engleski

Staff doses during coronarography procedure

The number of diagnostic and therapeutic procedures in cardiology that require the use of ionizing radiation is increasing constantly. A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter, while it is one of the highest potential exposures of the staff. The new IAEA Basic Safety Standard (Interim Edition, 2011) recommends limit of 100 mSv/5 years for the whole body and 20 mSv equivalent dose for eyes for professionals. To satisfy these requirements, the staff doses in cardiology were investigated in the Haemodynamic Laboratory of a Cardiology Department, Budapest. The aim of this work was the determination of staff exposure during coronarography diagnostics and the investigation of the effect of some factors (working method, fluoroscopy time, body) on the dose to personnel. The measured doses were compared to the doses measured by the National Dosimetry Service. The doses were measured under and over the apron on the chest, on the left eye (eyebrow), left shoulder out of the apron, and left wrist of 3 cardiology doctors. Each doctor carried out 5 diagnostic coronarography procedures. The doctors were wearing 0.5 mm thick lead aprons (one doctor had it 1mm thick) and thyroid collar. Additional 0.5 mm thick lead glass protection hanging from the ceiling and protection between the table and the floor were applied. For the protection of patients 0.5 mm Pb sheet was used. No protective glasses were used for the eyes. The doses were measured with thermoluminescence - TL (LiF:Mg, Cu, P-MCPN) and radiophotoluminescence - RPL (GD-352M) dosimetry systems. No systematic difference between the TL and RPL dosimetry systems was found. The annual effective doses Eeff, calculated from the measured values as well as the equivalent doses to the eyes, were in all cases below the dose limit (20 mSv/year). Significant differences of the effective doses were found among the three doctors in a recent study (15.5 mSv, 10.4 mSv, 8, 7 mSv), as well as in the earlier results of the National Dosimetry Service (9.2 mSv, 4.6 mSv, 1.3 mSv), i.e. one doctor with a long experience received higher doses than the other two. From these results it can be also seen that a single dosimeter under the apron performed by the National Service underestimates the Eeff as compared to the double dosimetry carried out in this study. The doses depend on many factors in coronarography, such as fluoroscopy time, complexity and number of examinations, experience of the doctor, feature of the doctor (height) and patient himself. Therefore measurements with good statistics have to be carried out.

Staff doses; interventional radiology; coronarography procedure; TLD; RPL

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