Targeted radionuclide therapy (TRT) and
radioimmunotherapy (RIT) are at the forefront of molecular cancer
treatment modalities that involve the use of cancer cell-targeting
radiopharmaceuticals, such as radiolabeled antibodies. Y-90 based
therapy has thus far been hampered by the inability to accurately image
and quantify the distribution of Y-90 within the body as the latter is a
pure b emitter. Quantitative Y-86 PET imaging allows personalized
patient treatment by enabling tailored Y-90 TRT based on the
quantitative biodistribution of Y-86 uptake but presents unique
challenges as it requires compensation for many physical effects
including gamma cascade that greatly affect image quality and accuracy.
We are accurately modeling the physics of PET imaging using isotopes
with cascade gammas, and developing correction algorithms to achieve
quantitative Y-86 PET dosimetry.
Zhu X.and El Fakhri G. Monte Carlo modeling of cascade gamma rays in 86Y PET imaging: Preliminary results. Phys. Med. Biol. 2009: in press.