- Proton Therapy
- Gamma Knife Radiosurgery
- Intensity Modulated Radiation Therapy
- Accelerated Partial Breast Irradiation
- CT-Driven Virtual Simulation
- Intraoperative Radiation Therapy
- Linear Accelerator/In-Room CT
- On-Board Imaging
- Proton Therapy and Chemotherapy
- Stereotactic Spine Radiotherapy
- Stereotactic Body Radiation Therapy
Proton Therapy: MD Anderson has offered proton therapy since May 2006. Patients can be treated on three different passive modulation beam lines, which treated approximately 12 hours per day. The expected benefits of proton therapy, including fewer treatment side effects, are being observed daily. MD Anderson's Proton Therapy Center is the only treatment facility of its kind in the Southwest.
Gamma Knife: The Gamma Knife is a 30-ton machine that contains a cylindrical cone made of the world's largest piece of tungsten with lead shielding. The machine has 192 Cobalt-60 radiation sources that are shaped by eight sectors that surround the patient's head.
Intensity Modulated Radiation Therapy (IMRT): A type of 3-dimensional conformal radiotherapy that focuses multiple radiation beams directly on the tumor itself. Beam intensities vary, so that the highest possible doses can be used to destroy cancerous tissue. Proper positioning of the patient is crucial to the success of IMRT. Radiation oncologists use special planning software to determine the most accurate treatment.
Brachytherapy: Using ultrasound, dozens of tiny "seeds" containing radioactive iodine (I-125) are placed at the tumor site with a special needle. The seeds release their radiation over a period of time. Brachytherapy is particularly effective for prostate cancer, destroying the tumor while sparing the urethra, bladder and other nearby organs.
CT-Driven Virtual Simulation: MD Anderson has several CT (computed tomography) scanners dedicated to simulating radiation treatments for each individual patient. These simulations are used to test various treatment fields and devices used to immobilize the patient during therapy. Data from the simulators ensures that patients get the appropriate dose of radiation before treatment begins.
Intraoperative Radiation Therapy (IORT): IORT is a special treatment option that directly irradiates a surgically exposed tumor or tumor bed. The procedure is performed within a dedicated OR suite, a special amphitheater with all state of the art surgical equipment with the addition of a special radiation treatment unit containing a high dose rate iridium (lr-192) source capable of delivering a high dose of radiation. This large-fraction dose of radiation is focused on a surgically exposed tumor or tumor bed while the surrounding healthy organs and tissues are either shielded by lead shields or displaced from the radiation field. This procedure is also known as High-dose-Rate (HDR) intraoperative radiation therapy.
HDR-IORT is also effective for tumors that might not be resectable or for which resection might be difficult, thus leaving close or positive margins. Specifically, IORT has been used to treat advanced or recurrent colorectal, gynecologic, genitourinary, pancreatic, and gastrointestinal cancers as well as primary, locally advanced cancers that have a low likelihood of cure with surgery alone.
Many tumors move with the patient's breathing, which needs to be taken into account when planning treatment. All patients treated at MD Anderson who have tumors that may move with respiration are imaged using 4DCT, a special technique that allows oncologist to take this motion into account during the planning of the radiation therapy. Some patients may benefit by techniques to control tumor motion during treatment by only turning on the treatment beam for part of the breathing cycle. This type of treatment is called gating.
Gating can be done with the patient breathing normally or while they hold their breath. For gating during normal breathing a computer monitors the patient and will only turn on the treatment beam when the patient is at a predetermined place in their breathing cycle. For gating during breath-hold the patient is given video-feedback to help them hold their breath at the correct level. A computer monitors the patient and only turns on the treatment beam at the correct level. Breath-hold gating has an added advantage of separating the tumor from nearby tissues and thus show benefits even for some patients whose tumors do not move with breathing, such as breast patients.
When radiation therapy is used to treat left-sided breast cancer patients, a primary concern is unwanted radiation to the heart, which could result in late cardiac injury. It is extremely important to protect the heart during irradiation without compromising the success of target breast and nodal irradiation. To accomplish this task we use Deep Inspiration Breath Hold (DIBH). During treatment patients' breathing patterns are continuously monitored and before turning on the radiation beam, patients are instructed to take a deep breath and fill their long to a predetermined and monitored level. This motion would cause the heart to move down and away from the left breast. When the respiratory monitor indicates the desired volume of air has been achieved in the lung, then and only then the radiation beam will be delivered. Thus, insuring a full breast target coverage while reducing cardiac toxicity.
Linear Accelerator/In-Room CT: A treatment room which contains both an accelerator and a CT unit. The same treatment table is used for both imaging and treatment, allowing for unique treatment applications, such as treating metastasis to the vertebral bodies and the comparison of various imaging techniques in their ability to locate different targets.
On-Board Imaging: The on-board imager is an automated system for image-guided radiation therapy that provides high-resolution X-ray images to pinpoint tumor sites. The on-board imager is mounted on the treatment machine via robotically controlled arms that can be positioned for the best possible view of the tumor. The image detector shows radiologists exactly how a tumor will move during treatment due to breathing or other patient movements. This technology also gives physicians the ability to incorporate a unique 150 kV X-ray tube designed for generating CT-quality images from a moving gantry.
Proton Therapy and Chemotherapy
Delivering chemotherapy and radiation together is increasingly becoming a standard treatment option for many forms of cancer. In the past, chemotherapy and radiation therapy were given one after the other, but research has shown that providing both simultaneously can be more effective at killing certain types of tumors. This “concurrent” treatment has been shown to extend survival rates for patients with cancers of the lung, esophagus, head and neck (especially the nasopharynx) and cervix.
The advantage of proton therapy over the more common X-ray-based radiation therapy is that proton radiation delivers its cancer-fighting energy more precisely, destroying the tumor with little damage to surrounding healthy tissue. This allows a higher dose of radiation directly into the tumor and spares critical structures nearby, such as the esophagus, lungs, and heart – all of which can be very sensitive to the effects of radiation. This can be especially important when chemotherapy and radiation are given concurrently, as people who undergo proton therapy typically experience fewer side effects and are better able to tolerate more than one type of treatment at a time.
To learn more about proton therapy, please visit the Proton Therapy Center.
Stereotactic Spine Radiotherapy
Stereotactic guided radiation is combined with CT guidance for the highest possible dose to spinal tumors while minimizing harmful side effects. A computed tomography (CT) machine is in the same treatment suite as the linear accelerator, so that radiation oncologists can instantly adjust radiation beams to account for any changes in tumor location, no matter how small. Patients remain immobilized on the same treatment table while the CT moves on rails around the table to confirm tumor location.
Stereotactic Body Radiation Therapy (SBRT)
SBRT combines elements of three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), which links CT scans of the tumor site with treatment-planning software to determine optimum photon radiation beam direction and intensity, and image-guided radiation therapy (IGRT) techniques that cope with tumor motion and anatomy changes during the course of radiotherapy.
SBRT allows the delivery of ablative dose of radiation to the target in significantly shortened treatment time, individual treatments, called "fractions" have been reduced from 35 to fewer than 5 in this approach, while minimizing damage to normal tissues in the tumor region. This approach has been used in patients with early stage or isolated recurrent/metastatic cancer in the lung, liver and other sites.