Clincal Services - Brachytherapy
The Comprehensive Cancer Center at Wake Forest University Baptist Medical Center recently opened an Integrated Brachytherapy Unit (IBU) – one of only five such units in North America.
The IBU concept integrates all aspects of brachtherapy (radiation source in contact with the tumor) treatment. Patient preparation, applicator insertion, imaging, treatment planning, delivery and verification are now all possible in a single, shielded room - offering real-time savings while implant quality is improved.
The integrated procedure with the IBU ensures a stable conformal geometry for the complete process and drastically reduces the overall treatment time for each patient. So, not only is there better and more control over the entire procedure, but the patient throughput is improved dramatically.
Features:
- Rotating system enables unobstructed X-ray imaging from all possible directions without moving the patient. This is particularly important for patients with lung and esophageal cancers who cannot lay flat of their back.
- Selection of different viewing angles improves reconstruction and treatment planning accuracy.
- Image data, position and angles of rotation are digitally transferred straight into PLATO treatment planning software for 3-D reconstruction purposes, which could eliminate any manual reconstruction errors.
- Fully counterbalances L- and C- arms Motorized Treatment table, including X, Y, Z directions for a complete 3-D view.
- Quick synchronization with PLATO for up to date dose distribution.
Benefits:
- Fluoroscopy from all directions.
- Improves planning accuracy.
- Reduced risk of applicator displacement.
- Verification of source position at any time.
- More comfort for patient.
- Better use of hospital floor space.
- Intra operative brachytherapy.
- Time-saving.
- Improved implant quality.
The Integrated Brachytherapy Unit uses High Dose Rate Brachytherapy (HDR). The HDR system uses a single, tiny (1 mm x 3 mm) highly radioactive source of Iridium- 192 that is laser welded to the end of a thin, flexible stainless steel cable.
The source is housed in a device called an afterloader. The computer-guided afterloader directs the source into the treatment catheters or applicator that has been placed in the patient by the brachtherapy radiation oncologist.
The source travels through each catheter in 5 mm steps, called “dwell” position. The distribution of radiation and dose is determined by the dwell positions the source stops at and the length of time it dwells there. This ability to vary the dwell times is like having an unlimited choice of source strengths. This level of dose control is possible only with HDR.
The major advantage of HDR is that the final doses are known before any radiation treatment is given. Because the patient and implant position is the same as when the treatment plan was devised, the doses are accurate.
Because of the high radioactivity of the Iridium-192 source, the treatment time is minutes, so there is little opportunity for the implant to move and deposit radiation doses where it wasn’t intended. HDR dose accuracy is measured in millimeters.
The afterloader controls the radiation source, so radiation exposure to physicians, hospital staff and family members is eliminated. After the HDR treatment, the source retracts into the afterloader. The patient is no longer radioactive, which is why HDR brachytherapy implants are called temporary implants.
HDR brachytherapy treatment courses can be from one to 10 treatments, depending on the type of cancer being treated. There are many factors that the physician considers in determining the radiation dose, and how many treatments an implant should receive.
Currently at Wake Forest Baptist, HDR brachtherapy is used for treatment of various cancers, including prostate, breast, lung, cervical and nasopharynx.