I realise that his blog is way out of date - I'm so sorry, it's been a crazy few months. I'll get onto it soon, I promise ;-) xxx
Anyway, I think it's easier to post the scan pics here, if people want to look at them.
This type of scan is called a Gallium PET scan and is very specific. If the Neuroblastoma cells have receptors, they will light up. Red being more intense = more active disease.
However, not all red spots (or black from the 1st pic) are cancer. Some of the normal organs like the spleen and bladder also take up the tracer that is needed for the scan. Hence the "red/black" blobs that appear big on the scan.
The main areas are his bones - pelvis, legs, arms, spine and skull. If you concentrate on those areas, you can see a HUGE improvement in less than 4 months :-)