CyberKnife® is the world's only robotic radiosurgery system that treats tumors throughout the body non-invasively. The CyberKnife® Robotic Radiosurgery System is a non-invasive alternative to surgery for benign and malignant tumors anywhere in the body.
“CyberKnife allows us to deliver high-dose radiation to a very specific location with very high accuracy,” Dr. Foroohar explains. “It's useful for hard-to-reach tumors in the brain, as well as for cases of multiple tumors where we wouldn't want to necessarily radiate the patient's whole brain.
“We can also apply CyberKnife to many other parts of the body, including the spine,” she adds. “With CyberKnife, we we're able to treat patients with spine metastases—where cancer has spread to the spine—who would normally have received conventional external beam radiation.”
Benefits for patients include:
“The beauty of CyberKnife is that it's frameless,” Dr. Foroohar explains. “With some other systems, you have to screw a frame into the patient's skull to fixate it, and then do the imaging with that apparatus on their head.
“CyberKnife is frameless—there's no need to screw a frame into the patient's skull, so it's much more comfortable,” she says.
“Instead of an invasive frame, CyberKnife uses an Aquaplast mask that's contoured to the brain tumor patient's skull,” Dr. Foroohar explains. “With the mask on their head, the patient undergoes a CT scan. That CT gives us reference points based on the mask contoured to the patient's head.
“CyberKnife patients also undergo an MRI—without the mask—using a protocol where the images are very thinly sliced,” she adds. “Then the images from the CT and the MRI are merged or fused.
“The merged images give us a CT/MRI with a frame, without having to use an invasive frame on the patient's head,” says Dr. Foroohar. “The CyberKnife software uses those markers to know exactly where the head is to deliver precise radiation to the exact target we're going for.
“CyberKnife is image-guided radiation,” Dr. Foroohar explains. “It essentially 'paints' the tumor with radiation, precisely delivering treatment to the tumor alone while sparing the healthy tissue surrounding it.”
And CyberKnife is the only system that monitors and tracks tumor position continually during treatment.
Does every hospital offer CyberKnife?
No—very few hospitals offer CyberKnife. Northwest Community Hospital's CyberKnife Stereotactic Radiosurgery System is dedicated to treating patients with this leading-edge technology.
There are different modalities of radiosurgery, but unlike CyberKnife, they are not frameless and they can't be used for the entire body.
What is robotic radiosurgery?
Robotic radiosurgery is a non-invasive procedure that uses a computer-controlled robotic arm to deliver high-dose radiation to tumors anywhere in the body without the use of invasive frames.
How is a patient's CyberKnife treatment course planned?
Each patient's CyberKnife treatment plan involves radiation physicists and radiation therapists—it's not a one-click thing and you've got it going. We have to customize a plan to target the radiation and block out the other critical structures.
When someone gets conventional external beam radiation to the brain, the radiation oncologist may give the patient 30 to 60 Gray over a three- to six-week period, five days per week. So every day, the patient is going to come in and get two Gray (or 200 cGray) to the brain.
We can sometimes do up to 20 Gray in one CyberKnife session. Depending on what we're treating, we normally divide it up between one and three treatments (fractions) to lessen the toxic effect to the surrounding area.
If the tumor is in a critical area—close to the optic nerve or near the brainstem, we tend to divide it into three treatments. But if it's just like a typical metastasis to the brain somewhere, usually we'll do that in one treatment—like 18 Gray in one session.
Do you often recommend CyberKnife to treat spinal tumors?
Yes. For the spine, CyberKnife offers a huge advantage. If someone has cancer such as breast cancer that can spread to the spine and the patient gets general external beam radiation, there's a much higher tendency for the cancer to come back because we can't get the same high doses we're giving through CyberKnife. And with external beam radiation, you're going to get toxicity to the spinal cord and spinal nerves.
Are there cases where CyberKnife is not the treatment of choice?
Yes. If a patient has cancer in the entire spine, we can't treat the whole spine with CyberKnife. We have to be able to define the area where we're giving this highly targeted radiation. CyberKnife is appropriate if tumors are localized to one or two levels of the spine.
We also use CyberKnife for benign tumors like acoustic neuroma, pituitary tumors and meningiomas. You can use it for many different types of tumors throughout the body. CyberKnife allows us to give a higher dose to a much more specific area than we can with conventional external beam radiation.
How do the members of the CyberKnife team collaborate?
As a neurosurgeon, I always do CyberKnife in conjunction with a radiation oncologist, whom I work closely with. I never do it alone—and the radiation oncologist can't do it alone, either.
If I evaluate a patient I believe would be a good candidate for CyberKnife radiosurgery, I will discuss the case with the radiation oncologist and then present it at the weekly CyberKnife conference at Northwest Community Hospital's CyberKnife Center.
Only when it's the consensus of the conference do we treat somebody. The conference includes several neurosurgeons, radiation oncologists, oncologists and other surgeons, such as a thoracic surgeon for treating lung cancer.
Once there is agreement that the patient should proceed with CyberKnife radiosurgery, the patient will undergo the CT/MRI. Then the radiation oncologist and I will mark where we want the radiation to go and contour the tumor. We will also mark the critical structures. The planning and dosing will involve more input from the radiation oncologist and radiation physicist.