A proposed simple model for estimating occupational radiation dose to staff from veterinary 18F-FDG pet procedures

Several studies have been conducted concerning the radiation dose to hospital personnel from positron emission tomography (PET) radiopharmaceuticals, but to date only one parallel study has been conducted for veterinary staff. Veterinary patients present challenges not encountered with human patients, as they require anesthesia and therefore more intensive monitoring than human patients. This paper presents a simple model for estimating the effective radiation dose to veterinary staff using occupational dose data from PET studies at Colorado State University's (CSU) James L. Voss Veterinary Teaching Hospital. The model consists of three point sources within a soft tissue cylinder, and sample calculations are provided for estimating dose to nuclear medicine technologists and an anesthesia technologist based on four different sized dogs. The estimated doses are within the range of actual occupational doses published previously. There are different protocols for the sequence of events in veterinary PET, specifically the order of anesthesia induction and radiopharmaceutical injection. When F-FDG injection is performed prior to anesthesia induction, the estimated dose is between 1.5 and 3.6 times higher than the doses received if injection is done after anesthesia induction, although expected doses for both protocols are below occupational dose limits based on a case load of 100 veterinary patients per year. The model is based on the techniques used at CSU, but it can be modified for different hospitals as well as differently sized animals.