John Stoddard Cancer Center
1221 Pleasant Street, A-100
Des Moines, Iowa 50309
TrueBeam STx Frequently Asked Questions
What is the TrueBeamTM STx system?
TrueBeam STx is an advanced radiosurgery system from Varian Medical Systems. It was engineered from its inception to perform noninvasive, image-guided radiosurgery procedures with pinpoint accuracy and precision. It works by choreographing highly sophisticated imaging, treatment delivery and motion management technologies making it possible to deliver treatments more quickly while compensating for tumor motion. This opens the door to new possibilities for the treatment of challenging cancers throughout the body including those in the brain, spine, lung, liver, pancreas and prostate.
What is radiosurgery and how does it work?
Radiosurgery is an effective treatment for many different types of cancer. It uses sophisticated technology to deliver very precise and accurate beams of radiation to a tumor while minimizing exposure to nearby healthy tissue. There are two main types of radiosurgery-stereotactic radiosurgery (called SRS), which is for cancers in the brain and spinal region, and stereotactic body radiotherapy (also called SBRT), for cancers in other parts of the body. Both of these treatments are noninvasive-that is, the body isn't operated on in the traditional sense.
What is a TrueBeam STx treatment?
A doctor may prescribe treatment with TrueBeam STx for many reasons. This technology gives medical professionals the tools to treat many different types of cancers and other medical conditions.
TrueBeam STx is fast, with most treatments taking just a few minutes a day. A TrueBeam STx system can deliver treatments 2.4 to 4 times faster with a dose delivery rate of up to 2,400 monitor units per minute-double the output of most other radiosurgery systems. A radiosurgery treatment that typically takes 30 to 60 minutes can be completed in just 5 to 20 minutes. In addition to enabling for a more comfortable experience, as the patient spends less time on the treatment couch, faster treatments also allow for reduced chance of patient and tumor movement during treatment.
The precision of the TrueBeam STx system is measured in increments of less than a millimeter. This accuracy is made possible by the system's sophisticated architecture, which choreographs imaging, patient positioning, motion management, beam shaping and dose delivery, performing quality checks every ten milliseconds throughout the entire treatment.
TrueBeam imaging technology can produce the three-dimensional images used to fine-tune tumor targeting in 60% less time than previous Varian imaging technology. Additional functionality makes it possible to create images using 25% less X-ray dose.
For lung and other tumors subject to respiratory motion, TrueBeam STx offers Gated RapidArc® radiotherapy, which makes it possible to monitor the patient's breathing and compensates for movement of the tumor while the dose is being delivered in a continuous rotation of the treatment machine.
In addition to its impressive technical specifications, TrueBeam STx has also been designed to address patient comfort. It operates quietly and has built-in music capabilities so the patient can listen to music during their treatment. The therapist who operates the system can be in constant two-way communication with the patient. Plus the therapist can visually see the patient through three closed-circuit monitors.
What kind of radiation does TrueBeam STx use?
The treatment beam is generated by a machine called a medical linear accelerator. This machine shapes beams of energy with varying intensities generated by the machine. The treatment beam can be aimed at a tumor from multiple angles to hit the target in a complete three-dimensional manner. In fact, TrueBeam STx's treatment beam can be delivered with submillimeter accuracy and varying intensity. The idea is to deliver the lowest dose possible to the surrounding healthy tissue, while still delivering the maximum dose to the tumor.
Does radiosurgery expose people to radioactive substances?
Many people, when they hear the word "radiation," think immediately of radioactive substances. However, no radioactive substances are involved in the creation of the beam by a medical linear accelerator. When a linear accelerator is switched "on," radiation is produced and aimed directly at cancer cells. Then, like a flashlight, when the system is switched off, radiation is no longer emitted by the system.
What happens when a person is treated with radiosurgery?
Radiosurgery treatment, including TrueBeam STx treatment, involves three basic steps: visualization of the tumor, the planning of the individual treatment and the delivery of the treatment.
After their diagnosis, the medical physicist generates three-dimensional diagnostic images (usually CT or MRI) of the tumor and the area around it. They then use these images to specify the dose of radiation needed to treat the tumor. A radiation oncologist will work with a physicist to plan an individualized treatment. After this, individualized TrueBeam STx treatments can be delivered according to a schedule specific to the treatment plan.
During a TrueBeam STx treatment, the linear accelerator can rotate around the patient to deliver the radiation. The radiation is shaped and reshaped as it is delivered from many different angles. Most treatments usually take only a few minutes a day.
X-rays and/or CT scans may be taken in preparation for planning the treatment. Following these scans, the treatment planning process can take several days. When the treatment plan is complete, TrueBeam STx radiosurgery treatments can begin.
Most cases require a treatment preparation session. Specially molded devices that help the patient maintain the same position every day are sometimes developed at this point. The patient's radiation oncologist may request to have the treatment area marked on their skin to assist in aligning the equipment with the target area.
The first TrueBeam STx treatment session may sometimes be longer than subsequent ones so that additional images can be acquired to check the positioning of the tumor on the day of the treatment. This is at the discretion of the treatment team.
In the treatment room, the medical team uses the marks on the patient's skin to locate the treatment area. Then the patient is positioned on a treatment table. Sometimes, specially molded devices are used to help the patient stay still and provide correct positioning.
The radiation therapist can also use the machine's imaging technology to position the patient for a treatment that is accurate to less than a millimeter. This involves the use of high-resolution X-rays of the targeted area to verify positioning of the tumor before administering the treatment.
The radiation therapist then leaves the treatment room before the machine is turned on. The machine rotates around the patient to deliver the radiation beams, which are shaped by a special attachment called a high-definition (HD) multileaf collimator. This HD device has 120 computer-controlled mechanical "leaves" or "fingers" that can move to create apertures of different shapes and sizes.
Who are the professionals a patient may typically encounter?
1) Theradiation oncologist is a doctor who has had special training in using radiation to treat diseases and prescribes the type and amount of treatment. The radiation oncologist may work closely with other doctors and the rest of the healthcare team.
2) A medical physicist participates in the planning process and ensures that the machines deliver the right dose of radiation.
3) A dosimetrist plans the treatment with the oncologist and the physicist.
4) A radiation therapy nurse provides nursing care and may help the patient learn about treatment or how to manage any side effects.
5) A radiation therapist positions the patient for treatment and operates the equipment that delivers the radiation.
How long is a course of treatment on a TrueBeam STx system?
The delivery of a patient's treatments varies depending on the diagnosis, so ask the medical professional for information about their specific diagnosis. Generally, radiosurgery is completed in just one to five treatment sessions over a week or two.
Does a person become radioactive after treatment?
External radiosurgery does not cause anyone's body to become radioactive. A patient need not avoid being with other people because of treatment. Even hugging, kissing, or having sexual relations with others poses no risk to them of radiation exposure.
Side effects of radiosurgery most often are related to the area that is being treated. A patient should consult with their medical professional to discuss the specific diagnosis, prognosis and possible side effects from treatment.
What is unique about radiosurgery using Varian's TrueBeam STx system?
The main advantages of Varian's TrueBeam STx are ease, precision and speed. Thanks to its unprecedented accuracy, the TrueBeam STx system can be used to treat some tumors in sensitive areas such as the brain, spine, lung, liver, pancreas and prostate.
Treatments focus powerful radiation on the tumor while minimizing exposure of surrounding healthy tissues. TrueBeam STx was designed from its inception to seamlessly integrate sophisticated imaging and radiation delivery systems. What this means for patients is accuracy, speed and comfort. What it means for medical professionals is the ability to treat many different types of complex conditions.
The TrueBeam STx system may not be appropriate for all cancers. Patients should ask their doctor if TrueBeam STx is right for their particular case.