Friday, 16 March 2018

Bone scan

This is one of the Discovery NM/CT 670 SPECT/CT machines at Kingston General Hospital. It's a combination of a gamma ray camera (Single Photon Emission Computed Tomography) and CT scanner (also Computed Tomography, repeated because there are two parts to the machine). I had a bone scan this morning, and found the technology fascinating.

(SPECT/CT machine)

The SPECT part is the two flattish pieces sticking forward of the donut; the donut is the CT. The flattish piece on the right is the gamma ray emitter; the the one on the left is the sensor.

About two hours before the scan I had a brief (and tiny) injection of a radioactive dye; it binds to crystalline structures indicating bone growth, which occur near fractures, lesions, and metastatic cancers. These then show up as bright spots in the gamma ray image.

The first image was taken with the SPECT rotated so the sensor was slightly inclined from the horizontal, so I could rest my arms on it while standing beside the machine. After that, I lay on the horizontal bed, which can move up and down, and into and out of the machine to position me for the rest of the scans. 
(Me lying on scanner bed with arm and foot restraints)

It takes about three minutes for each image, so they used some velcro restraints to give support to my arms and legs to make it easier to keep still. Then they positioned me with my head between the emitter and the scanner for three minutes, which I thought would trigger my claustrophobia but which was easy to tolerate with my eyes closed. Then over another twelve minutes they slowly moved me out of the machine to get an image of my whole skeleton. 

 (Me slowly being moved left out of the machine)
Next was a three-minute head scan with my head facing left, then with my head facing right.

At that point the radiologist examined the scans and decided he needed more detail of my right knee, which if I recall correctly I injured about fifty years ago; it could have a little arthritis, which can also show up on the scans.  Finally they took a 3D image of my pelvis with the SPECT -- twelve minutes of having the camera take a picture, rotate a little, and repeat -- followed by a couple of minutes of using the "donut", the CT part of the SPECT/CT. They they combine the scans for a 3D image.
(Me positioned with my arms over my head for the 3D pelvis scan)

Throughout the procedure my wonderful wife Margaret kept me company, helping me avoid both boredom and panic; she also took all of these pictures.

We talked a little with the technologist running the machine; she had a 4-year university degree in anatomy and other medical subjects, followed by a 3-year diploma.

The whole thing was sufficiently fascinating that I was sometimes able to ignore the fact that the whole process is looking for possible metastasis of my prostate cancer to my bones, which would shorten my life expectancy considerably. It's a very small chance, but they have to check. The radiologist and the technicians don't tell the patient anything about the results; the report has to go to the doctor who ordered it.

I will see the oncologist on Tuesday morning.