DVS – Dose Verification System for Prevention of Radiation Burns

Breast Cancer Radiation Patient Safety and Treatment Effectiveness

At the Easter potluck lunch for my breast cancer support group, Sarah* was crying. It was our one-year anniversary, and we wanted to celebrate. Sarah and I stepped outside and she told me what had happened. After being diagnosed with early-stage breast cancer, she'd had a lumpectomy and radiation, then started on Aromasin. She had done everything that her oncologist recommended. But now she had been back for a mastectomy, without reconstruction, and she felt scared and depressed. Sarah didn't need a mastectomy for breast cancer – but she needed it because of a bad reaction to the radiation treatments. Her breast skin and fatty tissue were unintentionally burned, and since her fatty tissue had died, it was hard and painful. The solution to her problem was to remove the breast that she'd tried to save. Her radiation dose had been too high.

Risk Versus Benefit of Breast Radiation
Sarah's case is extreme, but concern about the proper radiation dose has been around as long as there have been radiation treatments. Radiation to the breast is meant to give the maximum dose to a tumor, or tumor bed, while doing the least harm to your healthy tissue. You and the radiation beam must be in the right position during each treatment for the best results. But if radiation is accidentally aimed at healthy tissue, or if the dose is significantly higher than you need, it can affect your quality of life as well as your chances of long-term survival after completing treatment.

Getting the Right Radiation Dose
A new device has been approved by the U.S. Food & Drug Administration to measure the amount of radiation that is delivered to your tumor tissue, tumor bed (where the tumor was) and nearby healthy tissue. Called the DVS® (Dose Verification System), it is a tiny dosimeter that can be implanted close to your tumor area and in your adjacent healthy tissue. The dosimeter does not produce radiation, but it helps your radiology team take a very accurate measurement of the actual dose that your tissue received. This information is critical to the effective and safe treatment of your breast tissue.

Working Alongside Standard Breast Radiation
External beam radiation for breast cancer is done 5 to 7 times a week for six to eight weeks. If you have an implanted dosimeter, your radiology team can use the Dose Verification System to check the dose that is delivered during each treatment. Before and after each treatment, your technician will use a hand-held wand above your breast skin, near the dosimeter. The dosimeter uses wireless technology to transmit the dosage information to the wand, which in turn sends your radiation dose to the DVS Base Station. Your daily dose is stored in a database, where your radiologist can see the daily and cumulative doses. This information enables your doctor to verify that the dose you receive is safe and effective.

DVS Tracks Your Radiation Dose
If your radiologist recommends the DVS for you, you will have one or two dosimeters implanted in your breast. One will be near your tumor, and the other will be located nearby. Each dosimeter transmits the amount of radiation that is received at its location. The dosimeter near your tumor should receive the highest dose, while the other should be getting a lower dose. A DVS dosimeter must be implanted at least 3cm inside your breast, for the most precise readings.

Tiny Dosimeter Is Safe
The DVS implantable dosimeter is 0.8 inches (20mm) long and 0.08 inches (2.1mm) across. It is sealed within biocompatible glass, and is designed to remain in your body permanently. Your dosimeter won't interfere with electronic equipment (such as cell phones) and will not set off airport metal detectors. You may be able to feel a dosimeter when you do your monthly breast self-exam (BSE), so be sure you note its location. The DVS dosimeter is a durable device, and will not break during a regular mammogram, and has not been known to break due to a blow or trauma to the breast. This device does contain metal, but it is so small that an MRI magnet will not affect it.

Getting Help With the Cost of DVS
Medicare and most private health insurance will cover the cost for the Dose Verification System (DVS). The HCPCS code (Healthcare Common Procedure Coding System) for the DVS became effective on January 1, 2008. This new code allows for radiation therapy centers to be reimbursed for the cost of the Dose Verification System (DVS).

Take-Home Message
The Dose Verification System (DVS) benefits you by making sure that you get a reduced radiation dose to your healthy tissue (preventing skin and fatty tissue burns) and the maximum dose to your tumor or tumor site. The implanted dosimeter is tiny, safe, and won't interfere with daily activities. Most insurance carriers will help defray the costs.

*Sarah is not her real name, it has been changed to protect her privacy.

_{Sources:
Beyer GP, Mann GG, Pursley JA, Espenhahn ET, Fraisse C, Godfrey DJ, Olham M, Carrea TB, Bolick N, and Scarantino SW. An Implantable MOSFET Dosimeter for the Measurement of the Radiation Dose in Tissue during Cancer Therapy. IEEE Sensors Journal. Jan 2008. Vol 8, No 1, pp 38-51.}

U. S. FDA. 501(K) Summary for Sicel DVS Dose Verification System K052118, K061051, and K071399. PDF file format document.