The Current State of Radiation Dosimetry in Radionuclide Therapy
- Department of Medical Physics, University of Wisconsin, Madison, WI 53705 (United States)
Radionuclide therapy combines the specificity of cancer cell targeting with the well-known cytotoxic effects of ionizing radiation. It has the potential to simultaneously eradicate both the primary tumor site as well as the metastatic extent of the disease throughout the body. Despite these advantages, a major limitation of radionuclide therapy is that conventional internal dosimetry methods have failed to accurately predict treatment outcomes in patients. It has been proposed that this shortcoming is due to the fact that therapeutic dosimetry is typically performed using methods developed for diagnostic imaging that do not consider patient specific anatomy, pharmacokinetics and dose heterogeneity. Even worse, dosimetry methods are often completely neglected during treatment planning and dose prescription is based on Body Surface Area/Weight (BSA/BW) and platelet counts. The most widely used internal dosimetry software is OLINDA/EXM (Organ Level Internal Dose Assessment for Exponential Modeling). OLINDA/EXM calculates absorbed doses using the formulism developed by the Medical Internal Radiation Dose (MIRD) committee of the Society of Nuclear Medicine. In its current implementation, OLINDA/EXM requires the use of S factors, which are derived in phantoms that do not accurately represent the actual patient. In addition, OLINDA/EXM assumes that the activity distribution in each organ and tumor is uniform, when it has been well established that activity distributions are often highly heterogeneous. Furthermore, the tumor is not modeled in the phantom, which introduces additional uncertainties in the calculation. Due to these limitations, there is a clear need for improved dosimetry methods for therapeutic nuclear medicine that utilize patient-specific imaging information. A variety of efforts are currently underway to develop such methods. There are two commercial software packages on the market for voxel level internal dosimetry: STRATOS (Philips Technologies, Aachen, Germany) and VoxelDose (DosiSoft, Cachan, France), but both packages are not widely used in clinical practice. In addition, several academic platforms have been developed. Similar to these offerings, RAPID is a robust, fast and multimodal platform. However, RAPID has been designed with tremendous flexibility to perform accurate dosimetry for any radiopharmaceutical in the pre-clinical and clinical setting in order to aid in drug development and to assist in radionuclide therapy treatment planning. This presentation will overview existing dosimetry platforms while focusing on the Monte Carlo-based platform developed at the University of Wisconsin known as RAPID (Radiopharmaceutical Assessment Platform for Internal Dosimetry). RAPID is a robust and universal platform that can provide accurate 3D internal dosimetry for any radiopharmaceutical during both the pre-clinical and clinical stages of drug development as well as clinical treatment planning in TRT. (authors)
- OSTI ID:
- 22991820
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 114, Issue 1; Conference: Annual Meeting of the American Nuclear Society, New Orleans, LA (United States), 12-16 Jun 2016; Other Information: Country of input: France; 4 refs.; Available from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 United States; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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