The explosive growth of PET machines.

In year 2001, there were only one PET scanner in greater Montreal area. Today, there are seven--five in public hospitals, and two in private clinics. Why the explosive growth? Cost, of course. As PET/CT combined scanner got introduced to the market, the scanning time required for each patient cuts in half. The availability of CT images also provided much better anatomical reference for the PET images, which provide functional information. Of course, the installation of specially designed medical cyclotron doesn't hurt either. As turn-key devices, medical cyclotrons produce FDG's needed by PET scanner.

This growth of PET scanners makes me think about the growing popularity of digital SLR cameras. Yep, not much similarity between the two devices, but similar economic principle. As price of digital SLR cameras dropped below $1000, they became popular. As popularity grows, manufacturers ramped up production, and further reduces prices. Of course, this in turn causes more people to buy something that was reserved for serious hobbyists. The end result is a huge growth in total dollar amount of dSLR's sold. Same thing in PET/CT scanners. As costs per patient drop, the increase in number of scans more than make up for it. The end result is a fast growing segment of the industry.

Unlike pure research, the cost per patient will always be a deciding factor in health care.

Nuclear medicine making a come back?

During my undergrad, when people talk about Medical Physics, they assume it's either external beam radiotherapy, or CT/MRI imaging. Sometimes Health Physics is included. Rarely was nuclear medicine mentioned. But apparently, with the introduction of PET/CT combined scanner, nuclear medicine as its own specialty is making a come back. The use of radioactive source and x-ray imaging requires a special type of Physicist, the Nuclear Medicine Physicist. Until now, the role and responsibility of Nuclear Medicine Physicist is not yet well defined, but we should see changes in this area soon. In external beam therapy, for example, various protocols have been established by either AAPM or ICRU to define the required treatment quality as it pertains to physics. We may expect to see similar things being introduced to Nuclear Medicine, specifically to PET/CT scanner.

On LSO scintilation crystal

Like almost any technology, medical devices go in and out of vogue all the time. One thing I find worth noticing is the growth in Nuclear Medicine due to the introduction of PET/CT imaging. Just like IMRT spurred explosive growth in external beam radiotherapy, PET/CT scan promises to do the same to nuclear medicine imaging. One of the technologies in development is LSO scintillation crystal, used in PET detectors. Compared to older BGO crystals, it has certain merits. The raw source, Lutetium, cost about six times as much as gold. Considering that scintillation crystals are macroscopic sized, the cost of raw element would be considerable.

Lutetium is a rare earth element, commonly found with other Lutetium. As I learned in grade school, China is a major exporter of rare earth elements. (Can you tell I'm Chinese? It's one of the few things I learned in the Communist brainwashing.) Chances are, most Lutetium in the world is produced in China. Another example of the interdependence of global economy. China can't produce LSO based detectors, but it produces the raw material, and uses the devices produced.