Infrared light probes varicose veins

17 Feb 2004

An infrared digital imaging system will be used to compare three varicose vein treatments.

A team of Dutch scientists has developed an infrared digital imaging system to study varicose veins. Using their set-up, the researchers now plan to embark on a 3 year, 600 patient trial to compare three traditional varicose vein treatments.

“Nowadays, non-invasive methods for imaging varicose veins include ultrasonic techniques such as duplex scanning,” explained Raymond de Zeeuw from Sint Franciscus Gasthuis Hosptial in Rotterdam. “We decided to find another, non-invasive and easier way to quantify varicose veins. By using this infrared technique, we hope to get an objective score for recurrence of varicose veins after treatment.”

The simple set-up uses a modified 5-megapixel digital camera and a filtered halogen lamp. Contrary to standard devices, the team’s camera does not have an infrared blocking filter over its CCD chip. The researchers filter the halogen bulb’s broadband output to remove visible wavelengths below 700 nm.

Images are then analyzed using custom-written image processing software. To evaluate the effectiveness of different treatment methods, the digital picture is divided into rectangular blocks. The software then calculates the percentage of varicose veins present in each block. Compared with alternative methods, de Zeeuw says this procedure is faster, easier to perform and gives a good overview of the affected area before and after treatment.

The team plans to put the system into practice in around 2 months time. “The primary objective of the trial is the comparison of recurrence rates of varicose veins after 2-3 years,” explained de Zeeuw.

Because the infrared light used in this study penetrates between 1 to 3 mm into the skin, the researchers add that this technique could be useful for studying other venous conditions.

Details of this project were presented by team member Herke Jan Noordmans from Utrecht's University Hospital at the Photonics West conference in San Jose, January 2004.

Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.