Polarized filter may reduce unnecessary cervical biopsies and surgeries

Dr. Daron G. Ferris at Georgia Health Sciences University is leading a National Cancer Institute-funded study to determine whether a polarized filter can help reduce unnecessary cervical biopsies and surgeries. Credit: Phil Jones, GHSU Photographer

The same filtered light that enables sunglasses to reduce glare may improve a physician's ability to detect early signs of cervical cancer, reducing unnecessary biopsies and surgery.

Polarized light is more focused than traditional radial light which scatters in all directions, said Dr. Daron G. Ferris, colposcopist, family medicine physician and Director of the Gynecologic Cancer Prevention Center at Georgia Health Sciences University.

When a woman gets an abnormal , it's often followed by a colposcopic exam where radial light and magnification are used to view the cervix then biopsies are performed on suspicious areas.

A National Cancer Institute-funded study is helping determine whether also taking a look through a polarized filter improves the ability to detect , enhancing efficacy while reducing needless biopsies and the discomfort and cost that may result.

"Using both types of light to examine the cervix may give us additional perspective so we can find more disease and avoid treating something that does not need it," Ferris said.

In the study of 300 women age 18 and older, Ferris is first using the standard approach, including marking suspicious areas, then taking another look with the polarized filter to see how the findings correlate before doing a biopsy. "If we use polarized light, how does that change what we can see?" he said.

The approach might be most effective in young women where normal immature cell types in the cervix are more difficult to discriminate from neoplastic cells. This extremely thin skin is an easy target for infection by , the primary cause of , Ferris said.

"If polarized light eliminates cases where it's not clear whether the area is worrisome or not, that is going to reduce the number of biopsies," Ferris said. "We want to see if it adds value." And the confusion may not end with the biopsy: sometimes biopsies also are misinterpreted, leading to unnecessary surgery.

Just as polarized glasses help fisherman see fish swimming below the water surface, polarized light, which focuses its energy in one direction, also enables physicians to better see beneath the surface of the cervix for telltale signs of trouble. In suspicious areas, blood vessels tend to be more dilated, farther apart and more randomly distributed. "We normally look at superficial blood vessels, but this takes us to a level we have not been able to see," said Ferris of the ability to see 1 millimeter (.04 inches) below the surface with the polarized filter.

Ferris got the idea that polarized light might enhance colposcopy from studying hundreds of images of the cervix taken for fluorescent spectroscopy, which uses a polarized filter to reduce the reflection created by fluorescent light. "I started seeing things that I had never seen before and it struck me that it might be of use in colposcopy," said Ferris, who was part of a study trying to teach computers to recognize cervical lesions.

Dermatologists have been using polarized filters for years to look at external skin surfaces. Some colposcopy machines, where the cervix is viewed through a monitor rather than a microscope, already are equipped with a filter to reduce glare. Most colposcopes now have green filters that block red light so blood vessels appear black and are easier to detect.

Studies have questioned colposcopy's accuracy. Two researchers concluded in a 2006 article in the American Journal of Obstetrics and Gynecology that colposcopy was missing cancerous lesions and efforts to improve accuracy were needed.

The bagel-shaped cervix is the door to the uterus, which produces mucus and helps keep a fetus in the womb during pregnancy. Biopsies of the thin-skinned organ can result in bleeding and increase infection risk.

Related Stories

New HPV vaccine under study

Nov 19, 2007

A new vaccine against nine of the most harmful strains of human papillomavirus is under study at the Medical College of Georgia.

Study: Squid are masters of disguise

Sep 25, 2006

U.S. marine scientists say squid are masters of disguise, using their pigmented skin cells to camouflage themselves nearly instantaneously from predators.

Student Develops First Polarized LED

Mar 03, 2008

In recent years, light emitting diodes (LEDs) have begun to change the way we see the world. Now, a Rensselaer Polytechnic Institute student has developed a new type of LED that could allow for their widespread ...

Beetles stand out using Avatar tech

Apr 14, 2010

(PhysOrg.com) -- A new study suggests that jewel scarab beetles find each other -- and hide from their enemies -- using the same technology that creates the 3D effects for the blockbuster movie Avatar.

Recommended for you

Cold cash just keeps washing in from ALS challenge

Aug 28, 2014

In the couple of hours it took an official from the ALS Association to return a reporter's call for comment, the group's ubiquitous "ice bucket challenge" had brought in a few million more dollars.

Medtronic spends $350M on another European deal

Aug 27, 2014

U.S. medical device maker Medtronic is building stronger ties to Europe, a couple months after announcing a $42.9 billion acquisition that involves moving its main executive offices across the Atlantic, where it can get a ...

Mind over matter for people with disabilities

Aug 26, 2014

People with serious physical disabilities are unable to do the everyday things that most of us take for granted despite having the will – and the brainpower – to do so. This is changing thanks to European ...

Ukraine's former world's tallest man dies

Aug 25, 2014

Ukraine's tallest man, who briefly held the world record but gave it up to live as a recluse, has died due to complications from the condition that saw him never stop growing, local media reported Monday.

User comments