Radiation dose to nuclear medicine technologists when operating PET/MR compared with PET/CT.

Since 2010, positron emission tomography/magnetic resonance (PET/MR) has been increasingly used as clinical routine in nuclear medicine departments. One advantage of PET/MR over PET/computed tomography (CT) is the lower dose of ionising radiation delivered to patients. However, data on the radiation dose delivered to staff operating PET/MR compared with the new generation of PET/CT equipment are still lacking. Our aim was to compare the radiation dose to nuclear medicine technologists performing routine PET/MR and PET/CT in the same department. We retrospectively measured the daily radiation dose received by PET technologists over 13 months by collecting individual dosimetry measurements (from electronic personal dosimeters). Data were analysed taking into account the total number of studies performed with each PET modality (PET/MR with Signa 3T, General Electric Healthcare versus PET/CT with Biograph mCT flow, Siemens), the type of exploration (brain versus whole-body PET), the18F activity injected per day and per patient as well as the time spent in contact with patients after tracer injection. Our results show a significantly higher whole-body exposure to technologists for PET/MR compared with PET/CT (10.3 ± 3.5 nSv versus 4.7 ± 1.2 nSv per18F injected MBq, respectively;p< 0.05). This difference was related to prolonged contact with injected patients during patient positioning with the PET/MR device and MR coil placement, especially in whole-body studies. For an equal injected activity, radiation exposure to PET technologists for PET/MR was twice that of PET/CT. To minimise the radiation dose to staff, efforts should be made to optimise patient positioning, even in departments with extensive PET/CT experience.

Measurement of Occupational Eye and Thyroid Radiation Doses in Pediatric Interventional Cardiologists at a Tertiary Hospital.

Background Advances in imaging techniques have led to increased utilization of imaging devices in catheterization laboratories. Invasive surgical procedures for cardiac disorders have been largely replaced by fluoroscopic cardiac catheterization. With this increase, concerns and risks associated with exposure to ionizing radiation among interventional cardiologists are growing. This study aims to measure and compare the occupational doses to the eye lens and thyroid of pediatric interventional cardiologists during different procedures in the catheterization laboratory and its significance. Methodology In this study, cardiologists wore bandanas with attached dosimeters to measure the absorbed doses to the eyes and thyroid gland. The dosimeters were collected for reading. The procedure types were also collected. In addition, the total fluoroscopy time and tube voltage of the biplane machine were measured. SPSS version 23 (IBM Corp., Armonk, NY, USA) was used to analyze the data. The characteristics of the study sample were described using simple counts and percentages, whereas means and standard deviations were used for continuous variables. Statistical significance was set at p-values <0.05. Results A total of 93 procedures were evaluated. The mean absorbed doses for all 93 procedures in both eyes and thyroid were 0.09 mGy and 0.08 mGy, respectively. A significant difference was found between the left and right eye measurements (p = 0.034), with higher doses administered to the left eye. However, no significant difference was observed between the right and left thyroid doses (p = 0.281). Significant correlations were found between the eye and thyroid doses and the procedure type (p = 0.02 and p = 0.009, respectively). Conclusions A significant amount of radiation was measured in the measurements of both organs. In addition, radiation dose measurements varied between different types of procedures. Our current results indicate the importance and necessity of applying the radiation protection concept of dose optimization.

Referral to radioisotope examination as a source of additional radiation exposure for staff.

BACKGROUND: Every exposure of human to ionizing radiation increases the likelihood of deterministic sequelae. At the same time, it is associated with the risk of stochastic effects. Consequently, this can lead to cancer, mainly of the hematopoietic system. Organs or tissues show a different affinity for gamma radiation. There are many technical and organizational measures which minimize the impact of this radiation on people and especially on the staff of the nuclear medicine laboratory. MATERIALS AND METHODS: The study was based on 208 referrals to the scintigraphic laboratory, which were executed between 26.09.2018 and 13.11.2018 in the Department of Nuclear Medicine of Military Medical Academy Memorial Teaching Hospital of the Medical University of Lodz - Central Veterans` Hospital. Referrals concerned scintigraphic tests of bones, salivary glands, parathyroid glands, myocardial perfusion, somatostatin receptor analogues, renoscintigraphic and lymphoscintigraphic tests. In case of each referral, radiation power was measured at a distance of approx. 10 cm with the use of a calibrated Geiger-Muller detector. Measurements were performed immediately after the end of the last examination each day. Daily measurement of the background radiation dose was also a standard procedure. For calculations, this value was averaged to 0.18µSv/h. Based on the above measurements, a statistical analysis of all data was performed. Obtained data was also analysed after it was ascribed to the person complexing radiopharmaceuticals on a given day. The annual dose for a radiopharmacist is 0.12 mSv, for a technician 0.35 mSv and for a doctor 0.45 mSv. RESULTS: The average radiation dose received every working day by the staff was 11.49 µSv/h. After considering the average distance from the potential source of exposure (50 cm), this power decreased to 0.46µSv/h. In order to calculate the quarterly and annual radiation dose, it was assumed that the employee worked 250 days a year. CONCLUSIONS: Medical records may pose an additional personnel exposure to ionizing radiation. Physicians are the most vulnerable group of employees. The way of radiopharmacists work contributes to the contamination of medical records.