by David Kuehn

This article originally appeared in the November 2011 issue of DOTmed Business News

There are few industries where the quality and engineering of replacement parts is more important than that of the medical equipment industry. Among medical equipment offerings, imaging equipment systems and parts manufacturers of CT, fluoroscopy and nuclear medicine devices are under particular scrutiny. Exacting replication of system specifications is of the essence- patient safety and diagnostic accuracy and confidence center on it.

With the FDA’s recent Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging and other drivers, patient radiation dosing and safety has become a hot topic. The last two RSNAs and ECRs have hosted heavy coverage and multiple sessions on the subject. The health care media, especially radiology publications, have turned their attention to the issue of patient dosing with a focus largely on the issue of unnecessary radiation exposure above what is regarded as optimal to achieve clinical goals. Higher doses may enhance image resolution but can approach upper limits of what is considered safe, levels which are constantly questioned and reevaluated.

This has not been necessarily a bad discussion as it has created a healthy dialog among radiologists, regulators, patient safety organizations/advocates, radiation physicists, hospital administrators and manufacturers. It has also stimulated work among manufacturers to develop devices that can deliver equivalent or better resolution with lower doses. This is progress and something the industry can take credit for.

While most of the discussion has focused on excess dosage, less attention has been paid to dosage that does not achieve the desired image which could just as well be on the low side. If a dose is too low, it is likely to result in a poor image that is unusable clinically and/ or could lead to an inaccurate diagnosis. Patient dose can actually be worse if it falls below manufacturer specifications than if it rises higher. This is because a low-quality image may require additional imaging procedures to get the proper image — a true argument for quality over quantity.

Therefore, patient doses which are too high or too low can each pose clinical and radiation dilemmas. Radiologists in particular need to be reassured that imaging equipment replacement parts- especially those that emit ionizing radiation- are engineered to be precise in form, fit and function and undergo rigorous, verifiable testing. Ideally, the testing should be done by an independent, outside company.

Dunlee sponsored such an independent study which was conducted by hospital physicist Professor Robert L. Dixon, Ph.D and president of Radiological Physics Consultants, Inc. and past president of the American Association of Physicists in Medicine, to measure and evaluate the use of Dunlee tubes on GE CT systems. The objective was to determine if Dunlee X-ray tubes delivered an equivalent dose within the published GE specifications for its own CT scanners equipped with comparable X-ray tubes including both the GE VCT* and GE LightSpeed-16* scanners.

Through this methodical and statistically rigorous independent evaluation, it was determined that these replacement X-ray tubes are well-matched to that of GE in terms of the dose delivered by each to the head and body dosimetry phantoms for the standard CTDI scan techniques as published by GE in its Technical Manual.

As doctors and scientists are highly data-driven and expect verifiable evidence of any claim, replacement part manufacturers and other stakeholders should be eager to obtain independent verification of replacement part quality and technical specification matching and performance. That is particularly important where diagnostic quality and patient safety hang in the balance, such as in the replacement of CT scanner X-ray tubes that must measure up- literally- in every respect.

*indicates may be trademarked by the referenced OEM.

David Kuehn is the vice president, global marketing and sales for Dunlee Division/Philips Healthcare. He has more than 20 years of industry experience in medical imaging, with eight years in the X-ray tube sector with Siemens and Varian, leading global sales and marketing. Kuehn also spent three years with Lorad and Trex Medical Corporation as vice president of international sales for mammography, breast biopsy, cardiology and X-ray products. Kuehn graduated with a bachelor’s in marketing from Western Illinois University and an MBA from DePaul University in international business.