Implementation of a Monte Carlo dosimetry method for patient‐specific internal emitter therapy

Abstract

In internal emitter therapy, an accurate description of the absorbed dose distribution is necessary to establish an administered dose-response relationship, as well as to avoid critical organ toxicity. This work describes the implementation of a dosimetry method that accounts for the radionuclide decay spectrum, and patient-specific activity and density distributions. The dosimetry algorithm is based on a Monte Carlo procedure that simulates photon and electron transport and scores energy depositions within the patient. The necessary input information may be obtained from a registered set of CT and SPECT or PET images. The algorithm provides the absorbed dose rate for the radioactivity distribution provided by the SPECT or PET image. The algorithm was benchmarked by reproducing dosimetric quantities using the Medical Internal Radionuclide Dose (MIRD) Committee's Standard Man phantom and was used to calculate absorbed dose distributions for representative case studies.

Three-Dimensional Radiobiologic Dosimetry: Application of Radiobiologic Modeling to Patient-Specific 3-Dimensional Imaging-Based Internal Dosimetry

“…Patient-specific 3D imaging-based internal dosimetry is a methodology in which the patient's own anatomy and spatial distribution of radioactivity over time are factored into an absorbed dose calculation that provides as output the spatial distribution of absorbed dose (3)(4)(5)(6)(7)(8). This method accepts as input a CT image of the patient and one or more SPECT or PET images.…”

“…In this work, we describe an extension of this methodology that incorporates radiobiologic modeling to account for the spatial distribution of absorbed dose and the effect of dose rate on biologic response. The methodology is incorporated into a software package, called 3D-RD, for 3D radiobiologic dosimetry.Patient-specific 3D imaging-based internal dosimetry is a methodology in which the patient's own anatomy and spatial distribution of radioactivity over time are factored into an absorbed dose calculation that provides as output the spatial distribution of absorbed dose (3)(4)(5)(6)(7)(8). This method accepts as input a CT image of the patient and one or more SPECT or PET images.…”

Internal Radiation Dosimetry: Models and Applications

“…Known the three-dimensional map of tissue density and composition from CT scan and the volume distribution of the cumulated activity through SPECT or PET emission tomography, it is possible to generate a fixed number of decay events statistically distributed in space according to emission tomography data within the patient's body reconstructed from CT and track all the emitted secondaries in order to calculate the geometrical distribution of energy deposition, i.e. the three-dimensional map of absorbed dose, and finally to rescale the results to the actual values of cumulated activity (Furhang et al, 1997).…”

Patient-Specific Dosimetry and Radiobiological Modeling of Targeted Radionuclide Therapy Grant - final report

“…Patient-specific, 3D-image based internal dosimetry is a dosimetry methodology in which the patient's own anatomy and spatial distribution of radioactivity over time are factored into an absorbed dose calculation that provides as output the spatial distribution of absorbed dose (3)(4)(5)(6)(7)(8)(9). This is accomplished by accepting as input a CT image of the patient and one or more SPECT or PET images.…”