ABSTRACT
The absorbed dose calculation is one of the last steps of the clinical dosimetric workflow, after activity determination, time-activity curve fitting and the determination of time-integrated activity (TIA).
Pre-computed, model-based dosimetric parameters such as the S values (absorbed doses in a target volume per disintegration in a source volume), designed for risk assessment of diagnostic procedures have been used in clinical dosimetry for several decades.
Patient-specific dosimetry has emerged as a necessity in the context of targeted radiotherapy. It usually requires image-based activity determination associated to patient specific geometry assessment. Then, several absorbed dose calculation algorithms are possible, derived from the simple assumption that energy is locally absorbed to the explicit modelling of radiation transport in heterogeneous media using complex Monte Carlo codes.
The development of patient-specific dosimetry is now accessible to a wider audience with the growing availability of dosimetry workstations which are becoming widely commercially available. The absorbed dose calculation step has therefore evolved from being restricted to a limited number of specialised centres to being widely available in the clinical environment.
This chapter describe the methods that can be used for patient-specific dosimetry and the advantages and disadvantages with each of them.
