Medical Physics Seminar – Monday, March 26, 2012
Improved Dosimetry for 90Y Microspheres Treatments of Liver Malignancies
Adam Paxton (student of Dr. Larry DeWerd)
Research Assistant, Department of Medical Physics, UW-School of Medicine & Public Health, Madison, WI - USA -
90Y microsphere treatments of liver cancers have shown promising results, including increased
survival rates and the potential to downgrade the disease state to resectable (i.e., curable).
However, there is presently no national standard for 90Y microsphere activity. Users are reliant
on manufacturers to provide activity data and these given values have large
uncertainties (~10%) and may not be accurate. This leads to the inability to correlate clinical
outcomes with the dose received by the patient, meaning this treatment remains largely unoptimized.
This work describes the construction and characterization of a coincidence detection system for
assaying the activity of a 90Y microsphere sample. This device could be used as a standard to
calibrate well-type chambers (or dose calibrators) for more accurate clinical determinations of
sample activity, which would contribute toward lowering the
dosimetric uncertainty associated with this treatment.