Intensity Modulated Radiation Therapy (IMRT)
IMRT is an advanced form of 3D therapy. It uses Turville Bay’s Linear accelerator, a computer-driven machine, to actually move around the patient as it delivers radiation. IMRT involves the use of multiple high-energy x-ray beams to target the tumor. In addition to shaping the beams and aiming them at a specific area from several angles, the intensity (strength) of the beams can be adjusted to minimize the dose reaching the most sensitive normal tissues. IMRT actually varies the intensity of the radiation therapy according to the dimensions of the cancer in three dimensions. A single IMRT beam is composed of many small “beamlets”; each can be a different intensity. Very complicated cancer shapes can be created, with rapid fall-off of dose immediately outside the cancer. This allows the radiation to be more focused on the tumor cells, sparing much of the surrounding healthy tissue and leaving tumors unable to divide and spread. Prostate, brain, neck and head, breast, thyroid and lung cancers as well as gynecologic, liver, brain tumors, lymphomas and sarcoma/s are currently treated with IMRT.
The helical mode of treatment combines 360-degree fan-beam delivery of intensity-modulated radiation therapy (IMRT) and megavoltage CT (MVCT) imaging to complex tumors. During treatment delivery, the linear accelerator completes multiple 360-degree rotations around the patient while the couch passes through the center bore of the system. With helical tomotherapy the delivery angle moves across three dimensions, to produce conformal dose distributions. It enables the delivery of thousands of narrow beamlets, which are individually optimized to target the tumor. The TomoHelical mode maximizes conformality and uniformity of dose to the tumor while minimizing exposure to healthy tissue. The Turville Bay healthcare team creates a treatment plan that defines dose goals for the targeted tumor, dose constraints for structures that must be avoided, the level of modulation for the plan and the fractionation schedule.
Image Guided Radiation Therapy (IGRT)
IGRT is radiation treatment supported by enhanced graphic targeting. It is particularly useful when addressing prostate, breast, lung, spine head/neck cancers and other sites in the body. Dynamic Targeting IGRT provides the staff at Turville Bay with high-resolution, three-dimensional images to pinpoint tumor sites, adjust patient positioning when necessary, and complete a treatment—all with the patient in the position of treatment.
Simply stated IGRT technology accounts for motion, like breathing that causes tumor movement, to ensure that the targeted area is in the same position every treatment session. This technology helps us raise the quality of patient care to new levels by further reducing exposure of healthy tissues by targeting the right dose to right place at the right time. These capabilities take IMRT and stereotactic IMRT technologies one step further by raising the quality of patient care and improving efficiency.
On Board Imaging, or OBI, is an imaging technology that employs multiple methods of imaging. One of these methods makes it possible to take 3-D, 360° CT scans of a patient while he/she lies on the treatment couch. This type of imaging is known as Cone-beam CT (CBCT), a new form of CT scan. CBCT provides 3D images of the body before the delivery of treatment using less radiation than older CT scanners. CBCT is especially useful for imaging cancers of the head, neck, prostate, lung, pancreas and cervix, among others. This tool is extremely useful in making treatment more precise.
An On-Board Imager (OBI) produces both excellent quality "kilovoltage" and "Cone-Beam Computed Tomography" images in less than a minute. Tumors are located quickly and precisely at the beginning of each session, allowing treatments to be completed quickly. The ability to target the tumor and avoid the normal tissues is extremely critical in certain disease sites, and the ability to use the linear accelerator as a CT scanner allows small couch adjustments to ensure optimal positioning.
Often referred to as SRT, this therapy delivers small individual doses of radiation over multiple treatment sessions, so that the total accumulated dose is larger. It’s a precise and accurate delivery system. The overall total dose is higher than with a Stereotactic Radiosurgery treatment.
SRT treatment is sometimes called "fractionated" therapy. SRT combines the precision of Radiosurgery with fractionated radiation improving the delivery over standard radiation therapy.
A dose of radiation damages cells, specifically the cell’s DNA. Normal cells can repair this damage while tumor cells are less able to. While a tumor is precisely targeted with SRT, some healthy tissue receives a small amount of radiation, is damaged, and will begin to repair itself. Each treatment damages the abnormal tissue even more. The healthy tissue recovers, the diseased tissue does not.
Stereotactic Radiosurgery (SRS) uses Turville Bay’s computer guided radiation therapy system, directing highly focused beams of radiation into tumors and other abnormalities of the head and neck. SRS is a non-surgical method and utilizes a LINAC Scalpel, or Stereotactic linear accelerator. It delivers high doses of radiation to a specific area within the head and brain. The entire treatment dose in the Radiosurgery treatment is delivered in a single fraction directly to the area of the tumor or abnormality. Very little radiation reaches normal brain structures or tissue, and there is virtually no recovery time. Radiosurgery is ideal for treating arteriovenous malformations, acoustic neuromas, and tumors located deep within the brain.
Stereotactic Body Radiation Therapy
Also referred to as SBRT, this therapy has been developed to extend the success of Stereotactic Radiosurgery to extracranial targets. The use of tumor imaging guides radiation administration, patient immobilization, and conformal radiation therapy techniques. It’s a precise and accurate delivery system. Each SBRT treatment is called a "fraction.” SBRT combines the precision of Radiosurgery with fractionated radiation, in some cases improving the delivery over standard radiation therapy.
SBRT is the delivery of a single high dose of radiation treatment or a few fractionated radiation treatments (usually up to 5). The high potent dose of radiation is delivered to the tumor, in some instances improving the cure rates for the tumor, in a manner not achievable previously. Turville Bay’s physicians are specially trained in SBRT and able to deliver high doses of radiation, with very sharp dose gradient outside the tumor and into the surrounding normal tissue. (UCLA RADONC)
3D Conformal Radiation Therapy
3D Conformal Therapy allows us to shape the radiation beam around the tumor and control the dose of radiation throughout the process to limit exposure to normal healthy tissues.
Radiation Therapy for Palliative Care
CT Scanning for Simulation
CT Scanning is used to map the organs and structures within the body during treatment planning. CT Simulation is necessary to acquire measurements and other technical data. Structural imaging techniques using CT define gross tumor volume (GTV). CT simulators are key equipment in all well-equipped radiation oncology departments. CT images have historically provided the basic information used to define treatment volumes and, because they contain information on electron density, also form the basis for calculating three dimensional radiation dose-distribution within treatment planning computer programs.
In a conventional three-dimensional treatment planning process, the patient is placed in the treatment position and a planning CT scan is acquired. After CT data are loaded into the radiation therapy treatment planning workstation, the next step is the contouring of tumor and normal tissues. Regions of tumor or the GTV are identified and contoured by the radiation oncologist. Treatment planning is individualized for every Turville Bay patient. It may take a few days in some cases, and 2 weeks or more in very complex cases.
Radiation Treatment for Non-Cancerous/Benign Conditions
Radiation therapy for a variety of benign diseases affecting soft tissue and bone is administered at Turville Bay. The majority of benign soft tissue masses are of little clinical consequence, however some locally aggressive benign conditions including acoustic neuromas, meningiomas, and trigeminal neuralgia are treated successfully with radiation therapy. Stereotactic Radiosurgery was introduced by Turville Bay in 2004 when 4 Madison area neurologists suggested that SRS could be used to successfully treat patients with either malignant or non-malignant conditions that were considered inoperable.
Magnetic Resonance Imaging
Detailed MRI studies are sometimes employed for cancer diagnosis, staging, and treatment planning. MRI is utilized to precisely pinpoint cancerous cells within the body and can be especially useful in revealing metastases. MRI can provide greater contrast when needed between the different soft tissues of the body than a CT scan. It is especially useful for imaging the brain, spine, muscle, connective tissue, and the inside of bones. (cancer treatment centers of america)