Achieving painless dental imaging
Andy Wilson Editor at Large
My recent trip to a craniofacial dental surgeon for the removal of several teeth raised a concern about analog x-ray imaging. During the first dental step, the surgeon took an x-ray of my head using a panoramic radiography machine. Minutes later, he analyzed the x-ray film displayed on a light box, and then he wrote a medical diagnosis report.
As an editor of a magazine that covers medical image-processing techniques, I find x-ray film somewhat lacking in visual details. Despite this, I peered over the x-rays with the doctor as he pointed out certain imaging characteristics. To avoid any discussion about my teeth, I asked him whether he had ever thought of digitally automating his x-ray procedure to obtain a more detailed analysis and to save the time and materials associated with film-based imaging techniques. His argument was that if the system wasn`t broken, why should he fix it.
How could I the sell the doctor on digital imaging? I went away, consulted the Web, and came up with what I thought was the proper imaging system. Initially, the x-ray film is digitized using a high-resolution film scanner. Then, a contrast-limited adaptive histogram equalization (CLAHE) process is used to highlight the imaging features of interest. From such images, the dental surgeon would be able to better visualize teeth, bones, cavities, and decay. These images would help the doctor make a better diagnosis and, therefore, enable better surgical results.
On paper, it all seemed great. What surgeon could resist? But, upon reflection, the benefits of my idea became tempered by traditions, governments, and lawyers. For years, physicians have read x-rays and interpreted data based on film images and shadow effects. And, because physicians have not been educated in digital imaging-processing in medical school, they would probably require further training.
Device approval
In the United States, the lengthy Food and Drug Administration device-approval process usually means that new medical-imaging equipment is slow in coming to market. And upgrading such systems must also be approved by government agencies. Operations such as CLAHE change pixel values within images in an adaptive way. And although the resultant image may be easier to use for diagnosis, it is no longer the original image. If a diagnosis is made on an altered image and then proven incorrect, the patient may have grounds for legal action.
Perhaps the United States should adopt the same image-analysis standards that are prevalent in Denmark. There, image-enhancement techniques can be performed on images, and the physician can make a diagnosis from them. The results of using both original and enhanced techniques are then documented in a report that describes how the physician arrived at the specific diagnosis.
Such standards and documents safeguard both patients and physicians alike, should any disagreement arise. Better yet, such standards ensure that image-processing analysis systems and techniques can be rapidly adopted. However, in the United States no such standards currently exist. And, until they do, the development, deployment, and use of dental digital image-processing equipment will be as difficult as pulling teeth.
