| Abstract [eng] |
Worker monitoring is a necessity for any radiation protection program. The personnel in Nuclear medicine (NM) department receives low whole-body doses which is easily monitored with passive individual dosimeters positioned on the chest. However, these workers come in close contact with radionuclides during labelling, dispensing or injecting of the radiopharmaceuticals to the patients, thus they may get higher doses to the hands. The biggest challenge in extremities monitoring is to foresee which part of the hand is the most exposed. Usually, for assessment of the hand doses, TLD ring dosimeter is used. The recommendations on how and where to wear ring a dosimeter depends on national regulations. Moreover, different correction factors are used for assessment of fingertip doses. The extremities monitoring is extremely relevant issue for investigation, due to the increasing number of nuclear medicine procedures and request for ensuring radiation safety, as well as updating working protocols for protection of the health of the worker. The aim of this thesis was to evaluate personal dose equivalent, Hp(10) to NM staff and dose equivalent to their extremities, Hp(0.07) during manipulation of 99mTc labelled radiopharmaceuticals and to assess relationship between these two values. This investigation was conducted in the Nuclear Medicine Department of the Hospital of Lithuanian University of Health Sciences (LSMU) Kauno Klinikos. The doses of the extremities were collected and evaluated for four technologists working in this department. Moreover, measurements were performed using a prosthetic hand, to simulate the actions of the technologist during preparation of the 99mTc labelled radiopharmaceuticals, measurements were done using TLDs. Also, whole body doses were considered. It was found that the whole-body exposure is less when working in a 99mTc preparation laboratory, than in radiopharmaceuticals injection rooms. Moreover, the results have shown that the technologist with the shortest working experience collected higher (14.36 μSv) accumulated doses in comparison with his colleagues. Based on the estimated highest doses to the fingertips, recommendations were prepared, regarding place, where to wear a ring dosimeter. For 4th and 1st technologists, the recommendation was to wear ring dosimeter on a middle finger of the right hand (maximum doses – 6.37 mSv and 1.27 mSv, respectively). Performed experiment with artificial hand phantom indicated an index finger as the most exposed one; the difference between, maximum dose of the finger and dose obtained at the ring place is 15 times. This leads to the suggestion that hand exposure measurement should be performed in order to give advice, regarding the ring finger dosimeter placement. |
