Decommissioning of a Medical Cyclotron using ISOCS

Scope:

RDS-112 Positron Emission Tomography (PET) cyclotron manufactured by CTI Molecular Imaging, Inc., in Knoxville, Tennessee, USA, producing F-18 and C-11 PET radiochemicals.
Operated for eight years and decommissioned in 2007.
Components ranging from 0.1 g targets to 10,000 kg concrete shields.
Activities ranged over nine orders of magnitude.

Thorough radiological characterization required for shipping and disposal.
Locate and characterize all activation hotspots.
Wide range of activation products present in activated metals and concrete, including Fe-55, Mn-54, Zn-65, Sb-124, W-181, Ta-182, Co-57, Co-60 and Cs-137.
Very limited timeframe available for measurements (2 days) and analyses (1 month).
Limited characterization budget prohibited sampling and offsite analysis.

Locate activation hotspots using handheld NaI probe, perform 100% gamma scan on all items.
Measure each hotspot with ISOCS-characterized high resolution Broad Energy Germanium (BEGe) detector and ISOCS mathematical efficiency calibration software.
Develop customized nuclide libraries for each type of activated material.
Analyze gamma spectra and generate Radioassay Data Sheet for each item.
Produce comprehensive Radiological Characterization Report to include all items.
Perform all measurements in low-background area to minimize intereferences.

All analytical results were delivered to the customer within thirty days.
100% of the cyclotron components were scanned for activation hotspots.
45 high-resolution gamma spectroscopy measurements were performed over two days in the field.
Activated items ranging from simple to very complex were modeled.
Activities over nine orders of magnitude were measured and reported.