The Baltimore hospital is using Varian’s radiotherapy system to deliver image-guided treatments that can be completed in as few as five sessions.
Mercy Medical Center in Baltimore is expanding its prostate cancer treatment capabilities through its Varian TrueBeam radiotherapy system, offering appropriately selected patients stereotactic body radiation therapy (SBRT) that can be completed in as few as five treatment sessions.
The system, available through Radiation Oncology at Mercy, is configured to deliver image-guided radiation therapy , SBRT, volumetric-modulated arc therapy, and other advanced techniques. It pairs image guidance with focused radiation delivery intended to target the prostate while limiting exposure to surrounding healthy tissue.
According to Kelly Orwat, MD, director of radiation oncology at Mercy, the system can target tumors with accuracy in increments of less than a millimeter and can deliver high-dose treatments in short treatment sessions.
“The evolution of radiation technology has given us an extraordinary ability to be precise,” says Orwat in a release. “With prostate SBRT, we’re delivering a very high dose to a very specific target, so our ability to see the treatment area, account for positioning, and carefully shape the radiation dose is extremely important.”
Orwat, who has previously worked with CyberKnife and linear-accelerator-based platforms, says TrueBeam integrates imaging, radiation delivery, and treatment planning in a single system.
“What is exciting about TrueBeam is the way it brings together highly sophisticated imaging, radiation delivery, and treatment planning in one platform,” says Orwat in a release. “For appropriately selected prostate cancer patients, that gives us a very powerful tool for delivering SBRT with a high degree of precision and efficiency.”
Addressing Motion Management Challenges
Prostate SBRT presents a technical challenge because the prostate sits close to the bladder and rectum and can shift during treatment as those organs change. TrueBeam’s onboard imaging allows the treatment team to localize the treatment site and make real-time adjustments, using three-dimensional imaging to target tumors while reducing exposure to surrounding tissue, according to a release from Mercy.
“The prostate is not a completely stationary target,” says Orwat in a release. “That is why image guidance and motion management are so important. We want to know where the prostate is when we’re treating it—not simply where it was when we planned the treatment.”
As part of the expansion, Orwat has introduced fiducial marker tracking for prostate SBRT at Mercy.
“Tiny gold markers are placed in the prostate and can be clearly seen during treatment. This helps the radiation team pinpoint the prostate’s exact location and deliver the radiation more accurately,” says Kai Dou, senior medical physicist at Mercy, in a release. “That’s especially important because standard X-ray and CT imaging don’t always provide a clear view of the prostate and the surrounding soft tissue.”
Studies of Varian’s intrafraction motion-review technology have found that it can detect prostate displacement during treatment and help assess the effect of motion on target coverage.
VMAT Delivery and Treatment Efficiency
TrueBeam delivers SBRT through volumetric-modulated arc therapy, in which the linear accelerator rotates around the patient while modulating the radiation beam, allowing radiation to be shaped around the treatment target from multiple angles.
For eligible patients, one of the most significant practical advantages of prostate SBRT is the ability to complete radiation treatment in five sessions over approximately two weeks, rather than requiring daily treatments over many weeks.
“For patients who are candidates for SBRT, five treatments can make a tremendous difference in terms of convenience,” says Orwat, in a release. “But the number of treatments is only one part of the equation. Our priority is selecting the right patients and delivering the right treatment with the precision that prostate cancer requires.”
Multidisciplinary Care Model
The expanded TrueBeam-based SBRT program is part of Mercy’s multidisciplinary prostate cancer care approach, with Radiation Oncology collaborating with Urology Specialists of Maryland at Mercy on patient evaluation and treatment planning.
“Every prostate cancer patient is different,” says Mercy urologist Damon Davis, MD, in a release. “The cancer characteristics, the patient’s overall health, anatomy, preferences, and many other factors have to be considered. We work closely with our radiation oncology colleagues so that patients can have an informed discussion about their treatment choices and what may be most appropriate for them.”
Mercy’s Radiation Oncology department is accredited through the American College of Radiology Radiation Oncology Practice Accreditation Program, which evaluates clinical personnel, equipment, treatment planning, patient records, safety policies, and quality-assurance practices.
Photo caption: TrueBeam is an advanced stereotactic radiation therapy system which delivers concentrated beams of radiation to tumors anywhere in the body.
Photo credit: Mercy Medical Center
