboratories.

A comparison of calibration results and procedures in terms of air kerma length product, PKL, and air kerma, K, was conducted between eight dosimetry laboratories. A pencil-type ionization chamber (IC), generally used for computed tomography dose measurements, was calibrated according to three calibration methods, while its residual signal and other characteristics (sensitivity profile, active length) were assessed. The results showed that the "partial irradiation method" is the preferred method for the pencil-type IC calibration in terms of PKL and it could be applied by the calibration laboratories successfully. Most of the participating laboratories achieved high level of agreement (>99%) for both dosimetry quantities (PKL and K). Estimated relative standard uncertainties of comparison results vary among laboratories from 0.34% to 2.32% depending on the quantity, beam quality and calibration method applied. Detailed analysis of the assigned uncertainties have been presented and discussed.