Nuclear medicine is the second largest source of medical radiation exposure to the general population after computed tomography imaging. Imaging modalities utilizing nuclear medicine produce a more detailed view of internal structure and function and are most commonly used to diagnose diseases such as heart disease, Alzheimer’s and brain disorders. They are used to visualize tumors, abscesses due to infection or abnormalities in abdominal organs. When using radionuclides for diagnosis or therapy in nuclear medicine, it is critical to accurately estimate unintended dose to organs at risk surrounding tumors or of therapeutic or imaging interest. It is impossible to experimentally measure organ dose. Traditionally, computational approaches were used for this purpose, requiring a series of computational human phantoms and an extensive amount of computer simulation. However, existing model-based organ dose estimation tools rely on simplified human anatomy models or commercial programs.
To address these challenges, Dr. Choonsik Lee from the NCI created a radiation dose-calculation tool for nuclear medicine imaging modalities based on more sophisticated human anatomy models. A comprehensive library of photon and electron specific absorbed fractions (SAF) were first calculated for multiple combinations of source and target regions within a series of pediatric and adult computational human phantoms matching the International Commission on Radiological Protection (ICRP)'s reference data. These were combined with a Monte Carlo radiation transport code. Then, a library of S values was derived from these SAFs and the nuclear decay data from ICRP Publication 107. Finally, a graphical user interface, named the National Cancer Institute Dosimetry System for Nuclear Medicine (NCINM), was created to facilitate the dosimetry process. Approximately 13 million S values were derived from 2 million SAFs computed. A comprehensive library of biokinetic data were extracted from multiple up-to-date international reports and implemented into NCINM.
Applications of the NCINM program include computation of absorbed doses for use in radiation epidemiologic studies and patient dose monitoring in nuclear medicine. The NCI seeks licensees for this technology who are interested in using NCINM, including their implementation within existing commercial solutions for patient dose monitoring.
- Easy implementation within existing commercial solutions
- Most advanced pediatric and adult computational phantoms
- Intuitive user interface
- Software can run on Macintosh, Windows, and LINUX operating systems
- Patient radiation dose monitoring in nuclear medicine imaging modalities
- Radiation epidemiologic studies
- Components can be incorporated with NCIDose software into a commercial platform: NCINM program, computational human phantom series (human anatomy models, electronic files), organ dose factor library (tabulated numbers)