Radiation dosimetry in translational intrathecal imaging

Intrathecal (IT) administration is a drug delivery method with great potential for the treatment of a broad range of neurodegenerative disorders. Imaging is a useful tool for assessing the biodistribution of intrathecally administered molecules, especially for longer-lived radionuclides. However, longer-lived radionuclides are often associated with higher radiation absorbed dose, a quantitative measure computed from serial imaging data. We have developed a custom dosimetry model to support intrathecal administration. In this work, emphasis is placed on recent model refinements to improve absorbed dose estimates to the spinal cord and its implication for dosimetry calculation in translational imaging trials.