we just need terms for N_S and for DF. Values for N_Swill vary from problem to problem. Where a nuclide or pharmaceutical concentrates in the body depends on its chemical characteristics. The number of disintegrations depends on this as well as the physical half-life of the radionuclide. However, most of these values are tabulated for many standard cases. For new situations, one has to calculate the values, and this is a lot of work. But if you just want to look up or experiment with values for well known problems, we have set up tables of N_S values. In occupational situations, the ICRP, in various publications, has established good values for N_S for many nuclides (they call them U_S – don't ask me why), and we have just brought them in here. For radiopharmaceuticals, there are a number of sources - MIRD Dose Estimate Reports, an NRC document put out by the dose assessment group at Oak Ridge, a number of documents by the ICRP, and various other free standing publications. We have pulled together what we think are the best current models for many popular radiopharmaceuticals, and tabulated values of N_S for you.

One of the problems here is that people don't always agree on these models, and the models change periodically, as new kinetic information becomes available. We don't claim that these numbers are cast in stone, are the only ones available, or won't change. As a matter of fact, we welcome information that will change these numbers, as models improve. If you have information that can contribute, please let us know. But at any time, we will keep what we believe is the best available information on the site for your immediate use.

Now, the DFs. The DFs are established, typically employing Monte Carlo codes to tranport millions of particles in standard models of the body (called phantoms) and catalogue their average behavior. Currently, there are a good number of standard phantoms available, and we have brought in the DFs from these models to be used here. As with the kinetic models, at times models improve, new models are added, etc. If you have information that we should use, let us know! Currently, there is much work going on to replace the standard phantoms of the past 25 years, which were based on equations, with new standard phantoms based on voxel scans of actual individuals. RADAR is currently developing new DFs for both internal and external sources using these new phantoms, and as they become available and are tested out to be OK, we will immediately put them on the site.

But the great part is that we are going to use one system for all applications, so that you don't have to read and learn dozens of documents to work with dozens of applications. You will use the simple equation above (we will do all the work to keep the stuff straight inside of the DFs – just trust us, we're scientists!), and you just need to figure out how to either understand (for established situations) or enter (for new situations) values of N_S. For external or internal sources (here, for occupational or nuclear medicine applications), and just put in the value(s) of N_S that you need, choose the phantoms of interest, and you can access dose values easily.  For more specific applications, involving data fitting, patient-specific doses, etc., we are developing some software packages that will run on your personal computer.

What about the decay data?

Let's see those kinetic models

Let's see those phantoms

Overview of the External Dose Assessment System