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

Abstract

Purpose: Since 2010, PET/MR has been increasingly used for clinical routine in nuclear medicine departments. One advantage of PET/MR over PET/CT is the lower ionising radiation dose delivered to patients. However, data on the radiation dose delivered to staff operating PET/MR compared to new generation PET/CT is 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. Methods: We retrospectively measured during 13 months, the daily radiation dose received by PET technologists by collecting individual dosimetry measurements (from electronic personal dosimeters). Data were analysed taking into account the total number of studies performed of each PET modality (PET/MR with Signa 3T, General Electric Healthcare vs. PET/CT with Biograph mCT flow, Siemens), the type of exploration (brain vs. whole body PET), the 18F activity injected per day and per patient as well as the time spent in contact with patients after tracer injection. Results: Our results show a significantly higher technologist staff whole-body exposure for PET/MR compared to PET/CT of 10.3±3.5 nSv versus 4.7±1.2 nSv per 18F injected MBq, respectively (p<0.05). This difference was related to prolonged contact with injected patients during patient positioning with PET/MR device and MR coils placement, especially in whole-body studies. Conclusions: For an equal injected activity, PET technologist radiation exposure for PET/MR was two-fold that of PET/CT. To minimize radiation dose to staff, efforts should be made to optimize patient positioning, even in departments with extensive PET/CT experience.

Thermoluminescence dosimetry (TLD) in a 3 T magnetic resonance imaging (MRI) environment: implications for personnel exposure monitoring

“…Existing studies on this subject exhibit variations in TLD material, radiation type or energy, strength of magnetic field, and dose levels. Additionally, certain studies either omit information on the TLD material used or employ doses at the scale of radiation therapy, exceeding typical occupational doses for healthcare professionals [9][10][11][12][13].…”

“…Soret M et al reported that, for an equal injected activity to patient, the radiation dose to technologists working with PET/MR was double that of PET/CT. The difference was associated with extended contact with injected patients during patient positioning with the PET/ MR and MR coil placement, especially in whole-body studies [11]. However, electronic dosimeters were used in that study and the possible effect of the magnetic field of MRI on dosimeters was not included in the study.…”

Radiation Exposure Characteristics among Healthcare Workers: Before and After Japan's Ordinance Revision

“…Data on monthly radiation exposure doses were collected by using personal dosimeters (Chiyoda Technol, Japan) during the respective time periods. Doses were measured in sieverts (Sv) as dose equivalent Hp(10), which represents the dose equivalent in soft tissue at a depth of 10 mm (Soret et al 2022). The limit of the detection (LOD) is 0.05 mSv, and the dosimeter was exchanged on a monthly cycle.…”