Dosimetry in Molecular Radiotherapy for Personalized Patient Treatments

Radiopharmaceutical therapy (RPT) can be broadly defined as the use of radionuclides to deliver radiation lethal to tumour cells. Radiation delivery in RPT involves the use of pharmaceuticals that either bind specifically to tumours or accumulate by a broad array of physiologic mechanisms. The efficacy of RPT depends upon delivering a lethal level of radiation to tumour cells while sparing normal cells. The ability to image the biodistribution of RPT agents and use this information to evaluate the absorbed dose has been seen as an unnecessary logistical and financial expense of the treatment. However, in the context of drug development and optimization, the ability to image and calculate normal organ and tumour absorbed doses, provides a number of advantages because these variables are more closely related to biological response. A dosimetry-driven treatment-planning approach to RPT translates into accounting for patient-specific pharmacokinetic and tumour and normal organ radioactivity localization differences by imaging. Such differences in absorbed dose estimates are considered which, in contrast to the amount of radioactivity administered (activity), account for individual patient pharmacokinetics, the properties of the radionuclide, and organ anatomy. Internal dosimetry is generally not integrated in the clinical practice mainly due to a lack of standardized methods, training and resources. Under the framework of the CRP participants are expected to (i) contribute to the coordinated research activities, designed to test and standardize dosimetric methods and assess the typical accuracy with which dosimetry can be reached in nuclear medicine practice and (ii) propose individual research activities in the field of dosimetry for RPT that are of local interest. Through this CRP, participants will develop abilities to be engaged into state of the art research in the field of dosimetry in RPT, with a direct impact to both the clinical services and the research potential of the Member States.