Intracranial Stereotactic Radiosurgery (SRS) is a non-invasive method of delivering a single highly-focused dose of radiation to a target within the brain. This technology is being used by ROA doctors to treat malignant brain tumors (such as brain metastases and gliomas), benign brain tumors (such as acoustic neuromas, meningiomas, and pituitary adenomas), arterio-venous malformations, and functional disorders (such as trigeminal neuralgia). SRS represents an excellent alternative to surgery for many patients. This technology is one of the major advances in the field of neurosurgery and oncology allowing our doctors to cure many diseases during a single, non-invasive treatment in our department. The most common diseases treated with intracranial SRS include:
- Brain metastases
- Malignant Gliomas
- Acoustic Neuromas
- Meningiomas
- Pituitary Adenomas
- Glomus Tumors
- Arterio-venous Malformations
- Trigeminal Neuralgia
ROA has by far the longest and most extensive experience with SRS in Northern Virginia and we are proud to offer Frameless SRS for selected patients. There are several commercially available devices that can perform SRS including Proton Beam, CyberKnife®, GammeKnife®, Trilogy®, and TomoTherapy®. This alphabet soup of technology can often be confusing to patients. Here is a brief summary describing these applications:
Proton Beam SRS uses a different type of radiation, protons, to achieve the same treatment goal of delivering a single, highly focused dose of radiation. Therefore, the uses of Proton Bean SRS are the exact same as the other named SRS devices which, in contrast, all use x-rays to accomplish treatment. Proton Beam SRS is currently only available at a few large university cancer centers and is under active investigation. CyberKnife® and GammaKnife® are devices that use many small circular x-ray beams to treat tumors. However, because these machines can only use small circular beams their ability to treat larger and/or irregular targets is limited. In addition, while the rest of these devices can perform x-ray imaging to confirm targeting prior to SRS treatment allowing for frameless treatment, this technique is known as image-guided radiation therapy (IGRT), GammaKnife® always requires an invasive headframe. Beyond this capability, Trilogy® and TomoTherapy® can also perform computed tomography (CT) scans at the time of treatment allowing doctors to use more accurate imaging to guide the SRS treatment. Lastly, the BrainLAB™ beam shaping system is the only device made that allows doctors to use small circular beams OR larger custom-shaped beams providing the versatility to treat small round targets or large irregular targets with optimal accuracy. Based on these advantages ROA, together with Inova Fairfax Hospital, acquired the powerful Trilogy® machine as well as the BrainLAB™ beam shaping system for use in our SRS program.
The brain tumor specialists of ROA are SRS experts, having performed hundreds of cases and publishing numerous papers on SRS since 1999 when our program opened. ROA is the first in Northern Virginia to offer Frameless SRS and the only group in the DC Metropolitan area with the state-of-the art BrainLAB™ system. Together with Inova Fairfax Hospital and our neurosurgical partners we have created a World Class SRS program and are proud to offer the highest quality medical care in the area.
Typical SRS Procedure
Step 1: Consultation
After a comprehensive consultation with one of our radiation oncologists that specializes in SRS, the appropriate imaging studies will be ordered to best visualize the tumor. Typically this is an MRI that is performed with a special SRS protocol. Overall patient management and imaging studies are generally reviewed at our many multidisciplinary tumor boards where input is obtained from staff radiologists, pathologists, surgeons, and medical oncologists.
Step 2: Stereotactic Headframe placement
Under the guidance of the neurosurgeon and radiation oncologist, the stereotactic headframe will be placed on the head during the morning of the procedure. This headframe holds the skull in the same position for the duration of the treatment using four pins, the size of a pen tip, that are placed on the scalp to keep the headframe immobilized. This procedure is performed under local anesthesia and should be relatively pain-free. For selected patients we now have a Frameless SRS option where image guidance at the time of treatment is used to confirm skull positioning rather than utilizing the Stereotactic Headframe for this purpose. Your ROA doctor will discuss with you which method of immobilization is best for your treatment.
Step 3: CT scan
Once the Stereotactic Headframe or relocatable plastic headframe (for Frameless SRS) has been placed, a CT scan of the brain will be performed in the department of radiation oncology. This scan allows a precise visualization of the tumor in relationship to the 3-D reference system that has been created using a stereotactic attachment. If an MRI was previously performed to optimally define the target volume, it is then fused to these CT images by the BrainLAB™ treatment planning system. This fusion technology allows precise anatomical visualization of the tumor.
Step 4: The Treatment
Within the next several hours, a comprehensive treatment plan will be formed by the radiation oncologist, SRS physicist, and neurosurgeon. The patient will then be brought into the Trilogy® treatment room and positioned on the treatment machine. The Stereotactic Headframe or relocatable plastic headframe (for Frameless SRS) is locked into its position on the treatment couch, allowing both immobilization and localization of the tumor. The treatment is then delivered under constant monitoring by our staff.
Step 5: Discharge
Upon completing the treatment, the Stereotactic Headframe or relocatable plastic headframe is removed by the radiation oncologist. The patient is then discharged to home. SRS does not require an overnight hospital admission. The treatment is also painless. The entire procedure is performed in a single day and there is no recovery time.
Intracranial Stereotactic Radiosurgery Publications by ROA Doctors
1. Bajaj GK, Kleinberg L, Terezakis Z. Current concepts and controversies in the treatment of parenchymal brain metastases: improved outcomes with aggressive management. Cancer Investigation. 23(3): 363-376, 2005.
Extracranial Stereotactic Radiation Therapy
Extracranial Stereotactic Radiation Therapy, also known as Stereotactic Body Radiotherapy (SBRT), is a non-invasive method of delivering highly-focused radiation to a target within the body. This technology is being used in our practice to treat numerous conditions throughout the body that were previously unapproachable with conventional radiation or surgery. SBRT represents an excellent alternative to surgery for many patients who cannot undergo surgery or who prefer not to have surgery. This technology is one of the major advances in the field of surgery and oncology allowing our doctors to cure many diseases during a few, non-invasive treatments in our department. The most common diseases treated with SBRT include:
- Inoperable Lung Tumors
- Lung Metastases
- Liver Tumors and Liver Metastases
- Pancreatic Tumors
- Adrenal Metastases
- Kidney Tumors
- Brain Tumors and Brain Metastases
ROA has by far the longest and most extensive experience with SBRT in Northern Virginia. There are several commercially available devices that can perform SBRT, including Novalis®, CyberKnife®, Trilogy®, and TomoTherapy®. All of these devices can perform x-ray imaging to confirm targeting prior to SBRT treatment, this technique is known as image-guided radiation therapy (IGRT). However, only Trilogy® and TomoTherapy® can also perform computed tomography (CT) scans allowing doctors to use more accurate imaging to guide treatment and avoiding the need for surgically implanted marker seeds that can be seen with x-rays, as are needed with CyberKnife®. Based on these advantages ROA, together with Inova Fairfax Hospital, acquired both Trilogy® and TomoTherapy® for use in SBRT.
One additional obstacle in treating tumors within the body is respiratory motion. To deliver an accurate, focused treatment this must be accounted for in the treatment planning and delivery. ROA uses the most advanced equipment available to map the respiratory cycle during the target definition process. Once respiratory motion is taken into account, Trilogy® can perform respiratory-gating using a sophisticated system that controls the radiation beam in conjunction with the respiratory cycle. This allows ROA doctors to treat lung, liver, and pancreatic lesions with the greatest accuracy possible.
Typical SBRT Procedure
Step 1. Consultation
After a comprehensive consultation with one of our radiation oncologists that specializes in SBRT the appropriate imaging studies will be ordered to best visualize the tumor. Overall patient management and imaging studies are generally reviewed at our many multidisciplinary tumor boards where input is obtained from staff radiologists, pathologists, surgeons, and medical oncologists.
Step 2. Imaging Acquisition for Target Definition
The patient will report to the radiation oncology department where a custom immobilization device will be fashioned to achieve reproducible positioning and to minimize respiratory motion. Once the patient is positioned appropriately a CT scan will be obtained through that will be targeted. This data acquisition creates a 3D reference system that allows the target to be localized in relationship to 3D space in reference to the immobilization device.
Step 3. Image Fusion
Once the CT data is loaded into our treatment planning system we then use fusion technology to correlate the CT data with images from an MRI, ultrasound, or PET scan to allow the most accurate visualization of the tumor.
Step 4. Treatment Planning
After the target has been carefully defined, taking into account respiratory motion, the ROA doctor will sit down with our SBRT physicist to determine the optimal beam arrangements, shapes, angles, and weightings to treat the tumor while minimizing the dose to surrounding normal tissues.
Step 5. The Treatment
On the treatment days the patient is brought into the radiation treatment room and positioned on the treatment machine in their custom immobilization device. Image guidance is then performed to confirm patient positioning and localize the target at the time of treatment. Once these steps are completed the radiation is delivered. SBRT is a painless treatment and there is no recovery time required after this procedure.