Vintage mammography phantom

Just about every medical physicist has a collection of old test gear, phantoms, test objects ,meters and the like.

A few years ago, while rummaging through the equipment cabinet in our store room/library/lab, I came across a variant of a mammography phantom that I hadn’t seen before. Instead of the normal pink wax insert, this one had 16 wax squares of different colours.

Aside from the curved bit of plastic at one end of the phantom (a test object, not a ghostly apparition), it’s the same size as the conventional ACR accreditation phantom. Reminds me of one of those sliding number/picture puzzles where you have to slide the squares around to reconstruct the image.

I let it sit on my book shelf along with some of the other pieces in the collection. A few months ago, I decided it was time to have a look and see what the inside of the wax blocks looked like.

Looks like at some point in its history, the pieces got a little scrambled and reinserted a bit randomly. I was expecting that each colour block would represent a different density. Instead there are the usual fiber, speck, and mass groups, but not nearly as uniformly placed as in the accreditation phantom.

I don’t know how old this phantom is or what time frame it might have been used at work. The only mammography phantom I was familiar with before this one was the pink one, so possibly before 1996 at least. Definitely pre-1999.

If anybody out there happens to know anything about this style of mammography phantom, let me know.