Brachytherapy is a form of radiation therapy (radiotherapy), which involves the placement of radioactive sources directly in a tumor or body cavity. It may be given as interstitial therapy (implanted in catheters or directly into the tissue), intracavitary therapy (placed in body cavities), or intraluminal therapy (placed in an airway or blood vessel). The sources give off a specific amount of radiation to treat the cancer. There are two basic types of brachytherapy called Low Dose Rate (LDR) and High Dose Rate (HDR). The one used is based on the needs of each patient. Brachytherapy may be used as part of a treatment plan involving external beam radiation therapy and other modalities such as surgery or chemotherapy, or it may be delivered independently as the sole treatment.
Brachytherapy treatments can be effective for various head and neck cancers. Some implants may be left in place permanently or temporarily. One type of Brachytherapy is performed by permanently implanting radioactive seeds in the cancerous tissue so they can give off their radiation dose for weeks or months and then become inert. The other type called High Dose Rate (HDR) Brachytherapy uses a highly radioactive source that is temporarily placed near the target area to quickly give a high dose and then removed.
Low Dose Rate (LDR) Radioactive Seed Implants
Radioactive seeds are sometimes placed in diseased tissue on an outpatient basis or during an operation. They may be used to keep the radiation dose focused on a specific organ or they may be placed in areas where it is difficult or impossible to assure complete surgical removal of all the diseased tissue during an operation. One type of LDR Brachytherapy is a prostate seed implant or PSI. During this intraoperative procedure, radioactive seeds are placed within the prostate gland to treat prostate cancer. This is one of the most effective options for many men whose cancer is in an early stage. Seeds are placed using ultrasound guided implantation techniques and deliver a dose of radiation to the prostate gland, with real time dose optimization, while sparing the normal surrounding tissues. These tiny seeds contain a radioactive material, such as Iodine-125, Palladium-103 or Cesium-131 and are permanently implanted in the prostate gland where they give off low-level radiation for weeks or months and then become inert.
High Dose Rate (HDR) Brachytherapy
During HDR treatments, a tiny highly radioactive source is computer guided through a catheter to the area to be treated. It is left in place for a few minutes to deliver a therapeutic dose of radiation and then removed. There is little or no discomfort. This type of HDR treatment is often given to treat cancers within the bronchial tubes of the lung, breast, prostate, head and neck. Patients, who need additional radiation but cannot get additional conventional radiation because of prior treatment, also may benefit from this type of targeted therapy.
MammoSite- Accelerated Partial Breast Irradiation (APBI) using Brachytherapy
Partial Breast Brachytherapy is a breast conserving therapy that has become a major treatment modality for Stage I and II breast carcinoma for patients who have undergone a lumpectomy. The Department of Radiation Oncology offers a partial breast treatment technique sometimes referred to as MammoSite Breast Brachytherapy. Treatment of breast cancer with Mammosite usually involves a five-day treatment course (2 times a day) with each treatment taking about 15 minutes each. After the breast cancer is removed, a small, soft balloon attached to a thin catheter is placed inside the lumpectomy cavity. The balloon is filled with saline solution and remains in place during the five-day treatment. During the twice-per-day treatments, the catheter is attached to a computer-controlled HDR Brachytherapy unit which inserts the radioactive sources according to the treatment plan. APBI is delivered directly to the cavity from which the breast cancer was removed rather than to the entire breast, which allows for a much higher daily dose compared to that used during the standard whole breast radiation therapy and often yields excellent cosmetic results. At the end of the five days, the treatment is complete and the catheter is removed.
Contura Balloon for Brachytherapy
A new procedure with regards to breast conservatory therapy is the Contura system. The Contura system differs from a typical MammoSite treatment in that the balloon contains five separate tubes within. The addition of these tubes helps your doctor shape the dose away from the skin or chest wall. The balloon also uses a vacuum to remove excess fluid and adhere closely to the lumpectomy cavity. Due to the conformity of the balloon within the lumpectomy site, the radiation is administered only where it is needed, sparing exposure to normal breast tissue. The Contura balloon is usually used in conjunction with a lumpectomy but not all lumpectomy patients are candidates for this system. Alternately, patients who do not fit the criteria for traditional MammoSite balloon-therapy may be given the option to receive treatment using the Contura system.
Intra-Beam Radiation Therapy
Intra-beam radiation therapy is a technique that delivers the radiation treatment either while the patient is in surgery or on an outpatient basis within the Radiation Oncology department, depending on the clinical indication. The Intrabeam System offers the least disruptive treatment method available to patients being treated for early stage breast cancer. Following lumpectomy, the radiation dose is aimed directly at the exposed tumor bed, while surrounding healthy tissue is moved aside. A miniature radiation source is placed within an applicator and inserted into the lumpectomy site for treatment. The entire dose of radiation that is needed will be given in one treatment, which may take from two to 30 minutes. For patients displaying local recurrences where repeated external irradiation is no longer indicated, Intrabeam may offer an alternative option for breast conserving treatment. Upon consultation, the radiation oncologist will provide the optimal treatment options to the patient based on diagnosis and pathological findings.