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Centers Around the World
“On Board” with
The needs of every radiation oncology practice are
as diverse as the patients they serve. No two cancer
cases are alike, and the days of the “one-size-fits-all”
treatments are rapidly coming to an end.4
Supplement sponsored by an educational grant from
Varian Medical Systems
Centers Around the World “On Board” with Varian IGRT
Speed, precision and versatility are at the perfectly reasonable dose distribution, while
lesions require non-co-planar beams in
heart of Varian’s technology for image- other
order to adequately protect sensitive tissues and
guided radiotherapy (IGRT). This article organs nearby. Varian technology is designed to
highlights some select case examples enable the best possible treatment for any set of
clinical circumstances.
that show how clinicians are taking full
advantage to provide their patients with LUNG CANCER
Adapting the Treatment as the
optimal treatments.
Tumor Responds
Varian’s approach to image-guided radiotherapy utilizes a spectrum of imaging and motion
management technologies to pinpoint and target
tumors with tremendous speed and accuracy,
rapidly changing the outlook for cancer treatment around the world. These include Varian’s
On-Board Imager® (OBI) device for generating
high-resolution radiographic, fluoroscopic and
cone-beam CT kV images right at the treatment machine, as well as the Real-Time Position Management (RPM) system for respiratory gating and motion management during
treatment. Outfitted with these image-guidance
tools, a Varian Trilogy® or Clinac® iX accelerator offers doctors many choices for treating different disease types.
This versatility turns out to be clinically important, enabling doctors to choose between
different treatment approaches according to the
dictates of a particular situation. For example:
The optimal approach for treating one patient
with a small lung tumor might be to use a gated
10-field stereotactic body radiotherapy (SBRT)
treatment delivered over three fractions of 20
Gy each, based on radiographic images of an
implanted fiducial marker. For another patient
with a larger lung lesion, it might make more
sense to use a conventional six-week schedule
to deliver 1.8 Gy per fraction, to allow more recovery time for the limited normal lung volume
that remains. In the latter case, implanted markers might be contraindicated, and cone-beam
CT imaging could be used to localize the target
and to track tumor response over time. Similarly, for some lesions, a simple IMRT treatment
delivered with co-planar beams might yield a
TM
2 Varian Medical Systems | October 2007
Vasudha Lingareddy, MD, medical director of
radiation oncology at the Edward Cancer Center
in Naperville, Ill. uses Varian’s Trilogy accelerator for adaptive stereotactic body radiotherapy
(SBRT) in exceptionally difficult lung cancers.
Treatment plans are adapted as the patient’s tumor responds to treatment and changes in volume. Cone-beam CT imaging makes this possible.
A recent case involved a 69-year-old female
patient with a sizeable small-cell lung cancer tumor that was growing quickly. “Her respiration
was becoming seriously compromised, so we
started radiotherapy immediately to reduce the
tumor volume,” explains Lingareddy.
Lingareddy’s clinical team used the kV-MV
image matching feature of the On-Board Imager
each day to position the patient for treatment. No
fiducial markers were placed into the target area,
so the matching was accomplished based on
clearly visible soft tissue and bony structures.
The PortalVision™ MV imager was used in
cine mode on the first two days of treatment to
analyze the respiratory motion and make sure
that treatment margins were adequate. Since
then, Lingareddy says, Edward Hospital has
added 4D-CT imaging as well as RPM™ respiratory gating, so she can incorporate tumor motion
into her treatment plans and gate the beam during
these types of treatment. Lingareddy prescribed
delivery of 1.8 Gy per fraction, keeping the dose
low to protect surrounding lung tissue because
of the volume of the tumor and also because the
patient was receiving a concurrent course of chemotherapy.
After a couple of weeks, when the patient’s
lungs were reaching 16 Gy, cone-beam CT images revealed that the tumor had shrunk sufficiently
for Lingareddy to significantly reduce the area
being treated. “We checked at that point because,
beyond 20 Gy, normal healthy lung tissue can be
compromised,” Lingareddy says. “We were able
to shrink the field size from 13.2 by 14.6 centimeters down to 11 by 9 centimeters. That’s a
reduction in volume of over 75 percent, from 450
cubic centimeters to 104.6 cubic centimeters.”
Two weeks later, the clinical team created
yet another treatment plan to better protect the
patient’s spinal cord, which was approaching its
maximum dose tolerance. When all three of the
plans were summed, only 21 percent of the pa-
LEFT | Image taken at the start of treatment shows complete occlusion of the right lung. Note the impossibility
of distinguishing between the tumor and other lung tissues.
RIGHT | Image taken approximately two weeks into treatment shows considerable tumor regression. A new
plan could be adopted to protect more healthy lung tissue.
Centers Around the World “On Board” with Varian IGRT
tient’s normal lung tissues had received 20 Gy or
more. Had Lingareddy stayed with her first plan,
nearly 40 percent of the lung tissue would have
reached that dose, and that would have been too
much. “Making those adaptations enabled us to
save more of her normal lung tissues,” Lingareddy says. “It meant the difference between being
oxygen-dependent or not.”
Gating the Beam to Manage
Motion
Doctors at the University of Pittsburgh Medical
Center (UPMC) are using Trilogy with the RPM™
system to adapt to intrafraction tumor motion during treatment.
Dwight Heron, MD, associate professor and
vice chair of clinical affairs in UPMC’s department
of radiation oncology, describes the case of a lung
cancer patient in her mid-50s, for whom the RPM
system was used to synchronize beam delivery with
her natural breathing cycle. The On-Board Imager
in fluoroscopic mode made it possible to check the
gating strategy to make sure tumor motion stayed
consistent day to day.
“We set our RPM system to deliver the treatment beam only when her tumor moved the least
during her respiratory cycle,” Heron says. “When
she was about halfway through her exhalation, the
tumor was virtually motionless so we could target it very accurately and decrease the treatment
margin to half a centimeter. We were also able to
couple her gated treatments with an IMRT plan
that further decreased the radiation dose to nearby
ABOVE | Dr. Heron and Gregory Ross, MBA, the departmental administrator at the University of Pittsburgh Medical Center, review anatomical images.
critical structures. This resulted in minimal treat- of verification and the next three just before each
ment-related toxicities.”
treatment.
“The cone-beam CT images give me a lot
Hypofractionated Treatments
of confidence when I’m getting ready to deliver
At other centers, use of Varian’s Trilogy accel- 20 Gy to a patient in one session,” he says. “You
erator is enabling a hypofractionated approach, are always going to have some set-up variation no
delivering stereotactic body radiotherapy (SBRT) matter what you do to position and immobilize
in the treatment of certain early-stage lung tu- the patient. With cone-beam CT, we can adjust for
mors, following an RTOG protocol to determine that by placing the isocenter directly in the middle
patients’ eligibility for this treatment. Bo Lu, MD, of the tumor. I know what I am doing, with the
PhD, radiation oncologist with the Vanderbilt- cone-beam CT images right in front of me.”
Ingram Cancer Center at Vanderbilt University
Jeffrey Bradley, MD, associate professor of radiin Nashville Tenn., is delivering a total of 60 Gy ation oncology at Washington University School of
in three fractions at 20 Gy each. Each patient re- Medicine in St. Louis, uses a similar SBRT protoceives four cone-beam CT scans, one at the time col. One of his patients, a 68-year-old former smoker, already had emphysema and had been hospitalized with congestive heart failure when clinicians
discovered a tumor growing in her right lung. “A
patient with respiratory disease does not have much
healthy lung to spare,” explains Bradley. “This kind
of situation tends to make a patient ineligible for invasive surgery to remove the tumor.”
Bradley successfully delivered treatment in
three fractions over the course of a week. “With
our machine I can set the patient up for treatment,
LEFT | A highly conformal treatment plan for treating lung cancer with respiratory gating.
generate CT images to verify the location of the
tumor, and make any needed positioning adjustRIGHT | Cone-beam CT images of the lung are compared with CT images from the treatment plan in order
to position the patient accurately for treatment.
ments prior to treatment, all right there in one
October 2007 | Varian Medical Systems 3
Centers Around the World “On Board” with Varian IGRT
place,” he says. “The patient is on the table for less
than half the time we would have needed with our
earlier protocols.”
At Florida’s Melbourne Internal Medical Associates (MIMA) Cancer Center, clinicians have
been using Varian IGRT to treat stage III lung lesions. “You cannot name a cancer that I do not
treat with Trilogy, whereas I can name some
cancers, such as stage III lung, for which certain
other radiosurgery treatment devices cannot be
used,” says Todd Scarbrough, MD, radiation oncologist and director of the MIMA Cancer Center. “With Trilogy, if you can see the tumor you
can treat it, whether it is the size of a pencil point
or a football.”
“You cannot name a
cancer that I do not
treat with Trilogy...
- Todd Scarbrough, MD
“
Radiosurgery tools that shape the treatment
beam only with conical collimators cannot be
used to treat large tumors or lesions. A Trilogy
machine shapes the beam with either a cone or
with Varian’s high-resolution Millennium™ multileaf collimator, which can create apertures of
nearly any shape or size. “Most radiosurgery
systems can paint pretty radiation doses inside a
patient’s body,” says Scarbrough, “but the conebased approach is like airbrushing one pixel at a
time. With Trilogy, we can saturate larger areas
much more quickly and still get precise conformality. It is the difference between slow airbrushing and fast laser printing.”
external beam prostate cancer patients
using cone-beam CT imaging. “We
place three fiducial markers in the prostate prior to the treatment planning CT
simulation,” he explains. “Knowing
their relationship to the prostate enables
us to adjust the target center for daily
variations in the prostate position. We
truly appreciate the exactness and ease
of matching prostate fiducial markers
using the 2D-2D marker match feature
of the On-Board Imager. We now have
ABOVE | Dr. James McGee is pictured with W. Gregg Devanna,
the confidence needed to tighten the
cheif medical physicist at OSF Saint Francis Medical Center.
IMRT margins and escalate the doses to
the prostate,” he says.
“We also recognize the importance of the selec- because all 240 patients were treated to a very high
tive use of the cone-beam CT (CBCT) images in dose of 81 Gy. If these outcomes hold over time,
checking for rectal movement into the portal in pa- Scarbrough said, then seed marker–based IGRT
tients whose seminal vesicles are also being treat- will have yielded “some of the lowest toxicity rates
ed,” McGee adds. “Further, the CBCT can be used of any of the definitive local treatments for prostate
daily if a patient declines marker placement.”
cancer.”
Over at MIMA, Scarbrough and his colleagues
recently completed a study of the toxicity outcomes HEAD AND NECK CANCER
of 240 patients who were treated for prostate cancer
using IGRT. Implanted seed markers were used on
At Stanford University in Palo Alto, Calif.,
a daily basis during treatment to correct for the set- radiation oncologist Billy W. Loo Jr., MD, PhD,
up and targeting errors inherent in external beam has been using Varian IGRT to treat cancers of the
radiotherapy of the prostate.
head and neck, where the major challenge is the
“At a median follow-up of 1.4 years, 98 percent very close proximity to critical and highly radiaof our patients showed grade 0 rectal toxicity, and tion-sensitive tissue. “To treat head and neck cannone showed grade 3 or greater toxicities of any cers, we need an especially high degree of precisort,” says Scarbrough. This is particularly notable sion in our treatment,” says Loo. “The On-Board
PROSTATE CANCER
A number of treatment centers use Varian
IGRT as the treatment of choice for their prostate
cancer patients.
At OSF Saint Francis Medical Center in Peoria,
Ill., James McGee, MD, medical director of radiation oncology, preferentially treats all curative
4 Varian Medical Systems | October 2007
LEFT | A color-wash representation of an IMRT plan for treating prostate cancer, shows how the
radiation dose will be distributed in and around the prostate.
RIGHT | Cone-beam CT images of the prostate (right column) are compared with CT-images from the
treatment plan (left column) in order to position the patient accurately for treatment.
Centers Around the World “On Board” with Varian IGRT
Imager enables us to perform daily patient position verification and correct for any mismatches
between the planned and the actual treatment position before every treatment. This gives us a sufficiently high degree of confidence to take on the
most challenging cases.”
Among such cases are situations in which
a tumor has invaded the skull base and is encroaching on the brain or the visual pathway.
“Daily imaging provides the quality assurance
we need to deliver complex IMRT plans with
the sharp dose gradients required for these extreme cases,” says Loo.
Nancy Ellerbroek, MD, medical director for radiation oncology at Providence Holy Cross Cancer Center in Mission Hills, Calif., agrees. She
treated a 17-year-old girl for a tumor of the nasopharynx. “Her tumor was close to her spinal cord
and had invaded the base of her skull and some
lymph nodes,” Ellerbroek says. “Prior forms of radiation therapy would have destroyed her salivary
function. We also had to be concerned about neurological structures such as the brain stem and the
optic nerve. We needed to be extremely accurate
with our targeting.”
Ellerbroek’s team treated the girl over a sevenweek period. Prior to every treatment, they used the
On-Board Imager to make very fine adjustments to
the patient’s position and line up the tumor so it
fell squarely into the center of the treatment beam.
The patient finished her treatment in October.
“By the end of the treatment, her breathing
problems had resolved, her headaches were gone,
and no more signs of cancer were detected,” Ellerbroek says. “Her loss of salivary function was only
slight - not the profound loss of function that we
would have expected.”
the end of
“theBytreatment...
no
more signs of cancer
were detected.
- Nancy Ellerbroek, MD
“
BREAST CANCER
Conventional Fractionation
In the United Kingdom, clinicians at Ipswich Hospital NHS Trust are studying the use
of IGRT to improve the quality of conventionally fractionated breast cancer treatments. They
use Varian’s On-Board Imager to generate daily
radiographic kV X-ray images to visualize implanted gold marker seeds in the breast cavity
following surgical excision of the tumor. The
goal is to deliver radiation dose to the area at
highest risk of recurrence.
“It is tailored radiotherapy which some people have dubbed ‘risk adaptive radiotherapy,”
says Andrew Poynter, cancer research lead at
Ipswich Hospital. “Our initial experiences have
been very encouraging.”
LEFT | A color-wash representation of an IMRT plan for treating head and neck cancer shows how the
radiation dose will be distributed in and around the tumor, with sparing of the spinal cord.
RIGHT | On-Board Imager software performs a 3D-3D match comparing a cone-beam CT image with
reference images from the treatment plan. It then calculates how to shift the patient in three dimensions
to bring the tumor squarely into the isocenter.
This work at Ipswich forms part of a pilot
study led by Addenbrookes Hospital in Cambridge, which is examining the feasibility of
using IGRT for post-lumpectomy breast cancer
patients. The study will provide vital data for
a national, multi-center trial to test riskadapted and partial breast radiotherapy
treatment in patients at a high risk of local
tumor recurrence.
Accelerated Treatment of the
Partial Breast
At the Siteman Cancer Center at BarnesJewish Hospital in St. Louis, Simon Powell, MD, chairman of the department of radiation oncology at Washington University School
of Medicine, offers select patients an accelerated five-day image-guided treatment option
for breast cancer. Eligible patients include
those with early-stage breast cancer that has not
spread to the lymph nodes. “Patients love it because if they are eligible and they can have their
treatment completed in a week, then they find it
a lot more attractive than having six weeks of
daily treatments,” he says.
Powell and his clinical team use the OnBoard Imager in radiographic mode for daily
target localization. For his accelerated partial
breast treatments, Powell delivers 4 Gy over
nine fractions, for a total dose of 36 Gy. He will
compare the results with other dosing strategies,
as part of a dose finding study. “We are currently completing an analysis of patients we treated
at 36 Gy,” he says. “We are seeking what dose
is biologically equivalent to the dose we are familiar with when we deliver 2 Gy each day over
six weeks. It is still an open question.”
According to Powell, the patients who receive
the image-guided accelerated partial breast
treatments do very well, in terms of adverse effects, compared with women who are treated
according to more conventional fractionation
schedules. “At worst, they might have a little bit
of very transient skin rash. By the time you see
them six weeks later, this has usually cleared up
completely.”
October 2007 | Varian Medical Systems 5
Centers Around the World “On Board” with Varian IGRT
SPINAL LESIONS
Prior to the advent of Varian’s IGRT solution,
spinal metastases were generally treated with chemotherapy or long courses of fractionated radiotherapy. According to Patrick W. Elwood, MD, director
of the Illinois Neurological Institute and professor
of neurosurgery at the University of Illinois College
of Medicine in Peoria, Varian’s Trilogy technology
enables him to use either single or hypofractionated radiosurgery to shorten the treatment time and
accelerate pain control while protecting the spinal
cord from radiation effects. “The use of kV and
cone-beam CT imaging has eliminated the need
for fiducial marker placement, allowing this modality to be used more readily, thereby reducing
the number of patients requiring extensive spinal
reconstructive surgery or being left with unrelieved
pain,” he says.
Clinicians at Providence Hospital in Mobile,
Ala., use Trilogy to deliver spinal treatments following a protocol that was pioneered by clinicians at Memorial-Sloan Kettering Cancer Center
(MSKCC) in New York. The sensitivity of the
spinal cord to radiation damage makes this an especially difficult area to treat, but IGRT smoothes
the way and offers patients with spinal lesions a
viable alternative to surgery.
Robert Gilbert, MD, radiation oncologist, treated
a 48-year-old man with lung cancer that had metastasized to the spine and brain. His brain lesion and
one of two in the spine were successfully treated
at M. D. Anderson Cancer Center in Houston, but
subsequent PET and MR scans showed an active
lesion in the spinal area. It was causing him a considerable amount of pain.
In this case, Gilbert had to be especially precise
because the spinal cord near the lesion had already
received two-thirds of the tolerance dose. “We were
able to use image-guided IMRT to keep the dose
away from the spinal cord,” he says. “The Trilogy
technology is perfect for just this kind of situation.”
The On-Board Imager was used to detect a fiducial marker that had been placed into the targeted
area under the periosteum. According to Gilbert,
kV X-ray imaging is ideal for showing titanium or
gold markers. “They show up beautifully,” he says.
“The titanium markers are easier for the neurosurgeons to place. We would not be able to see them
with megavoltage imagers.”
Gilbert delivers these treatments in daily sessions
over a five-day period. “At MSKCC, they are up to
delivering 600 cGy per fraction, but they started out
at a lower dose, and we are doing that as well,” he
says. Gilbert is delivering 500 cGy per fraction and
plans to escalate up to 550 if he sees good tolerance
over a reasonable number of cases.
“Today, if the original tumor is well-controlled
using radiotherapy, chemotherapy, surgery or
some combination of these, in many cases we
can use radiosurgery or stereotactic radiotherapy
to target the metastases and significantly prolong
life,” Gilbert says. “We are seeing lung and brain
cancer patients with metastatic disease living three
LEFT | An image-guided radiosurgery treatment plan for a lumbar spinal metastasis.
RIGHT | The nine-beam plan enables a high level of dose conformity with sharp dose fall off in the
direction of the spinal cord.
6 Varian Medical Systems | October 2007
or four years and longer. That is because stereotactic approaches for delivering IMRT enable us
to treat these lesions much more aggressively than
we could have before.”
MULTIPLE BRAIN LESIONS AND
METASTATIC SPREAD
Clinicians at the Virginia Commonwealth
University Massey Cancer Center in Richmond,
Va., were among the first in the world to control
the spread of metastatic cancer using a Trilogy
machine to deliver image-guided radiosurgery
(IGRS). Theodore Chung, MD, PhD, radiation
oncologist and associate professor at the VCU
School of Medicine, used the technique to help a
47-year-old mother of four whose breast cancer
had spread to her brain and liver.
Chung and his team use the On-Board Imager
along with Varian’s FramelessArray™ optical imaging system to pinpoint tumors and to continuously monitor and ensure that the patient remains
properly positioned during treatment. The team
also uses Varian’s RPM respiratory gating system to synchronize beam delivery with patients’
breathing patterns.
For the patient with metastasized breast cancer, Chung and his team were able to treat all
three brain lesions in a single course of treatment.
The optical positioning system made it possible
to avoid using a conventional head frame.
“One lesion was close to the motor strip,”
Chung says. “Too much dose to this area might
have damaged her ability to move. The second
lesion was close to the brain stem. By using the
On-Board Imager to take radiographic X-rays,
we were able to quickly line up bony anatomical landmarks each day and position the patient
properly for her treatments.”
To deal with the metastatic tumor in the patient’s liver, Chung and his team compensated
for respiratory motion with a gated radiosurgery
treatment. The Massey Cancer Center was one of
the earliest adopters of Varian’s RPM system for
targeting tumors that move during treatment due
to the patient’s breathing.
Centers Around the World “On Board” with Varian IGRT
RECURRENCES
Metastatic lesions, or cancer that has spread
beyond the original tumor site to other organs,
have been notoriously hard to treat, but Varian
IGRT is making it possible to treat many forms
of metastatic and recurrent disease, according to
Michael Greenberg, MD, radiation oncologist
at the Dales and Frances Hughes Cancer Center in East Stroudsberg, Pa. “As we get better
and better at treating cancer, we are going to see
more and more of these second malignancies.
It is becoming a significant component of our
practice,” he says.
“In many cases, people receiving treatment at
centers that do not have the latest IGRT technology are told they can’t receive any more
radiation. IGRT makes it possible for us to
treat patients successfully a second and even
a third time with radiation,” Greenberg points
out—sometimes even when the recurrence is at
or near the site of the original tumor.
For example, one of Greenberg’s patients, a
man in his mid-60s who had been treated several years ago for esophageal cancer, developed
bilateral pulmonary nodules with spread into
the lymph nodes. This patient had a long cardiac
history that precluded surgical intervention, and
he was also not a candidate for chemotherapy.
Greenberg was able to treat him with gated
IGRT delivered over 30 fractions, however.
“We did not hypofractionate in this case be-
ABOVE | A treatment plan for simultaneously
treating multiple brain metastases with a single
isocenter. This type of treatment can be delivered
in only 30 minutes using Varian’s Trilogy machine for image-guided radiosurgery.
ABOVE | Michael Greenberg, MD, talks with a patient about image-guided radiotherapy for a metastatic
lesion that appeared on her adrenal gland
cause we thought normal tissue repair would be
better with normal fractionation,” he says. “We
were, of course, worried about overlapping the
treatment fields with areas that had been previously irradiated. We used PET/CT to help us really localize the cancer, and fused those images
with the treatment planning CT scan to make
sure we were very tight on the targets.”
Greenberg chose a sophisticated strategy for
managing tumor motion in this case, because of
the need to spare as much healthy lung tissue as
possible. He used retrospective 4D CT scanning
to generate the images for treatment planning,
and created his plan using only images that corresponded to the relevant respiratory cycle phase.
In the treatment room, the On-Board Imager was
used to generate radiographic kV images to position the patient for treatment, as well as fluoroscopic images to check on the respiratory gating
thresholds.
“The goal was to prevent pneumonitis and
pericarditis,” Greenberg says. “The ability to
treat recurrances in the head, neck and prostate,
along with metastatic lesions in the brain, liver,
lungs and spine, is a major advantage for cancer centers that can offer patients the precision
of Varian IGRT.
PERSONALIZED CANCER CARE
In highlighting the advantages of IGRT,
Ellebroek points out that having the ability to
generate images on a daily basis is immensely reassuring when she is delivering high
doses of radiation to tumors close to critical
structures in the body. “It allows me to deliver the powerful doses we know are better
at eradicating tumors without cutting corners
because we are afraid of getting too close to
something crucial,” she says. “That means we
can target tumors we would have considered
untreatable just a year ago. I expect our tumor
control rates will improve and our complication rates will be lower, when we have had a
chance to study IGRT outcomes over a longer
period of time. So far, our experience bears
this out.”
UPMC’s Dwight Heron agrees. “Technologies like these make it possible for us to adopt a
truly personalized approach to cancer care,” he
says. “Having a full integration of technological
solutions that enable state-of-the-art, innovative
treatment paradigms for a variety of cancers
gives us the power to truly tailor cancer treatment for each and every patient.”
October 2007 | Varian Medical Systems 7
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