hrvatski

Procjene osobnih doza u nekim tipičnim nuklearno medicinskim postupcima

In a frame of continuous quality improvement program in the Department of Oncology and Nuclear Medicine, KB "Sestre milosrdnice", we assessed personal radiation doses from external exposures related to some typical daily nuclear medicine procedures. This study primarily aimed at: establishing more balanced distribution of daily work in the department, recognizing needs for improved radiation protection measures and personal protective equipment, providing data for analysis of dose distributions and for evaluation of trends, observing individual work and needs for training and retraining. Responses of the dosimeters were measured with a small 99m-Tc source produced in-house, and 137-Ce and 226-Ra sources with calibration certificate. The dose and the dose rate measurements were performed with 137-Cs and 226-Ra sources for several distances and times of measurement. Similarly, just the dose measurements were made for 99m-Tc source. Personal dose measurements were done daily by a single dosimeter worn on the lead apron at the upper part of the chest. For the purpose of the study, workers were distributed into groups according to the type of work performed, activities handled and criteria accepted from previous organization scheme. Results: The dosimeters show good agreement of the measured and calculated dose for 99m-Tc source. However, for 226-Ra and 137-Cs sources, measured doses were underestimated. Anisotropy of dose rate response assessed for four positions with 226-Ra and 137-Cs is large. For routine use in the department, the response of the dosimeters to various energies should be thoroughly investigated. Despite some technical shortcomings which inhibit reliable work and urge for improvements, they could be a supplemental tool in personal dosimetry mainly because their direct display encourages person to be more cautious when doing repeated and sometimes boring daily operations. The majority of work in department can be done safely and with acceptable personal effective doses below one tenth of the recommended annual effective dose constraint. Results for the most exposed group indicate that more efforts should be made in order to reach department's ALARA goal to have an effective dose for each worker below one fifth of the recommended dose constraint.

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