EXAMINING THE VALUE OF DIGITAL PET/CT - Philips
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
EXAMINING
THE VALUE OF
DIGITAL PET/CT
The Changing PET/CT Landscape
P
ositron emission tomography/ using combined scanners such as PET,
computed tomography offers a promising outlook for nuclear
(PET/CT) can be a valuable medicine. The advancements in vari-
diagnostic and prognostic ous approaches for PET are expected to
tool in the assessment of strengthen the personalized medicine
patient response to therapy and cancer industry, and continued growth is antici-
recurrence. It can ultimately even impact pated in the global market.
the choice of therapy. The significance of Efficiency and effectiveness go
this hybrid imaging modality has great hand-in-hand in clinical medicine,
Melinda Taschetta-Millane potential to flourish in future years. and digital PET addresses them both.
Editorial Director In 2017, the number of clinical PET and This supplement, written by industry
PET/CT scans performed in the U.S. was consultant Greg Freiherr, will take a
estimated at 1.9 million, a net increase close look at the significance of this
of about 13 percent over 2015, accord- hybrid imaging modality and discuss
ing to the IMV 2018 PET Imaging Market how precision can have an enormous
Summary Report. These scans were per- impact on patients. From diagnosis to
formed at about 2,400 sites using fixed or patient monitoring (see “How Digital
mobile PET, PET/CT or PET/MR scanners. PET/CT Can Improve Clinical Care”),
This device market accounted for $1.5 from the selection of therapy to its
million in 2016, and is estimated to reach assessment (see “Digital PET Balances
$2.1 million by 2023, growing at a CAGR Scan Time and Resolution”), a digital
of 5 percent during the analysis period detector built into PET/CT systems
of 2017-2023, according to Allied Market can help make positron imaging more
Research data. precise (see “What Precision Means to
Undoubtedly technological advance- PET”). And finally, Greg will discuss
ments including the time of flight (TOF) how the industry is working to push
and rise in popularity of hybrid imaging molecular imaging forward in “Digital
systems play an important role in this Technology Pushes PET In New and
market’s growth. And, hybrid imaging, Old Directions.”
Melinda Taschetta-Millane
Editorial Director
PUBLISHED BY IMAGING TECHNOLOGY NE WS, SPONSORED BY PHILIPS HE ALTHCARE
How Digital PET/CT Can Improve
Clinical Care
By Greg Freiherr
P AN IMPROVED PATIENT
ET/CT can be indispensible as a
EXPERIENCE IS THE MAJOR
diagnostic and prognostic tool;
in the assessment of patient
ADVANTAGE OF DIGITAL PET/CT
response to therapy and cancer
recurrence; even in the choice of
therapy. And the significance of this hybrid
imaging modality could grow in future years. Brian Gordon, M.D.
Digitalization is increasing the medical WellStar Kennestone Cancer Center
value of PET/CT, according to Brian Gordon, Marietta, Ga.
M.D., who interprets the majority of digital
PET/CTs performed at the WellStar Ken- cancer recurrence.
nestone Cancer Center in Marietta, Ga. Although shorter scan times have
“An improved patient experience is the boosted throughput at the cancer center
major advantage of digital PET/CT,” said Gor- and improved the patient experience, ac-
don, head of Nuclear Medicine for Quantum curacy is the top priority, Gordon said. The
Radiology, a subspecialty radiology group increased sensitivity of the digital detector
that interprets images for the sprawling improves image quality, while short scan
WellStar Health System. times make the patient more comfortable
The digital detector built into the Vereos and less prone to movement. This reduces
PET/CT from Philips Healthcare improves the likelihood of motion artifacts that can
sensitivity and, consequently, the detect- degrade images.
ability of small lesions. And it does so while The short scans do not reduce image qual- Digital PET/CT, achieved using Vereos from Philips
reducing scan time. ity, Gordon emphasized. On the contrary, Healthcare, can spot even a small lesion (arrow).
Image courtesy of Brian Gordon, M.D.
“We have seen a significant decrease in compared with analog PET/CT that operated
scan time,” he said. “About a third of the scan before Vereos, he said, “we are able to detect
time has been removed.” activity in smaller lesions.” straightforward, he said, as exemplified when
The ability to detect very small lesions is deciding whether a lesion may be resectable
PATIENT FIRST critically important when PET/CT is applied or if radiation or chemotherapy should be
The result is an enhanced patient experience, in staging or monitoring. This is where the administered first. “If you can localize exactly
according to Gordon. The Vereos replaced an digital detector excels, according to Philips’ where (the lesion) is, you can make better
analog PET/CT at the WellStar Kennestone director of Clinical Science for Nuclear Medi- decisions,” Gordon said.
Cancer Center in November 2017. Since then, cine Piotr Maniawski. The clinical prospects of PET/CT are
PET/CT scan volume has reached as high as “Digital technology allows us to improve derived from the relative certainty possible
18 patients per day. small lesion detectability,” said Maniawski, with the digital detector, Maniawski said. But
Despite the high throughput, which who has worked in nuclear medicine for more academic science advances cautiously.
ranges from this peak to about a dozen scans than three decades. Several collaborative projects between
per day, scan accuracy is excellent, he said. Philips and academic centers are underway
The WellStar Kennestone Cancer Center TRANSITION TO DIGITAL using Vereos “to deliver clinical proof not
is one of the busiest PET/CT providers in the The difference digitalization can make is ap- only for competitive differentiation (digital
state of Georgia, he said. The digital detector parent during tumor boards at the WellStar versus analog) but also to push molecular
has dropped scan times for whole body exams Kennestone Cancer Center. Vereos delivers imaging forward,” he said.
from 50 to 30 minutes and ones from the base digital PET images, which can be fused with
of the skull to mid-thigh from 30 to 20 minutes. ones from CT, Gordon said. These colorized, *Disclaimer: Results from case studies are not predic-
The vast majority of scans at the center fused images “improve the discussion be- tive of results in other case studies. Results in other
are oncologic. Many are ordered to evalu- cause the clinicians can see what I am talking case studies may vary.
ate suspicious lesions that were spotted about,” he said.
initially on CTs or MRIs, but Vereos is Clear communication is especially impor-
TO READ THE FULL ARTICLE,
also used extensively to monitor patient tant when planning patient management in
VISIT WWW.ITNONLINE.COM/DIGITALPETCT1
response to cancer therapy and to look for tough cases, when therapy choices are not
2 EXAMINING THE VALUE OF DIGITAL PET/CT
Digital PET Balances Scan Time
and Resolution
By Greg Freiherr
E
fficiency and effectiveness are spaces to minimize the movement that can
inseparable in clinical medicine. cause image artifacts.
Digital PET addresses them Although the scans may be substantially
both. The key is the detector built shorter — five or even three minutes versus
into Philips Healthcare’s digital the 15 needed with an analog detector —
Vereos PET/CT. Vereos’ PET acquisitions can still deliver high
Because photons generated during a PET diagnostic quality, he said.
exam are counted individually, digital detec- Development of the Digital Photon Count-
tors can record more such events per second ing (DPC) technology, which serves as Vereos’
than analog ones. backbone, is the latest pivotal moment in
The University of Vermont Medical Center the history of PET/CT, according to Dhruv
(UVMC) often leverages this on its Vereos Mehta, a senior product manager at Philips
to produce images with very high quality. Healthcare. The first occurred some 20 years
Alternatively, UVMC uses Vereos to shorten ago with the hybridization of PET with CT.
scan time while still producing diagnostic The second was the development of time of
quality images. flight (introduced first-to-market by Philips
Staging F18FDG PET/CT images of adenocarcinoma
“When there is a big leap in sensitivity like Healthcare), which helps localize lesions and in the RUL (right upper lobe) of the lung illustrates the
you see from analog to digital, you have to improves signal-to-noise. Fully digital PET value of Vereos. The primary lesion in the right upper
lobe appears in the upper row (PET image is left, CT
look at what you are going to do with it,” said with DPC technology is the latest advance-
image is right). A 3 mm synchronous primary or meta-
Jay Kikut, M.D., director of nuclear medicine ment affecting this hybrid, Mehta said. static lesion in the RUL is apparent in the lower row.
and PET/CT at the UVMC. “For oncology “It is really the next generation of PET/CT,” The precision afforded by Vereos’ images provided
the basis for the patient to undergo RUL lobectomy
patients, our decision is clear — we want to he said. instead of thermal ablation of the primary lesion.
use it for improved image quality.” The difference between digital and analog Image courtesy of Jay Kikut, M.D., and UVMC.
This is paramount when clinicians use PET is akin to the difference between projec-
Vereos to make diagnoses and stage cancer tion and LCD televisions. The digital architec-
patients. “Vereos provides us very accurate ture of LCD TVs, he said, delivers a sharper
staging of our patients,” he said. “To have the image, higher efficiency and more dynamic under five minutes, however, “is a substantial
best outcome, you have to match the treat- range. Digital PET does much the same in improvement.”
ments to the stage.” Exactly staging patients molecular imaging. This linkage between im- Very relevant when making purchasing
leads to a more individualized choice of age quality and dynamic range is important, decisions, he said, is the increased precision
therapy. Mehta said, when trying to go beyond the that digital PET offers and the hedge that
Oncological applications account for current FDG-based oncology applications Vereos provides against obsolescence. At
about 80 percent of PET scans done at into emerging applications in neurology and present, PET is one of the few commercial
UVMC. (The remaining 20 percent of PET/CTs cardiology and emerging tracers. modalities with high-end systems that are
examine the heart or brain.) “With a shorter acquisition, the patient still analog, he said. That, however, could
When set to deliver maximum spatial is less likely to move,” he said. “The clinical change.
resolution, the increased sensitivity achieved benefit is that you have a better study with “We envision a time in the future when all
through digital PET is used to detect very less motion. As a result, you can visualize PET/CT is digital,” Mehta said.
small lesions. Alternatively, some patients at lesions better.”
UVMC are best served by scans that mini- Mehta cautions that many factors beyond
mize time spent inside the PET/CT bore. Such the scanner may affect throughput at a facil-
TO READ THE FULL ARTICLE,
shorter exams might be chosen for children ity. Chief among them are ones related to
VISIT WWW.ITNONLINE.COM/DIGITALPETCT2
or patients who are uncomfortable in tight patient management. Cutting scan time to
EXAMINING THE VALUE OF DIGITAL PET/CT 3
What Precision Means To PET
P
By Greg Freiherr recision can have an enormous scanner is why speed was a big factor in the
impact on patients. choice of Vereos, said Brennan: “Because we
From diagnosis to patient share the system with CT, we have a lot of
monitoring, from the selection patients who want to get in, so we have to
of therapy to its assessment, the use (Vereos) efficiently.”
digital detector built into Philips Vereos PET/ Because Vereos includes a 64-slice Ingenu-
CT makes positron imaging precise. ity CT from Philips, “anything you can do with
The digital detector, and the Vereos digital an Ingenuity CT you can do with the Vereos
architecture, are a big part of the scanner’s CT,” said Karim Boussebaa, Philips’ business
efficiency, said Tom Brennan, service leader leader for CT/Advanced Molecular Imaging.
of imaging for Nebraska Methodist Health
Systems in Omaha. Staff at its Methodist Hos- EFFICIENCY
pital in midtown Omaha use Vereos PET/CT Vereos was chosen by Methodist Hospital
to do seven PET scans a day — and about 20 to replace an aging analog system, one that
CTs. Slots for PET patients are scheduled in also handled overflow CT scans “but didn’t
pairs. In between, Vereos’ 64-slice CT handles do nearly as well,” Brennan said. The analog
patients who can’t be seen on the three CT system “was much slower and less reliable.”
scanners on the main campus or a fourth at a Brennan credits the digital architecture of
neighboring hospital in the network. Vereos for making “it a more reliable system.”
The need to do double duty on the hybrid The vast majority of PET scans are oncologic,
PET images taken on Philips’ Vereos PET/CT at
Methodist Hospital in Omaha, Neb., show a lung
lesion. Caveat: Because results may vary, “results
from case studies are not predictive of results in other
cases,” Philips cautioned. Image courtesy of Omaha’s
Methodist Hospital, Nebraska.
4 EXAMINING THE VALUE OF DIGITAL PET/CT
THE SPEED OF
patients are return patients. Vereos is the
preferred tool to measure how treatments
VEREOS HAS HELPED
are going,” Brennan said.
Staying on schedule is very important for
these patients, he said, because they typi-
US BECOME BETTER AT
cally depend on having results from multiple
tests available at the same time. “Access
GETTING PATIENTS IN
is important. The speed of Vereos has helped
us become better at getting patients in
on time,” he said.
ON TIME EXTENDING PATIENT COMFORT
Patient comfort depends on feeling good.
And Philips’ Ambient Experience directly
Tom Brennan, addresses this in several modalities including
CT and PET. “Ambient has shown some good
Nebraska Methodist results for reducing the level of stress,” said
Philips executive Boussebaa. “It can really
Health Systems, Omaha make a difference with kids.”
A mix of lighting and sound — movies
projected on walls, for example — might
according to Brennan, who explains that the 12 mCi,” Brennan said. “What that did for us combine to reduce stress, he said. These
main campus hosts a major cancer center. is drop all of our doses into that lower price combinations can increase patient satisfac-
Fluorine-18 deoxyglucose (FDG) is the radio- tier, which saves us about $25,000 per year.” tion, which has become a major survey item
tracer of choice, although gallium 68 is occa- High efficiency is possible with no com- for hospitals.
sionally applied to visualize neuroendocrine promise in image quality because of the Greater patient comfort can make patients
tumors and yttrium-90 is used to treat and one-to-one coupling between sensor and easier to manage, which can make technolo-
visualize liver metastases. The staff some- scintillation event. “Each of the 23,000 detec- gists’ jobs easier. In this way, Philips’ Ambient
times — but rarely — performs a myocardial tors has its own little counting chip, which I Experience improves working conditions for
viability study, Brennan noted. think leads to the amazing spatial resolution,” hospital staff.
Vereos’ digital technology can be lever- Brennan said. “That goes back to the heart “The question is how to make people
aged to reduce radiopharmaceutical dosing. of why it is fast and why the image quality is happy,” he said. “If you do that, patients will
At Methodist Hospital in Omaha, staff inject so good.” come back and staff will stay.”
lower doses of PET radiopharmaceuticals At Omaha’s Methodist Hospital, PET scan According to Boussebaa, health care
than when they used Vereos’ analog prede- times have dropped from 24 to 12 minutes administrators are coming to realize that
cessor. Doses of FDG now are typically 30 on the Vereos compared to the preceding patient comfort has a role in being efficient
percent lower than ones administered to analog system, according to Brennan. Patient and effective.
patients before the hospital switched from slots have been reduced from 45 to 30 min- With its emphasis on precision, Vereos ad-
an analog PET/CT to Vereos in early summer, utes. This has resulted in greater availability dresses patient comfort, the components of
according to Brennan. This has allowed the of PET and CT exams. value-based medicine — and the future.
hospital to take advantage of the lower The increased efficiency achieved with
pricing tier of FDG that is available to Vereos means Methodist Hospital patients
Methodist Hospital. not only spend less time being scanned but
TO READ THE FULL ARTICLE,
“We went from a weight-based dosing less time waiting for appointments. This is
VISIT WWW.ITNONLINE.COM/DIGITALPETCT3
system to one of standardized doses of just important because “three out of our four
EXAMINING THE VALUE OF DIGITAL PET/CT 5
Digital Technology Pushes PET In New and
Old Directions
D
By Greg Freiherr igital technology is opening “Seeing if the texture is changing helps
remarkable opportunities characterize the lesion,” said Maniawski. The
for clinical positron emission metabolism inside the lesion, he said, may be
tomography (PET) about much different, depending on the location.
which research is only In a paper published May 2017 in the
beginning to hint. journal Contrast Media and Molecular Imag-
“Twenty years ago we were excited that ing, Knopp, who is the Novartis chair of
we could see a lesion. Now we want to Imaging Research at Ohio State University,
understand its underlying biologic heteroge- and colleagues at Ohio State summarized
neity,” said Michael Knopp, M.D., a radiology how digital PET enables advanced functional
professor at Ohio State University whose tumor imaging.
research with Philips’ digital PET/CT, called
Vereos, is exploring applications within and A DIGITAL TWIST
beyond traditional clinical areas. Much like how radiography began, PET
The digital technology underlying Vereos started as an analog modality. Instead of film,
can provide the details that may escape PET relied on photomultiplier tubes (PMTs).
analog systems, said Piotr Maniawski, In analog systems, light generated by a
director of clinical science for nuclear single scintillating crystal is channeled to
medicine at Philips Healthcare. Visualization multiple PMTs. In Vereos, light generated by
using 4 mm cubes, which are typically a single scintillating crystal is channeled to
delivered by analog systems, makes small its own detector.
lesions look spherical, he said. The very small Vereos’ digital detection is built on digital
voxels in digital images better visualize photon counting (DPC) technology, whereby
shapes and texture. crystals and sensors are coupled “one-to-
A 90-second brain acquisition with FDG radiotracer
— comparison of digital (Vereos, left, 1 mm) and
conventional (Gemini TF, 4 mm) images.
6 EXAMINING THE VALUE OF DIGITAL PET/CT
Why—And How—Digital PET Is
one,” said Maniawski, who has worked with Knopp and others
Better Than Analog
to assess the clinical capabilities conferred by Vereos’ digital
technology. Light flashes produced by specific crystals are Fully
channeled directly to individual digital sensors. In stark con- digital
trast to analog technology, which accumulates signals from interface
light flashes in analog detectors until reaching trigger points,
“there is no light sharing,” Maniawski said. “The moment the
detector registers this light, we know precisely which crystal Each digital photon counter in the Vereos
produced it.” PET/CT detector contains thousands of
solid-state sensors that digitally count
Reconstruction algorithms onboard Vereos mathematically individual photons.
reconstruct digital PET into detailed images. These appear
“more rich and precise” than those made using analog-based
PET systems, Knopp said, due to the increased density of the Analog is approximate. Digital is injected into a patient create high-
data. The OSU researcher likened the benefit of data density specific. Therein lies the fundamental energy photons. When these photons
to the improvement of smartphone images as those pictures difference between digital PET and its crash into scintillation crystals in
gain more data density. analog cousin. the detector, they are converted into
We see this difference every day in optical ones. This is where the type of
“When you pull up Google maps, the picture might look
clocks, one displaying numbers, the detector matters.
fuzzy at first and then as the data come in, it will look sharp other telling time with big and little The digital detector in Vereos
and brilliant,” Knopp said. “This happens because the data hands. Digital and analog versions counts optical photons individually.
density changes.” of PET are like that, but much more “With one-to-one coupling between
Maniawski explained that voxels in Vereos images are sophisticated, according to Michael the scintillation crystals and the digital
A. Miller, Ph.D., a physicist at Philips sensors, there are many channels,
densified with data collected by the 23,000 solid-state sensors
Healthcare. each with a relatively low count rate.
from individual scintillation events. This added data density The digital photon counting detec- So we end up with good count rate
allows Vereos to package data into voxel volumes of 2 mm tor, which is the backbone of Philips’ performance,” Miller explained.
— or even 1 mm — cubes. This data density gives shape and Vereos PET/CT, uses solid-state The resulting accuracy supports
texture to structures in the images. sensors to count the individual scintil- enhanced performance in time of
lation photons created during a PET flight (TOF) calculations, Miller said.
scan. Analog PET detectors cannot These, as the name implies, reflect the
BRINGING TOGETHER OLD AND NEW count individual photons. Instead millionths of a second in which the
The game-changing appearance of Vereos’ images can be these detectors, which are built into high-energy photons are in flight and
challenging, Knopp noted. the vast majority of installed PET/CTs, provide the basis for determining the
Because digital images show more detail, they may show record flashes of light. locations of the radiopharmaceutical
If lettuce farmers used similar tech- in the patient’s body. Consequently,
lesions and features that might not be seen with analog
nologies, their digital detectors would Vereos excels at helping physicians
technology. When comparing current digital images to past count the leaves of lettuce. Analog de- detect cancer, which typically involves
analog ones, the question arises: Were lesions now visible not tectors would count the heads. When the radiotracer, fluorodeoxyglucose
seen previously because the technology could not see them? applied to clinical medicine, exactness (F-18 FDG).
Or have they just recently occurred? translates into options, said Miller,
The answers to these questions can directly impact the who specializes in CT and advanced PET/CT HISTORY
molecular imaging. PET itself goes back to the early 1970s,
management of patients being monitored for disease recur- Vereos can be used to increase the when photomultiplier tubes were used
rence. quality of patient images compared to record scintillation flashes. Today
To deal with this incompatibility, Philips offers a feature in to those obtained with analog PET/ many installed PET/CTs rely on this
Vereos that reconstructs digital data as if they were acquired CT, making lesions easier to detect. inherently analog technology.
Alternatively, the digital PET/CT might By contrast, Vereos uses digital
on an analog system. This is done with reconstruction
maintain image quality achieved over technology. Data for its PET im-
algorithms, Maniawski said. These algorithms harmonize the a substantially reduced scan time, as ages are obtained from solid-state
digital data. low as one-third or less of the typical silicon tiles, which are arranged in a
Vereos users who choose this option “end up with two im- 10 to 15 minutes. Or, physicians might many-sided polygon that encircles
ages from the same data — a conventional looking image and choose a third option: to maintain im- the patient. Light sensors and data
age quality and scan time but reduce processing arrays are hardwired into
a digital one,” Maniawski said.
the dose of radiopharmaceutical these tiles. Putting them together
Vereos can create a still picture and visualize changes over injected into the patient. makes photon counting fast, accurate
time. In the mid- to late-1980s, early developers of PET often “The detector allows us to get and free from the electronic noise
acquired data dynamically. Serial acquisitions came into better data and do better corrections,” produced in analog systems.
vogue when PET/CT imaging entered the mainstream. But Miller said. This, in turn, creates higher “Vereos achieves high imaging
quality images. performance, which supports clinical
dynamic imaging, similar to short video clips, can provide
needs and is facilitated by (digital)
clinical information not found in static images.
HOW PET WORKS technologies,” said Miller, who puts
Regardless of whether the detector is Vereos at the apex of the PET/CT
TO READ THE FULL ARTICLE, VISIT digital or analog, PET imaging oper- hierarchy. “It really gives people what
ates on the same principles. Positrons they’re looking for when they want it
WWW.ITNONLINE.COM/DIGITALPETCT4
released by a radiopharmaceutical — without any questions.”
EXAMINING THE VALUE OF DIGITAL PET/CT 7
Vereos Digital PET/CT Proven accuracy inspires confidence In the transition from volume- to value-based care, accurate treatment pathways are essential. Philips Vereos Digital PET/CT is the world’s first and only fully digital PET/CT solution—and its accuracy is supported by rigorous clinical evidence measured in years, not months. There is always a way to make life better. Visit philips.com/vereos to learn more.
You can also read
