No abstract

Gamma emitting radioactive by-products generated during the cyclotron irradiation of (18)O labelled water by protons to produce (18)FDG (fluorodeoxyglucose) for positron emission tomography are well characterised. However, the production of tritium ((3)H) through the (18)O(p,t)(16)O nuclear reaction has not been investigated in detail. The aim of this study was to measure tritium activity produced during a large number of (18)FDG production runs in order to obtain a better perspective on its impact on radioactive waste management, particularly as regards storage and disposal. Tritium was assayed by liquid scintillation counting in recovered (18)O water from 24 separate production runs. The mean (SD) values of activity and activity concentration were 170 (20) kBq and 81 (8) kBq ml(-1) respectively. Both quantities were positively correlated with the activity of (18)F. Tritium was detected in much lower concentration in water used to rinse the target vessel. The activity of tritium is such that it is exempt from regulatory control and may be combined with bulk non-active waste for disposal as Very Low Level Waste. However, variations in the irradiation conditions or the procedures for the collection of recovered water might result in its classification as Low Level Waste, necessitating a more complex disposal regime.

With the increasing number and complexity of interventional cardiology procedures there is the potential of higher occupational radiation doses to interventionists. In order to reduce the radiation exposure to interventionists a number of different radiation protection measures can be implemented with the most common being personal protective equipment in the form of a lead equivalent apron. However significant development has been achieved with mobile lead equivalent radiation protection devices, providing enhanced radiation protection without the requirement of being directly worn by staff. The RAMPART M1128 radiation protection shield is one of these devices. The dose reduction provided to staff within a Cardiac Catheterisation Laboratory was assessed via use of Electronic Personal Dosimeters (EPD) with the Philips live dosimetry system DoseAware (Philips DoseAware). A 60% dose reduction to the primary operator can be achieved with the Rampart device. With further dose reductions possible for other individuals in the range of 65 to 84%. Additionally, dose rate measurements were taken in a simulated clinical set up using a phantom, which showed that the device provided a 65% dose reduction at eye level and 90% dose reduction at chest level for the primary operator position. This significant dose reduction means that there is potential for at least the primary operator to wear a lead apron of reduced lead equivalence specification when the Rampart device is in use without increasing their occupational exposure and potentially reducing musculoskeletal pain due to the reduced weight.