A safer X-ray with XPCi
The X-ray procedures of today aren’t much different than those of yesteryear, except for the technology, which is has now gone digital and no longer relies on film. While X-rays and other medical imaging technology have saved countless lives by enabling accurate medical diagnosis, the radiation that patients are exposed to in the process can be harmful and even increase one’s risk of developing cancer. Fortunately, technological advancements in medical imaging are set to reduce this risk.
As it stands now, if an X-ray of body systems other than the skeletal system are required, a radiocontrast agent must be administered to the patient. For example an X-ray of the intestines requires a patient to ingest barium sulphate, which binds to the organs and increases their visibility. Other imaging methods, such as computed tomography (CT) scans, sometimes require that a patient be injected with iodine preparations, ethiodol or gadolinium in order to increase visibility of organ structures. Some contrast agents can put stress on the kidneys, in some cases too much, resulting in harm or even killing very weak patients. CT scans in particular result in patients being subjected to such high X-ray doses that they are placed at increased risk of developing cancer, simply so that their doctors can diagnose other ailments.
One possible solution to the dangerous side effects of existing medical imaging technologies could be X-ray phase-contrast imaging (XPCi). Unlike the X-ray technology currently in use, XPCi doesn’t measure X-ray intensity; instead it measures the change in the X-ray’s phase. X-ray waves move slower through muscle than they do through fluids and more delicate structures. For example, an X-ray wave front will pass through a lung sac, which is composed mostly of blood vessels and air, quicker than it will pass through the heart.
The use of XPCi technology does not require the introduction of toxic contrast agents to the patient’s body. Additionally it requires a lower X-ray dosage and can be used for imaging not only the skeletal system, but also internal organs and can even detect internal bleeding.
Mark Eaton, CEO of Stellarray, was quoted, “People are getting more and more CT scans. The doctors love them because they can get a better diagnosis, but the radiation dose is getting to be too high, and phase-contrast imaging is fundamentally different. What you’re detecting is the phase change, not the absorption. It is a profound level of dose reduction, by one to two orders of magnitude.” Eaton said Stellarray is developing a XPCi imaging device but declined to disclose specific details.
One thing that Eaton failed to mention about medical imaging’s popularity among doctors is the artificially inflated costs of such procedures, especially in the U.S. While ethical and competent physicians most certainly enjoy the enhanced view, most U.S. docs simply enjoy charging between $900.00 and $12,000.00 for a procedure that might actually cost between $100.00 and $500.00. It’s for this reason that American patients often find themselves frightened or bullied into enduring unnecessary medical imaging procedures.
Conventional X-ray machines produce a varying range of X-ray wavelengths that travel from different points and in different directions. XPCi technology is more complicated, and till date was available only from powerful X-ray sources such as giant particle accelerators.
According to Luis Fernando Velasquez-Garcia, principle research scientist at MIT’s Microsystems Technology Laboratories, “What you really need is basically something like a laser, but for X-rays.”
While particle accelerators are deemed the best source of XPCi X-rays, the good news is that particle accelerators are shrinking. Some have been miniaturized to fit onto chips, and one development we can look forward to is a tabletop chip-based system being developed by Velasquez-Garcia and his team at MIT and Massachusetts General Hospital.
The team has developed a chip that contains microscopic electron emitters, each of which sends beams of electrons from a nanometer-sharp metal tip to a high-voltage electric field, which in turn accelerates the the beams before they collide with a thin gold film to result in the emission of an almost completely monochromatic X-ray beam.
Heinz Busta, who chairs the steering committee of the International Vacuum Nanoelectronics Conference, says he’s recently witnessed a heightened interest in XPCi, and that engineers in China, South Korea, Japan and Europe are also working on technologies similar to what is currently under development at MIT. Busta said, “For nondestructive testing, sterilization, homeland security, medical imaging, there are huge applications, and not only new applications but safer applications.”