Medical workers operating in nuclear medicine vs PET/CT: Radiation exposure comparison

Abstract

s / Physica Medica 30 (2014) e16ee44 e31 Background: Long-lived radioactive impurities in radiopharmaceuticals administered at time of calibration usually have minor impact on image quality and the uncertainty of the activity measurement. However, such impurities may result to non-negligible additional radiation burden to patients, personnel, relatives, caregivers and the public, and may trigger innocent alarms in radiation portal monitors. In addition, the presence of certain levels of impurities may impose modifications in waste management policies. The aim of the present study was to identify the most important long-lived impurities, quantify their amount in the patients’ body and address radiation protection issues. Methods and materials: Initial analysis of the radiopharmaceuticals used at the Ioannina University Hospital indicated substantial amounts of longlived (T1/2> 14 d) photon emitting impurities only in 123I-ioflupene (DaTSCAN, GE) and 153Sm-EDMTP (Quadramet, IBA). Spectroscopic analysis of the residuals of at least ten administrations per agent was carried out at least five times per sample. A prototype shadow-shield whole body counter equipped with 16 NaI(Tl) detectors was used to measure the activity present in at least 7 seven patients per agent, 2 to 5 five weeks postadministration. The in vivo activity measurements were coupled with external dose rate measurements using a portable system with spectroscopic capabilities. Results: 121Te, 123Te and 125I were the main photon emitting impurities in 123I-ioflupene, resulting in a median 30 nSv/h external Hp(10) rate and a 3 kBq 121Te body burden. 152Eu, 152Eu and 156Eu were the main impurities in 153Sm-EDMTP, resulting in amedian 300 nSv/h external rate, mainly due to the 152Eu (T1/2:13.5 y) and 154Eu (T1/2:8.6 y) presence in the body, 25 and 33 kBq, respectively. Thus patient and waste management protocols were modified accordingly. Conclusions: Both patient and waste management have to take into account the long-lived impurities present in some of the agents used in daily clinical practice. MEDICAL WORKERS OPERATING IN NUCLEAR MEDICINE VS PET/CT: RADIATION EXPOSURE COMPARISON K. Dalianis , J. Malamitsi , K. Gogos , R. Efthimiadou , J. Andreou , V. Prassopoulos . a PET/CT Department Hygeia SA, Athens, Greece; Medical Physics Laboratory School of Medicine, University of Athens, Greece Purpose: Personnel monitoring results provide information on routine radiation exposure, assist in work planning and allow control of the workplace. The aim of this study was to compare the gamma dose received by dedicated medical workers operating in the first PET/CT department in Greece and also by dedicated medical workers operating in conventional Nuclear Medicine procedures in the same center. PET/CT studies are restricted to the use of 18F fluorodeoxyglucose (FDG). In addition Tc-99m, Tl-201, Ga-67 and I-131 are the radiotracers mostly used in our Nuclear Medicine department. Method: To estimate the effective dose from external exposure, all 9 members of the staff (2 nurses, 2 medical physicists, 5 technologists) had TLD badges worn at the upper pocket of their overall and digital dosimeters worn at the side pocket. Nurses and Medical Physicists also had TLD rings. The nurses and technologists 1,2 are working only in the PET/CT department, while technologists 3,4,5 are operating only in the Nuclear Medicine department covering the most common procedures. Medical Physicists 1,2 are operating in both departments. Results: In the period of January 2013 to December 2013 a total of 982 PET/ CT studies and 2157 conventional Nuclear Medicine procedures were performed. The collective effective and finger doses received by all 4 members of the PET/CT staff were the following: Nurse 1 received 2,94 mSv as a whole body dose and 6,84 mSv as a hand dose and Nurse 2 received 2,87 mSv whole body dose and 5,91 mSv hand dose respectively. Technologists 1 and 2 received 1,95 mSv and 1,56 mSv as the whole body dose respectively. Medical Physicist 1 received 1,75 mSv whole body dose and 7,77 mSv hand dose and Medical Physicist received 2 2,17 mSv and 4,68 mSv respectively. Technologists 3,4 and 5 received 1,85 mSv, 1,76 mSv and 1,82 mSv as whole body doses respectively Conclusion: The personnel dose results are significantly lower than the recommended annual dose by International Commission for Radiological Protection. The higher value of gamma dose for PET/CT workers by comparison with the staff operating conventional Nuclear Medicine procedures is attributable to the higher specific gamma constant of 18F, as well as the longer exposure time required for accurate positioning. THREE-DIMENSIONAL METRICS FOR QUANTITATIVE MONITORING OF TREATMENT EFFECTS WITH PET/CT N. Politis , A. Georgakopoulos , M. Metaxas , S. Chatziioannou , M. Kallergi . Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece; Nuclear Medicine Division, Biomedical Research Foundation of the Academy of Athens, Greece; Nuclear Medicine Section, 2 Department of Radiology, “Attikon” University General Hospital, National and Kapodistrian University of