SPECT/CT and additional radiation dose - A retrospective analysis in our department.

Since the introduction of the frst commercially available SPECT/CT system on the market in 2001, the implementation of these systems in nuclear medicine departments has rapidly grown both locally and globally. Similarly, the associated benefts of this technology in terms of diagnosis and patient management have been well communicated and documented. However, with the implementation of CT into a nuclear medicine study comes an additional radiation burden to the patient which must be justifed in line with their condition and demographics (for example age, gender, weight, etc.). The Philips Precedence SPECT/CT system is one of several on the market with adjustable CT exposure factors, and is capable of performing CT diag-nostically. This system was installed in the nuclear medicine department at Monash Medical Centre in February 2007. Since that time, the number of SPECT/CT examinations performed has risen from 92 patients in the frst 6 months to 150 in the most recent 6 month period. Alongside this, with appropriate training, physicians and technologists alike have garnered further experience and familiarity with this technology. This has seen an increase in the mean tube current from 63 to 75 milliamps (mA). The aim of this investigation was to assess the distribution of CT exposure factors across different nuclear medicine procedures. The resultant changes in diagnosis for selected patient cases will be discussed, along with other descriptive statistics for our department.