In nuclear medicine, patients are injected with radiopharmaceuticals for diagnostic or radiotherapeutic procedures. In order to ensure adequate radiation protection of the medical staff and the public, it is necessary to consider the impact of the radiation emitted by the patient, for example, when he/she is guided in the hospital or he/she will leave the hospital after the procedure. Such exposures may occur unknowingly to members of the public or knowingly to people who comfort the patients after the procedure, such as relatives and friends.
Currently there are a limited number of studies on the assessment of potential external dose to comforters, carers and family. Most studies were performed for diagnostic procedures, where the patient is injected with Tc-99m or F-18. In case of therapeutic procedures, data can be found for I-131 therapy to treat thyroid cancer or hyperthyroidism. Although for diagnostic studies, in general, the studies indicate no need of any restrictions before a patient can be released from the hospital, the issue is still in debate. For example, the EMA (European Medicines Agency) recommends to avoid close contact with children or pregnant women for 24h after injection in case of Tc-99m procedures.
If guidelines exist, they are mainly related to I-131 therapy. In any case, all information available on the protection of carers and comforters of nuclear medicine patients, both for diagnostic and therapeutic procedures, is based on dose rate measurements in a single point at a certain distance from the patient and measured on several time points after injection. To assess the exposure level and possible risk to comforters, these dose rate measurements are combined with assumed specific occupancy scenario’s, describing how long carers/comforters are in close contact with a nuclear medicine patient over time. Because a nuclear medicine patient is a physically large radiation source, reducing that source to a dose rate in a single point is prone to large errors, especially at short distances from that patient.
However, the growing number of patients treated and the diversity of radiopharmaceuticals used to diagnose, treat and follow-up patients, stimulates to evaluate risks related to comforters of nuclear medicine patients. In this study, the external dose rates to comforters, carers and other persons, will be evaluated through a more advanced and detailed computational approach.