RADAR - Available Phantoms

You want phantoms, we got phantoms. RADAR has developed an entire new generation of human body models, to replace the 'stylized' ORNL phantoms of the 1980s and 1990s. The older models look like this.....:

RADAR's totally cool new ones that look like this.....:

Fetus don't fail me now.....

Dr. George Xu of Rensselaer Polytechnic Institute has organized a site which compiles and distributes information about the many new phantoms that are being developed by a number of groups, called the Consortium of Computational Human Phantoms (CCHP)

History of Phantom Development

For those of you who may have skipped over the initial overview of the system, and don’t know, a phantom in the context of internal and external dose assessment is a mathematical representation of the human body used to calculate the Dose Factors (DFs) that we need to convert disintegrations in some source region to absorbed dose in a target region. To model anything - the human body, a cell, a city, etc. - one always starts with a sphere, because it’s so simple mathematically. A great book on the subject of modeling was actually called "Consider a Spherical Cow" by John Harte (see web page). In the late 1950’s we did have a spherical human, with lots of little spherical organs. Easy to calculate numbers with, but not too realistic. Then, in about 1975, a phantom was developed that was supposed to represent an average adult worker of the Western Hemisphere, based on the so-called (and completely politically incorrect) Reference Man, so dubbed by the International Commission on Radiological Protection (ICRP). The ICRP didn’t design the phantom, they just collected the data on the typical sizes of people’s bodies and their organs, and two guys at Oak Ridge National Laboratory named Fisher and Snyder (the latter being Walt Snyder, who basically founded and ran the MIRD Committee for many years) designed a phantom based on Reference Man and ran a Monte Carlo code whose results were used to calculate DFs for all the organs in this phantom irradiating all the others (which, interestingly, contained both male and female organs - a mind bender, ain’t it?).

OK, this did well for some time in calculating doses to adults, but in nuclear medicine as well as other applications we quickly found the need for phantoms representing other people. In 1987, Cristy and Eckerman published a very important work in which they described six phantoms representing children and adults. These six phantoms were designated as a Newborn, One-Year-Old, Five-Year-Old, Ten-Year-Old, Fifteen-Year-Old and an Adult. The adult was very similar to the Fisher-Snyder phantom, but had some minor modifications, and included some organs that the Fisher-Snyder phantom did not. All of the phantoms had both male and female organs. The age designations were meant to be approximate - Cristy and Eckerman researched the changes of organ size, position, and composition with age and, like the Reference Man document, catalogued what they felt were the appropriate values to use as averages for that age. Of course some children grow faster or slower than others - one can envision a 5-yr-old who is as big as the 10-yr-old phantom; in this case, the 10-yr-old phantom should probably be used, as what we are after is energy absorbed per unit mass (dose), and the important issue is probably mass. In any case, the idea was to give a set of phantoms that would span the size of people from infancy to adultery, I mean adulthood, and which could be used to calculate dose estimates for a range of people of different sizes.

By this point in our presentation about half of you are probably upset, because we are not giving enough consideration to the stronger sex. Women were somewhat slighted in all of this, as they were slighted in the workplace for so long. Although the Fisher-Snyder and Cristy-Eckerman phantoms had female organs, they were pretty much built around the average male for that age. The Cristy-Eckerman 15-year-old phantom was used for many years as a surrogate for an adult female, but who wants to have a surrogate representative? In 1995, Stabin and colleagues put out a document similar to the Cristy-Eckerman document, but with a series of 4 phantoms representing the adult female - the first was just a standard adult female (with several notable differences from the Cristy-Eckerman 15-year-old phantom) and the other three represented the woman at various stages of gestation, as dose to the fetus is such an important issue in both nuclear medicine and other areas.

So as of this date, one could argue, we have a more or less complete ‘family’ of phantoms - just like a real household - kids running around screaming, dad sitting there doing nothing, several pregnant women (all right, a strange household perhaps, but is yours, like, perfectly normal?). If you want to see the SAFs for any phantom, you can check them out them here: