Trilogy™ Stereotactic System
St. John Health System doctors are among the first in Michigan using a non-invasive, ultra-precise machine that employs a variety of treatment technologies to treat cancerous and other dangerous tumors anywhere in the body.
The one-of-a-kind device, located at Providence Park Hospital in Novi, is known as the Trilogy. It destroys deadly tumors by delivering precisely focused, high-energy radiation to a localized area in a single treatment session. Depending on patient need, doctors can treat tumors using standard radiation, intensity modulated radiation therapy (IMRT), or with stereotactic radiosurgery. The Trilogy is the only device of its kind capable of using this trio of treatments.
“This is the most versatile tumor treatment device available to patients,” says Bill McLaughlin, M.D., director of radiation oncology at Providence Hospital. “This makes it possible for us to deliver a variety of treatment options using a single machine to treat tumors in the head, neck, spine, lung, liver, prostate and pancreas.”
The Trilogy™ Stereotactic System from Varian Medical Systems is the most advanced, sophisticated machine of its type in the world.
As the leading image-guided radiotherapy (IGRT) system, Trilogy marks the beginning of a new generation of cancer care. The versatile Trilogy system combines imaging and treatment technologies, and can be used to deliver the widest range of external beam radiotherapies: 3D conformal radiotherapy, IMRT, stereotactic radiosurgery, fractionated stereotactic radiation therapy and intensity-modulated radiosurgery for cancer and neurosurgical treatments.
Advanced imaging capabilities built into the system allow therapists to position patients for treatment with submillimeter accuracy. A respiratory gating system compensates for any tumor movement that occurs as a patient breathes.
The Trilogy system is powerful, and it can deliver radiotherapy doses at least 60 percent faster than conventional accelerators. This shortens the length of time patients need to spend undergoing treatment. In addition, the radiation beam is highly precise, allowing clinicians to deliver treatments with unprecedented accuracy.
The Trilogy system is built around an advanced medical linear accelerator, a machine that rotates 360 degrees around the patient to deliver radiotherapy treatments from many angles. The Trilogy accelerator has been enhanced for stereotactic applications that involve delivering higher doses of radiation to smaller areas over a shorter period of time.
The Trilogy system incorporates sophisticated technologies for shaping the radiation beam so that the dose of radiation is limited to the region of abnormality. By changing the beam shape over time while delivering the radiation, doctors achieve very fine control over how, and where, the radiation is administered.
The Trilogy Stereotactic System also incorporates a number of technologies for positioning patients accurately, including:
- A special X-ray imager that is used to check the patient's position prior to treatment and to monitor the position of the targeted area during treatment.
- An optical guidance system with infrared cameras that continuously monitor the patient's position to provide therapists with real-time feedback about any changes in a patient's position.
- A "respiratory gating" technology that coordinates treatment with respiration, to compensate for tumor motion due to the patient's breathing.
The Trilogy system provides the following patient benefits:
- Through more precise targeting of the beam, radiotherapy can be more effective at treating disease while simultaneously reducing side effects of the treatment.
- Due to the increased accuracy and power, smaller lesions can be treated more quickly, easily and effectively.
- Radiotherapy can be used to treat more different types of cancer, which means that more patients can be spared the invasive techniques of surgery.
Stereotactic radiosurgery (SRS) is an advance in the treatment of cancer, vascular abnormalities, and certain types of pain and movement disorders. SRS painlessly shrinks or eliminates tumors and abnormalities, using focused beams of radiation. It enables doctors to deliver higher doses of radiation more precisely and in fewer treatment sessions than ever before possible.
Though it's called radiosurgery, the procedure does not involve any incisions. Recovery and healing are fast, and the patient can resume normal activities shortly after treatment.
Stereotactic radiosurgery, or SRS, is the most precise method of administering a dose of radiation to an area inside the body, in order to eliminate a tumor or other abnormality. It has been used for some time by neurosurgeons to treat vascular abnormalities and tumors in the brain, both benign and malignant. SRS's ultra-high precision destroys tumors with high doses of radiation, while sparing the surrounding healthy tissue. In this way SRS provides a noninvasive alternative to surgery, allowing treatment of some otherwise inoperable tumors.
Recent advances in imaging, patient positioning, and targeting have all made SRS appropriate for the treatment of some cancers in other parts of the body as well. Diagnostic images taken before treatment—including computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI)—help determine where to aim the radiation. The beams are shaped to match the contours of the tumor and are delivered from many different angles around the body, all converging precisely at the planned target location.
Unlike other forms of radiation therapy that might be delivered over a period of weeks, SRS treatments are usually completed in a single day. (Another treatment method, stereotactic radiotherapy, or SRT, involves just a few treatment sessions.) SRS is most often delivered as an outpatient procedure.
SRS treatment: With SRS, the full radiation dose is delivered in one session. Most patients can be treated as outpatients, and can return home immediately after the procedure. SRS is most often used to treat tumors or abnormalities in the brain and spine, although with new image-guidance techniques and corrections for respiratory motion during treatment, SRS is starting to be used more widely for treatments in other regions of the body.
SRT treatment: SRT is very similar to SRS, but instead of being completed in a single session, the dose of radiation dose is delivered over a course of several treatment sessions, instead of all at once. SRT is also known as fractionated radiosurgery, because a fraction of the total radiation dose is delivered at each session. SRT is used to treat tumors or abnormalities in the brain, head, neck, and spine. It may also be used to treat tumors or abnormalities in other parts of the body—in the lungs, liver, kidneys, and pancreas, for example.
Whether to use SRS, SRT, or some other form of treatment is a decision your doctor will make based on many factors, such as the size, location, and type of tumor, as well as your overall state of health.
Stereotactic radiosurgery requires certain key tools and technologies, such as specialized treatment planning software, a source of high-energy radiation (medical linear accelerator), devices to shape the radiation beams, and quality assurance tools, such as an X-ray imager, which is used to check your position relative to the radiation beam before treatment begins.
Software: Sophisticated computer software and three-dimensional images of your lesion and surrounding anatomy indicate the optimal way of treating your condition. The resulting treatment plan—unique to you—specifies the number of radiation beams as well as the angles required to precisely deliver the radiation dose prescribed by your doctor without harming surrounding healthy tissue.
Medical linear accelerator: A specially equipped linear accelerator is used to generate the radiation beams for your treatment. It is optimized to deliver high radiation doses to very small targets with extreme precision. It generates a radiation beam shaped to limit the dose to the region of abnormality. To do this it employs one of two devices.
Beam-shaping devices: One device – for addressing relatively small tumors or abnormalities – is a cylindrical metal block called a cone. Cones have holes of various sizes down the middle. The size and shape of your abnormality determines the correct hole size. A second device—for addressing larger tumors or abnormalities—is called a multileaf collimator, or MLC. The MLC has 120 computer-controlled tungsten metal fingers, or leaves, that can be individually adjusted to create an aperture of almost any shape. The radiation beam is passed through this aperture, and shaped by it. This ability to change the beam shape over time gives the doctors very fine control over how, and where, the radiation dose is administered.
X-ray imager: With the radiation beam shaped so exactly, care must be taken to ensure that it is aimed at the targeted area with great precision. A special X-ray imager, mounted on the linear accelerator, is used to check your position relative to the radiation beam before treatment begins. Adjustments can be made to the position of the treatment couch, if required, so that you are positioned for treatment with submillimeter accuracy.
Stereotactic radiosurgery is a carefully controlled process that consists of a series of steps: consultation, positioning, imaging, treatment planning, treatment delivery, and follow-up care.
Consultation: Your initial visit will be with the physician leading your treatment team. This may be a radiation oncologist or a neurosurgeon. The physician will review your medical history and reports, make a recommendation about any further tests that may be required, discuss the options available to you, and work with you to choose an optimal course of treatment. If it is SRS, the entire treatment process will be completed in one day; if it is SRT, you will be scheduled for a series of appointments.
Positioning: In order to achieve the precision of a stereotactic treatment, it's important to be accurately positioned and carefully immobilized during treatment. The doctor will fit you with an immobilization device to ensure that you remain in the same position – as comfortable as possible – without moving during the procedure.
There are different methods for positioning and immobilization, depending on the area to be treated. Some single-session treatments to the brain require a minimally invasive headframe. The frame is fixed to the head using pins or screws, which are put in place under local anesthetic. The frame is then attached to the treatment couch.
A frameless system may be used in other instances, especially for SRT treatments delivered over several days. Frameless systems range from a lightweight mesh mask, individually formed to fit to your face and head, to a bite block. With the bite-block system, a bite tray similar to a dental mold is closely fitted to your upper jaw and then secured to the treatment couch.
For stereotactic treatments to regions of the body other than the head, various types of body frames or cushioning systems are available for patient positioning. Your physician will discuss with you the various options to determine which will work best, given your specific circumstances.
If you have been fitted with a headframe for SRS, you will need to remain at the clinic for the entire treatment process. With other types of positioning systems, you may have the option of going home after imaging, then returning for actual treatment on another day.
Imaging: A CT scan is performed, to generate images of the area to be treated. This scan—along with any other CT, PET, MRI, and X-ray images you may have had—provides information required not only to create a treatment plan but to ensure that you are positioned correctly at the time of treatment.
Treatment planning: With the information gathered during the positioning and imaging steps, a dedicated medical team will design the best treatment plan for your situation. They will use a sophisticated software program to generate a customized plan for your treatment.
Treatment delivery: SRS treatments usually take about an hour. In some cases the treatment time can be longer. Most of the time is used to ensure that you are accurately positioned for your treatment. You may see laser lights in the room; these help the therapist make sure you are level and straight on the treatment couch. You may see and hear the robotic arms of the imager as they extend from the linear accelerator and move into position. Usually, two or more images are taken from different angles, or a complete rotation of the accelerator may be used to generate a three-dimensional image. The therapist will use these images to guide adjustment of the treatment couch. You may also notice a camera on the ceiling; this is part of an optical guidance system that monitors and corrects for any movement during the treatment. In some cases, a camera may also be used to monitor your breathing.
You will be alone in the room during the treatment, but the therapist can see and hear you at all times through intercom and closed circuit television systems. The therapist will control the accelerator, imagers, and treatment table from outside the room.
The linear accelerator emits a buzz as it produces the radiation beams. Although its effect on tumors is quite dramatic, the radiation itself is invisible. You will not feel it, either, just as you do not feel chest X rays or CT scans. You may also hear the quiet whir of the beam-shaping device and see the leaves move. The accelerator will move around you to deliver beams from different angles, according to your treatment plan. Sometimes the couch will move as well. This is all normal and part of the treatment process.
Follow-up care: After you complete your treatment, your doctor will monitor your progress with a series of follow-up visits. Blood tests, diagnostic X-rays, and even additional CT and MRI scans may be requested at these appointments. These appointments are your opportunities to discuss any problems and review how to stay healthy after treatment. Ask about nutrition, exercise, and other basics for maintaining a healthy lifestyle. You can also find out about support groups for survivors of cancer or neurological conditions.
- The Trilogy Stereotactic System is the first linear accelerator that can deliver all advanced forms of external-beam radiation therapy. By allowing doctors to choose the most appropriate treatment modality for treating cancer – whether in the body or the brain – Trilogy makes it possible to provide the most appropriate therapy for a specific patient's case, rather than being limited by technology.
- With Trilogy, doctors have the option to treat small lesions using stereotactic radiosurgery, which is delivered in a single treatment; or stereotactic radiotherapy, which is delivered over a few days; as well as more traditional forms of radiotherapy.
- The Trilogy system includes technology for positioning the patient exactly, using images of the tumor and surrounding anatomy taken just prior to each treatment. The images are used to verify tumor position immediately before the radiation beam is switched on. This gives clinicians the ability to maximize the dose to the tumor, and minimize the dose to surrounding healthy tissue.
- The respiratory gating system automatically turns the beam off and on to compensate for breathing motion during treatment. This keeps the radiation beam focused on the tumor, and further protects normal healthy tissues.
- The Trilogy system and its accessories can shape a beam very precisely, with sub-millimeter accuracy. In addition to the precision of its beam, Trilogy offers the highest dose rates available, to deliver a potent punch of radiation in a short amount of time. This combination of precision and power allows Trilogy to reduce both treatment times and side effects.
June L. Chan, MD
Hospital Privileges: Providence Hospital, Providence Park Hospital
Dr. Chan is a board certified radiation oncologists with a special interest in breast cancer. Dr. Chan started her undergraduate education at McGill University in Montreal Canada where she received a bachelor's degree in Physiology. She then received her medical degree from Albany Medical College. After medical school she moved to Michigan where she completed her residency at The University of Michigan. She was chief resident in her time at U of M. She has remained affiliated with U of M as an Assistant Professor in the Department of Radiation Oncology. Dr. Chan is up to date on the newest advances in radiation therapy of the breast including partial breast irradiation. Her passion for women's health also involves gynecologic cancers. She has a special interest in brachytherapy for GYN malignancies. Dr. Chan has numerous professional affiliations with national organizations. Dr. Chan is married with three children and spends her time away from the office with her family. Her favorite pastimes are taking her children to their various sporting events like soccer, hockey, skating, and skiing.
Janice La Rouere, MD
Hospital Privileges: Providence Hospital, Providence Park Hospital
Dr. Janice LaRouere is a board certified radiation oncologist with a special interest in breast cancer. Dr. LaRouere started her medical education at the University of Michigan with a bachelor's degree in biology, stayed on to complete her medical degree, and then completed her residency at U of M in Radiation Oncology in 1988. She is pleased to continue her association with U of M as a clinical faculty member working at St. John Providence Hospitals. Dr. LaRouere has been board certified in Radiation Oncology since 1988. She has numerous professional affiliations including the American Society of Therapeutic Radiation Oncology and Michigan Society of Therapeutic Radiation Oncology. She has a special interest in breast cancer research and has been very involved in clinical trials involving partial breast irradiation, including studies involving the Mammosite applicator. Dr. LaRouere has a special interest in therapeutic radiation and minimizing the side effects of radiation. Her interests include decreasing radiation dose to the heart utilizing ABC breath hold technique. In collaboration with the University of Michigan, her department is investigating the role of IMRT in the treatment of breast cancer. She lives with her husband who is also a physician at Providence Hospital and their 3 children. One of Dr. LaRouere's favorite quotes on her outlook regarding breast cancer comes from Helen Keller: "Although the world is full of suffering, it is full also of the overcoming of it."
Patrick W. Mc Laughlin, MD
Hospital Privileges: Providence Hospital, Providence Park Hospital
Dr. Patrick W. McLaughlin is a board-certified radiation oncologist with clinical interests in brachytherapy, prostate cancer, and head and neck cancer. His research interests include: low dose radiation sensitization of malignant gliomas; vessel sparing radiation to preserve potency; IIMRT post brachy to allow optimal combination of beam and implant dose; MRI based post implant of dosimetry for the most accurate check of a seed implant. Dr. McLaughlin received his MD degree from Wayne State University, and is certified in Internal Medicine, Medical Oncology and Radiation Oncology. He completed his residency at University of Michigan Medical School, William Beaumont Hospital - Royal Oak.