### OpenDose software

Reference dosimetry
OpenDose Calculator
Personalized dosimetry
OpenDose 4D

Dosimetry in Nuclear Medicine (diagnostic or therapy) can be implemented using the methodology introduced in the late 60s by the Medical Internal Radiation Dose (MIRD) committee of the American Society of Nuclear Medicine (SNM). This methodology, known as the MIRD formalism [1] can be expressed as: $\overline{D}_{Target} = \sum_{Source} \widetilde{A}_{Source} \times S_{\left( Target \leftarrow Source \right)}$ where $$\overline{D}_{Target}$$ is the absorbed dose (Gy) delivered to the target (organ or tissue), $$\widetilde{A}_{Source}$$ is the cumulated activity (i.e. the total number of disintegrations, Bq.s) occurring in each source (organ or tissue) and $$S_{\left( Target \leftarrow Source \right)}$$ is the mean absorbed dose in a target per nuclear disintegration in the source (S value, Gy.Bq-1.s-1). This formalism separates the determination of the absorbed dose in two independent tasks: the estimation of the cumulated activity $$\widetilde{A}_{Source}$$ and the calculation of the S value. S values are obtained for a specific human model and for a given radioisotope, and can be expressed as: $S_{\left( Target \leftarrow Source \right)} = \sum_i y_i E_i \Phi_{i \left( Target \leftarrow Source \right)}$ where $$\Phi_{i \left( Target \leftarrow Source \right)}$$ is the Specific Absorbed Fraction (SAF, kg-1) for radiation type i and $$y_i$$, $$E_i$$ are the yield (Bq-1.s-1) and energy (J) of radiation type i, respectively. The calculation of SAFs is done through intensive Monte Carlo simulations of radiation transport in the human model, for every particle type (photons, electrons) and energy.