Lower Dosage CT-guided Lung Biopsy Protocol Maintains Quality, Minimizes Exposure

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Mar 25, 2012, 09:00 ET

New Imaging Parameters Rein in Incremental Radiation Dose From Potentially Life-Saving CT-guided Biopsy of Lung Nodules to Reduce Patients' Overall Exposure

SAN FRANCISCO, March 25, 2012 /PRNewswire-USNewswire/ -- New guidelines for CT-guided biopsies of lung nodules significantly reduce radiation exposure allowing individuals the benefit of the procedure, which may cut down on overall lung cancer deaths. This research is being presented at the Society of Interventional Radiology's 37th Annual Scientific Meeting in San Francisco, Calif.

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"The published early results of a trial using computed tomography to detect lung nodules demonstrated that screening with low-dose CT reduced mortality from lung cancer by 20 percent compared to screening with chest X-rays alone," said Jeremy Collins, M.D., assistant professor of radiology at Northwestern University in Chicago, Ill. "Statistically, many people who undergo screening will have nodules detected with CT and a biopsy may be recommended. We want to minimize the side effects of the biopsy procedure," he added.

The medical community evaluates the risks of radiation exposure on patients. While there is debate about the actual risk of cumulative exposure from the types of medical imaging that emit radiation, interventional radiologists are trying to curb patient dose. CT has been gaining recognition as the most effective imaging technique for lung nodules since it is more sensitive than chest X-rays and all other imaging tests.

"Lung nodules are clearly imaged using CT because of the high contrast between normal air-containing lung tissue and higher-density lung nodules. CT technologies have come a long way in offering new tools that reduce the per-procedure radiation dose," said Collins.

This research focuses on a new set of CT imaging parameters to further reduce radiation exposure while maintaining image quality. The new protocol downshifts the amount of energy the CT scanner uses to produce images and moderates the current of the X-ray tube to put out a smaller dose during examination.

"All image studies using X-ray technology are going to be associated with a small amount of finite radiation exposure," said Collins. "Although the jury is still out to some degree, there is general consensus in the community that the radiation dose risk is both linear and additive. Any place where we can reduce the incremental dose for each imaging study is very important because the overall exposure over time can be substantial," he noted.

For this study, researchers implemented the new CT imaging protocol for lung-nodule biopsy and then reviewed data from 100 people, half of whom underwent CT-guided biopsies prior to the new protocol and half after the protocol went into effect. The low dose protocol led to a dramatic 66 percent drop in radiation dose, and image quality was maintained for all of the CT-guided biopsies.

"We found that simple modifications to the CT technique used for guidance to perform lung biopsies resulted in a significant dose reduction to individuals treated," noted Collins. "This was possible while maintaining appropriate image quality for interventional radiologists performing biopsy, and fortunately the modification to the scanner technique is simple and can be applied to any existing CT scanner system," he added.

"The new protocol can be adopted immediately to reduce exposure, but interventional radiologists will still need to evaluate each person on a case-by-case basis, especially smaller people or those who have anatomy that is more difficult to image. The dose can be reduced even further for children, but more studies need to be done to tailor the protocol," says Collins.

Interventional radiologists are highly trained in radiation safety and continue to provide new data and education related to radiation physics and how radiation affects the body. The Society of Interventional Radiology is dedicated to the safety of patients as well as health care professionals and promotes minimally invasive procedures and techniques that reduce overall radiation exposure. As an organization at the forefront of radiation safety, the Society of Interventional Radiology presents the newest research for the assessment of radiation dosage, provides education to the medical community and the public about radiation protection and dose reduction, and encourages communication between doctors and their patients.

More information about the Society of Interventional Radiology, interventional radiologists and minimally invasive treatments can be found online at www.SIRweb.org.

Abstract 62: "Implementation of a Low-dose Protocol for CT-guided Lung Biopsy Procedures," J.D. Collins, P. Entezari, R.J. Lewandowski, V. Yaghmai, A. Nemcek, J.C. Carr, radiology, Northwestern University, Chicago, Ill., SIR 37th Annual Scientific Meeting, March 24–29, 2012. This abstract can be found online at www.JVIR.org.

About the Society of Interventional Radiology
Interventional radiologists are physicians who specialize in minimally invasive, targeted treatments. They offer the most in-depth knowledge of the least invasive treatments available coupled with diagnostic and clinical experience across all specialties. They use X-ray, MRI and other imaging to advance a catheter in the body, such as in an artery, to treat at the source of the disease internally. As the inventors of angioplasty and the catheter-delivered stent, which were first used in the legs to treat peripheral arterial disease, interventional radiologists pioneered minimally invasive modern medicine. Today, interventional oncology is a growing specialty area of interventional radiology. Interventional radiologists can deliver treatments for cancer directly to the tumor without significant side effects or damage to nearby normal tissue.

Many conditions that once required surgery can be treated less invasively by interventional radiologists. Interventional radiology treatments offer less risk, less pain and less recovery time compared to open surgery. Visit www.SIRweb.org.

The Society of Interventional Radiology is holding its 37th Annual Scientific Meeting March 24–29 at Moscone Center, San Francisco, Calif. The theme of the meeting is "IR Evidence," chosen to reflect interventional radiology's gathering, presenting and discussing results of care-changing investigations.

SOURCE Society of Interventional Radiology