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E M E RG I N G T E C H N O L O G I E S
I N N O VAT I O N S I N B R A C H Y T H E R A P Y
TREATING CANCER FROM THE INSIDE OUT
Brachytherapy isn't new. It has been a mainstay in the treatment of bronchial and cervical cancer for many years. Several new developments are making this treatment easier and expanding its use.
Brachytherapy treats cancer using precisely placed radioactive implants in tumors. The implants can be permanent or temporary, but the goal is the same: Conform the radiation dose to the size and shape of the target and limit side effects by sparing the surrounding healthy anatomy. "Brachytherapy has been highly successful in prostate, gynecological, breast, and several other types of cancer," said David Hall, marketing manager for Varian Medical Systems' BrachyTherapy business unit.
BREAKTHROUGHS FOR PERMANENT "SEEDS"
Varian's VariSeedTM software for intra-operative treatment planning offers real-time dosimetry for more precise placement of prostate seed implants.
Today, approximately 900 radiation oncology centers around the world use Varian's VariSeedTM treatment planning software for guiding the placement of permanent prostate seed implants in what is called low-dose-rate (LDR) brachytherapy. Use of this technique alone or with external beam radiotherapy is increasing for patients, including about 60,000, or one third, of U.S. men who are diagnosed annually with prostate cancer. Physicians want to be certain they are delivering the intended dose. Varian's recent addition of dynamic dosimetry to its VariSeed software makes that easier. With dynamic dosimetry, VariSeed maps out dose distributions as seeds are placed, allowing physicians to make adjustments as they work. During the procedure, the medical team uses ultrasound imaging with Varian's new TwisterTM 3-D data acquisition software to see the prostate and the seeds in three dimensions. "These are breakthrough advances that will increase physicians' confidence in the accuracy of treatment delivery," Hall said.
ADVANCES IN TEMPORARY SEEDING
process and more comfortable for the patient during the course of therapy. Varian also has added a VitesseTM module to its BrachyVision software to streamline prostate HDR brachytherapy, turning many treatments from overnight hospital stays to outpatient procedures. With Vitesse, doctors can transfer ultrasound images generated during needle placement directly into the BrachyVision software, eliminating the need for CT scans, and making it possible to complete a treatment plan within minutes. "In some cases, the first treatment can be delivered almost immediately after the needles have been placed," Hall said. "Vitesse helps contain the cost of treatment and makes the experience better for the patient."
A N E W U S E F O R B R A C H Y T H E R A P Y: B R E A S T C O N S E R VAT I O N
High-dose-rate (HDR) brachytherapy delivers high-intensity radiation directly into tumors through fine needles that are deployed from computer-controlled afterloaders that move the radiation source on a wire within the needle according to a prescribed treatment plan. The total dose is delivered in a series of fractions, or treatment sessions. Varian supplies VariSourceTM and GammaMedTM afterloaders, as well as BrachyVisionTM treatment planning software and applicators, for this therapy. For cervical and endometrial cancers, Varian has introduced smaller titanium applicators that are both easy to see in MRI and CT scans during the placement and treatment planning
HDR brachytherapy is now also used to treat breast cancer. Today, many women with breast cancer are successfully treated with local surgery ("lumpectomy"), followed by a six-week course of daily external beam radiation to the whole breast. Despite the proven success of this approach, some women are turning to a promising alternative: accelerated partial breast radiation. Both IMRT and HDR brachytherapy are being studied as ways of delivering accelerated partial breast radiation therapy, which involves treating the area around a lumpectomy with a highly localized dose of radiation over a period of about five days. Debbie Vermeer, a radiation oncology nurse with young children, chose HDR brachytherapy for her own treatment. "HDR brachytherapy took very little time, and I was able to maintain a normal life," she said. s