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Internal Radiation
Brachytherapy (also called internal
radiation) is an experimental method currently being developed to use on breast cancer
patients. Instead of using radiation beams from outside the body, radioactive substances
are placed directly into the breast tissue next to the cancer. Brachytherapy involves the
surgical placement of 10 to 20 plastic catheters (tiny tubes called implants) into the breast tissue next
to the tumor to help guide the radioactive materials to the correct area of the body.
Technologists then insert pellets of radioactive substances (called Iridium-192) into the
catheters. Nine or more times over the course of a week, the catheters are briefly
connected to a high-dose-rate brachytherapy machine for internal radiation treatment. The
treatments usually take about 10 minutes each and are painless. The tubes are usually
removed after a week.
Brachytherapy is not standard practice
for breast cancer patients but is currently used on cancers in other areas of the body
such as the mouth, cervix, or prostate.
Possible advantages of brachytherapy:
- The reduction of time a patient has to
undergo radiation therapy from at least six weeks to one week.
- Less irritation of healthy breast
tissues.
- Patients who must also undergo
chemotherapy as part of their breast cancer treatment do not have to delay treatment for
as much time.
- Fewer skin reactions, such as redness,
rashes, or irritations
Physicians are unsure whether
brachytherapy is as effective in destroying breast cancer cells as external beam radiation
therapy. Several clinical trials are currently being run
to evaluate the safety and effectiveness of brachytherapy. Side effects of brachytherapy
include risk of infection and breast swelling.
Dose Verification System
The dose verification system (DVS), which is manufactured by Sicel Technologies, has been approved
by the U.S. Food and Drug Administration (FDA) for radiation treatment of breast and prostate cancer
in 2006. DVS helps radiologists determine the amount of radiation a patient receives is within the
prescribed range each time radiation treatments are administered. To do so, the radiologist can
use the system measures the amount of radiation that is delivered to the tumor tissue, tumor
bed, or healthy tissue. DVS differs from normal radiation therapy in that the physician
must implant DVS radiation dosimeters near the tumor or tumor bed and/or surrounding
normal tissue during a minimally invasive procedure. Most patients receive one or two
dosimeters. Once implanted, wireless technology transmits the information to a hand-held
monitor and radiation absorption rates are read during daily treatments, enabling
radiologists to verify that the dose received by the patient is within the
prescribed range. The dosimeter does not produce radiation itself.
The DVS implantable dosimeter is 0.8 inches (20mm) long and 0.08 inches (2.1mm) in diameter. During radiation
treatment, each dosimeter transmits the amount of radiation that is received at its location. The dosimeter
near the tumor should receive the highest dose, while the other receives a lower dose. After radiation
treatment sessions are completed, the dosimeters will remain inside the patient without an effect on
a patient's daily routine.
In January 2008, the U.S. Centers for Medicare and Medicaid created a new HCPCS code (Healthcare Common Procedure
Coding System) for the DVS. The code will cover the cost for the Dose Verification System (DVS). The code, which
reimburses radiation therapy centers for the medical device when implanted in any body site, makes DVS more
accessible to patients undergoing radiation treatment for breast and prostate cancer because private insurers
will cover the cost for the device. The cost for the device is also adequately covered by the new code for
Medicare patients treated in freestanding centers. Separate codes are available to cover the cost associated
with implanting the device.
The patient's physician will determine whether she is a candidate for DVS. Some patients have experienced
discomfort after the implantation of the DVS dosimeters; however, according to Sicel Technologies, no
adverse long-term effects have been reported.
Additional Resources and
References
Updated: June 8, 2008
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