Many people are familiar with heart stent medical procedures. In fact, U.S. President Bill Clinton had a stent procedure performed in February 2010. Tens of thousands of these procedures are performed each year in Canada alone.
The stent is typically a small tube that is placed within a coronary artery to expand the vessel and permanently displace a blockage (for instance, due to plaque). A stent procedure often follows a balloon angioplasty. Insertion and installation of a stent is a minimally invasive procedure because the stent is fed in through an artery elsewhere in the body and gently guided to its final destination around the heart muscle. Stents have other applications around the body as well.
Inserting a stent is bit like finding your way through a maze and the interventional cardiologists who perform the procedure are exceptionally trained and experienced. One of the tools they use in this procedure is fluoroscopy—a technology that takes a high-resolution x-ray image of the entire body multiple times per second to give the doctor nearly real-time feedback on the procedure. Fluoroscopy is also used in other minimally invasive medical procedures such as vascular applications, neurological studies, or electro-physiology.
There is an unintended consequence of fluoroscopic imaging: both the patient and doctor receive enhanced levels of radiation during the procedure which can sometimes take hours. Strategies to reduce this side effect have been discussed and studied for at least a decade (see this article or this one). Radiation-induced heath risks in patients undergoing fluoroscopy, such as skin burns, have been recognized for many years. Furthermore, medical staff performing fluoroscopy have been prone to back-related injuries from prolonged use of heavy lead aprons to protect themselves from radiation exposure. Recent research of fluoroscopy procedures has also demonstrated an increased risk of radiation-induced cataracts for medical staff and cancer in patients, promoting discussion on occupational hazards and better regulatory mandates in fluoroscopic procedures.
Enter Advanced Applied Physics Solutions, Inc., (a federally supported Centre of Excellence for Commercialization and Research launched from TRIUMF) and several talented entrepreneurs in Vancouver: Dan Gelbart, Dr. Sam Lichtenstein, and Dr. Lindsay Machan. Working with Meir Deutsch at AAPS, this inventive trio has developed a prototype technology that would autonomously and selectively shutter the x-ray source reduce exposure to the patient while preserving high-resolution imaging in the region of interest near the tip of the toll in use. The team has formed IKOMED Technologies, Inc., with the explicit goal of commercializing and deploying this technology for marketing in surgical clinics around the world.
Existing pulsed-fluoroscopy systems expose a certain area (field-of-view) of the patient's body to a series of short X-ray pulses that capture an image time-series at the detector and present them to the surgeon as a fluoroscopic movie. In most cases, the surgeon performing the procedure is interested in a smaller region within the full field-of-view, where the eye focuses--such asaround the tip of the stent. The surrounding area of the image, while required for the purpose of orientation, is of less importance. This region-of-interest is primarily limited to the area around the tip of the catheter, or the device being used during the procedure.
IKOMED's technology is based on an innovative, patent-pending, fast-moving lead shutter that is automatically adjusted in size and position before each X-ray exposure pulse. The shutter and supporting mechanisms are used to create an image with a region-of-interest that is exposed at a standard level of radiation, while the remaining parts of the image are produced by a lower radiation dose. This advancement reduces the amount of radiation exposure to the patient and scattered radiation to medical staff.
IKOMED's product is an integrated hardware and software solution that complements the existing fluoroscopy equipment of leading medical imaging manufacturers. The technology results in up to ten-fold reduction of ionizing radiation exposure during fluoroscopy, responding to radiation safety concerns expressed by patients, medical staff and regulatory bodies.
The IKOMED team predicts that it will take several years for their radiation-exposure reducing technology to reach full market capability. Having completed the first round of financing, the company is off to a strong start. A number of fluoroscopy vendors have expressed interest in the technology and IKOMED looks forward to working with them to demonstrate the system's efficacy in full-scale fluoroscopy systems soon. Clinical demonstrations are expected before the end of 2012.
Stay tuned as this venture proves it value and offers real benefits to patients in Canada and around the world.
--by T.I. Meyer, TRIUMF's head of strategic planning & communications, with assistance from M. Deutsch
Additional reference on radiation risks to x-ray techniciaions: http://www.xraytechnicianschools.net/