Mom! Why is there blood in my X-Ray?

Graphic Images: Viewer discretion advised

Whether it be a dentist checkup, broken bone or a really bad cold, I think we have all gotten an X-ray before. But have you ever wondered why the images are always in black and white?

Traditional X-rays work by sending a high energy beam of “light” through tissue. Denser material, like bone, block more of the x-ray beam and thus appear to be lighter in color. Softer materials, such as that water that makes up most tissues, readily allow x-rays to pass through and thus appear darker. This single measure of electron density generates 1D black and white X-rays that we see.

Up until recently, there was no method to obtain colorful x-rays with additional information.

Color x-ray of a wrist and wrist watch with red for tissue and white for bones. (Image: MARS Bioimaging Ltd)

In a partnership with CERN (European Organization for Nuclear Research) and over 20 other research institutes, MARS Bioimaging Ltd. has just generated the first color x-ray image of a human being.

Using various wavelengths of X-rays that each pass through different types of tissue in different ways, a fully detailed image with much more information about tissue properties can be generated using deconvolution algorithms.

3D color x-ray image of ankle and foot. Image from Google

“Color” can then be associated with tissue properties to generate the vibrant x-ray images we see above.

This imaging modality, called Spectral CT, utilizes technology from CERN- specifically the Medipix3 chip- to distinguish the energy and wavelength of every single particle that hits its sensor.

Originally developed to track high energy particles in the Hadron Particle Collider, the Medipix3 chip’s accurate pixel and energy resolution enables highly detailed tissue information to be collected. More information on the Medipix3 chip can be found here.

Pixel individualized proton counting technology of Medipix chips. Image from Wikipedia

Combining all of this technology, this novel imaging device is called the MARS spectral x-ray scanner.

In addition to being a major wow factor, MARS Bioimaging Ltd. hopes that these detailed images with more information on tissue properties can help physicians better identify certain diseases, such as cancer, at an earlier stage.

“As a new imaging device, a new microscope if you like, biomedical researchers can non-invasively see different kinds of detail inside patients,” says Phil Butler — Professor and one of the creators of the MARS spectral CT

Creators of MARS spectral X-ray scanner, Phil Butler (right) and Anthony Butler (left)

To date, MARS Bioimaging Ltd. has disclosed $500,000 in series A funding.

My perspective:

All the coolness and “wowness” aside, I think cost is the major prohibiting factor. Sure, having colorful images of your left Triquetrum bone might be awesome to show your friends and coworkers — but would you pay $5000 out of pocket for it?

Is the additional (if any) clinical benefits of having more detailed images worth the potentially increased cost and radiation exposure?

Another thing to remember is that the coloring is artificial- the color is added post-imaging according to x-ray transmission data. This means that we are not actually seeing the red color of tissue and the white color of bone, but rather scientists’ interpretation of what should be tissue and bone.

Thus, if an imaged tumor has similar properties as tissue- it will also show up red in the colored image and be indistinguishable. In other words, while the spectral CT system may be able to generate colorful images of bone, tissue and cartilage with enough calibration — it doesn't necessarily provide more information on diseases and tumors than regular x-ray CT systems.

Reading through the detailed brochure provided by MARS Bioimaging Ltd, it seems that the system is better designed for used with traditional CT contrast agents (gadolinium, iodine, gold) for disease diagnostics.

Spectral CT combined with multiple contrast agents for multiplex imaging. Each contrast agent can be targeted to a disease biomarker. Image from MARS Bioimaging

Use of these extragenous contrast agents allows for diagnostics but opens up another can of worms with all new sets of issues that is a topic for a future article.

The bottom line is that, while this technology is really cool and the images will attract of media attention, spectral CT is likely still a whiles away from demonstrating clinical feasibility.