Why DosiTest ?

Molecular radiotherapy (MRT) consists in destructing tumour targets by radiolabelled vectors. This nuclear medicine specialty is being considered with increasing interest for example via the success achieved in the treatment of non-Hodgkin lymphomas by radioimmunotherapy.

One of the keys of MRT optimization relies on the personalisation of absorbed doses delivered to the patient: this is required to ascertain that irradiation is focused on tumour cells while keeping surrounding healthy tissue irradiation at an acceptable – non-toxic – level.

Radiation dose evaluation in MRT requires the localization of injected radioactive sources by scintigraphic imaging, both in space (within the patient) and time (pharmacokinetics). Besides, absorbed dose calculation must be carried out with regards to propagating media, emitted radiations and their interactions within the patient.

Global clinical dosimetry accuracy relies on the accuracy of each of these steps. The current situation is that of a wide heterogeneity of implemented dosimetric approaches.

There is no reference, standardized dosimetric protocol to date.

One of the difficulties is how to evaluate the accuracy of the complete chain that leads from scintigraphic acquisition to absorbed dose calculation. Even though it may be possible to validate experimentally some aspects of image quantification via test objects, the absorbed dose within patient's tissues cannot be experimentally evaluated in situ.

   The project DosiTest aims at evaluating the impact of the various steps that contribute to the realization of a dosimetric study, by means of a virtual multicentric intercomparison based on Monte-Carlo modelling.