PET & SPECT
Auto-injection System Saves Steps and Is Safer for Techs
PET Agent Appears Promising for Evaluation of CAD
Cardiac Imaging: SPECT Versus PET
New CZT SPECT Camera Offers Faster Throughput
Auto-injection System Saves Steps and Is Safer for Techs
Auto-injection systems that deliver contrast agents and other fluids for CT and MRI exams are fairly common in modern hospitals, but the same kind of technology is less common for molecular imaging modalities. As a result, hospitals that offer FDG PET imaging have a complex and repetitive manual dosing and infusion protocol that is designed not only to administer a safe and accurate dose to patients, but also to reduce the radiation exposure to technologists and other laboratory staff.
A recent alternative to manual FDG PET infusion protocols is a molecular imaging auto-injection system developed by MEDRAD, Warrendale, Pa. Rather than individually prepare, measure, and safely transfer the FDG dose from the hot lab to the infusion room for each PET exam, MEDRAD’s Intego PET infusion system enables technologists to administer multiple FDG doses from an automated bulk infusion system.
MEDRAD?s Intego PET infusion system allows technologists to administer multiple FDG doses from an automated bulk infusion system.
Cedars-Sinai Medical Center in Los Angeles is one of the early adopters of the Intego system. Paula Barondess, CNMT, a veteran fusion technologist at the hospital, said that the Intego system has not only been as accurate as her previous manual protocols, but it has reduced her radiation exposure and potential for back injury.
“Before the Intego system, we were doing individual doses, anywhere from 13 to 16 per day. That was physically demanding and greatly increased our radiation exposure,” said Barondess.
Darrell Mack, CNMT, manager of nuclear medicine and research at Cedars-Sinai, explained, “Those individual doses had to be contained in tungsten pigs, which weigh almost 20 pounds. From a safety standpoint, that can be very tough on the technologist. Carrying these 20-pound blocks 15 times a day wears you out.”
Steps for the Intego system comprise a quality control check every morning, and then carrying and installing the 30-pound tungsten pig/FDG bulk dose to the Intego once a day, or perhaps twice, depending on the day’s volume. Once the Intego is ready, the technologist types in the patient’s name and weight, and performs the typical IV protocols before administration.
The Intego calculates the dose based on weight input, but the technologist can also adjust the amount, depending on the camera or doctor’s orders.
Measuring doses and assays, and carrying the pig back and forth from the hot room multiple times per day, are all eliminated. After the dose is administered, the Intego generates a printout at Cedars, but also has the potential to be integrated into hospital electronic health record systems.
Barondess estimated that Intego’s automated protocols are saving their PET unit 8 to 10 minutes per patient. At the same time, the self-contained bulk dose reduces the amount of radiation PET technologists are exposed to.
Additionally, Mack likes the fact that once the Intego is set up in the infusion room, the technologist can hook up the IV and stay with the patient, never having to retrieve the dose from the hot room or deliver the syringe back to the hot room after every infusion.
As department manager, Mack is also pleased for Intego’s potential to reduce technologist sick days. “The big advantage is that we don’t have any of the injuries we used to have related to the back strain. That’s huge for us here, because the technologist isn’t spending time out due to injuries related to repetitive lifting.”
While an automated FDG infusion system is an additional cost, Mack maintained that its advantages are justified in technologist safety from reduced radiation exposure, improved productivity, and better patient care.
?Tor Valenza
PET Agent Appears Promising for Evaluation of CAD
SPECT (single photon emission computed tomography) is today?s most widely used noninvasive diagnostic procedure in the evaluation of patients with suspected coronary artery disease. ?Currently, in the United States, there are about 7 million SPECT procedures done each year,? estimates David Pendleton, senior director of PET imaging for Lantheus Medical Imaging Inc, North Billerica, Mass, adding, ?SPECT is an excellent procedure and adds great value to patient management, but, of course, like any diagnostic procedure, it?s not perfect.?
David Pendleton
SPECT may sometimes yield false-positive or nondefinitive results and can miss multivessel disease. ?By contrast, PET myocardial perfusion imaging may be able to mitigate some or all of these shortcomings of SPECT imaging,? said Pendleton.
To maximize the clinical value of PET, Lantheus has a novel drug candidate in clinical development: flurpiridaz F 18, a PET perfusion imaging agent that targets mitochondrial complex 1. Early data from phase two trials of the drug are encouraging, and the company is preparing for the next phase of clinical research as it completes its full analysis of the phase two data set.
The Data
In the phase two trial, rest-stress flurpiridaz F 18 PET was compared to Tc-99m-labeled SPECT in the detection and evaluation of coronary artery disease in nine patients. Results were examined for specificity and sensitivity in the determination of the presence of coronary artery disease and the identification of diseased and normal arteries. The early results have been promising.
Jamshid Maddahi, MD, FACC, professor of molecular and medical pharmacology (nuclear medicine) and medicine (cardiology) at the David Geffen School of Medicine at the University of California Los Angeles, presented the data at the American College of Cardiology 59th Annual Scientific Session. The preliminary data presented indicate that PET myocardial perfusion imaging has a higher specificity for the identification of right coronary artery disease and the detection of more severe and extensive stress perfusion abnormalities in the territories of diseased coronary arteries.
The overall accuracy reported for the correct identification of diseased coronary arteries was 93% (25 of 27) for PET and 78% (21 of 27) for SPECT. In myocardial segments supplied by diseased coronary arteries, the summed severity score was significantly higher by PET than SPECT (16.3+9.3 vs 8.8+6.8, P <0.05), according to Maddahi.
The Promise
?The data are very preliminary?the study involved only nine patients?but they suggest that flurpiridaz F 18 may ultimately provide physicians with more accuracy and greater confidence in their evaluation of patients with suspected coronary artery disease. The procedure, ultimately, could be a great benefit to the cardiology and radiology professions,? said Pendleton, suggesting a link between data and outcome. In general, improved accuracy means improved data, which leads to improved decision making, which could result in an improved patient outcome.
To establish further evidence of the clinical value of PET myocardial perfusion imaging with flurpiridaz F 18, Lantheus plans to complete the broader phase two data analysis and initiate discussions with the FDA regarding a multicenter phase three study. The company hopes to begin enrollment in that study in the fourth quarter of this year.
?We still have a lot to learn about our agent, but the reaction of our investigators to this agent has been overwhelmingly positive. We?re extremely encouraged that flurpiridaz F 18 may ultimately add great value to patient management,? said Pendleton.
?Renee Diiulio
Cardiac Imaging: SPECT Versus PET
Patrick Rooney, CEO of Positron Corp, Fishers, Ind, states openly that he is not a clinician, but rather a chief executive officer who watches imaging market trends?especially trends that have to do with cardiac PET.
Attrius PET scanner from Positron.
Cardiac PET and its nuclear medicine accessories have been Positron?s main focus for the last 27 years. In fact, according to Rooney, Positron is in the unique position of being the only company in the world that offers a dedicated cardiac PET scanner to cardiologist practices. Many other companies offer hybrid PET/CTs, but not a dedicated cardiology unit.
In addition, the company recently received the Frost and Sullivan 2010 North American New Product Innovation Award for its Attrius PET scanner.
While awards and market exclusivity are great for any business, SPECT is still the bread and butter imaging choice for diagnostic cardiology imaging. However, Rooney believes that several factors are making cardiac PET imaging an attractive alternative for hospitals now. Axis Imaging News recently interviewed Rooney about these factors.
IE: Describe the markets for PET and SPECT cardiology over the last 5 years. What?s changed?
Rooney: In the past, cardiac PET has often been compared to SPECT, which is really the standard of care right now. There are about 14,000 SPECT cameras in the United States today, and about 140 dedicated PET cameras.
IE: Why do you think hospitals are taking more of an interest in dedicated cardiac PET? What?s changed?
Rooney: First, on October 30, 2009, CMS increased reimbursement for PET imaging by 25% and decreased SPECT imaging by 36% for cardiology. The reimbursement difference between imaging with PET versus SPECT is now approximately $1,000 to $1,200, depending on where you are and what?s covered in various states and regions. So, physicians will receive $1,000 to $1,200 more for imaging with PET, which makes PET financially more attractive.
Second, in the past, PET systems were very expensive, and reimbursement was comparable to that for a SPECT camera. A SPECT camera cost about $200,000 and a PET camera costs about $1.5 million, so not many practices would buy something for $1.5 million to make the same amount of money that you can make if you could image with the $200,000 camera. Positron has come out with an economical price PET scanner that is now listed below a million dollars.
Third, the primary radiopharmaceutical for cardiac PET imaging is rubidium, and the availability and industrywide acceptability of rubidium is much greater now than in the past.
IE: How has the Mo-99 (?Molly?) shortage affected the demand?
Rooney: Yes, that?s put a great deal of strain on SPECT cardiology practices. With SPECT radiopharmaceutical shortages affecting nearly every practice, there has been a significant shift from SPECT to PET, and cardiac PET is gaining even greater demand because of the Molly crisis. Even without the shortage, we have had stronger demand because of the other factors, but the Molly crisis has made people look at PET even more closely
IE: What about the return on investment (ROI) for PET? As you said, prices have come down, but you?re still paying a lot more for PET.
Rooney: In terms of ROI, as we discussed, there is the increase in CMS reimbursement, and typically the private payors will follow suit. From large hospitals to average volume practices, the ROI will always depend on volume. But quite frankly, we have a number of cardiologist practices that have probably paid for their scanners in 2 to 3 months.
IE: How do you calculate that?
Rooney: Think about it: If a practice is doing 10 SPECT exams a day, 20 days a month, that?s 200 studies a month. With 200 studies a month, 2,400 studies a year, these are now reimbursed at approximately $1,000 more with PET versus SPECT, depending on your area. With 2,400 exams per year times $1,000, that?s $2.4 million more a year. Yes, PET costs more than a SPECT camera, but once again, there is a value to better medicine, hence the higher reimbursement.
?T. Valenza
New CZT SPECT Camera Offers Faster Throughput
For a little over a year, Mount Sinai Medical Center, New York, has been using the first commercially available supine CZT (cadmium zinc telluride) SPECT camera for myocardial perfusion imaging (MPI).
The new camera from Waukesha, Wis-based GE Healthcare is called the Discovery NM 530c cardiac camera. Milena J. Henzlova, MD, professor of medicine and director of nuclear cardiology at Mount Sinai Medical Center, not only has used the camera, but also is one of the authors of a forthcoming study comparing the CZT to the traditional SPECT camera.
Fifty-year-old NaI (sodium iodine) SPECT cameras have been the technology leader in SPECT cardiac imaging. While effective, traditional SPECT cameras have a slow throughput and, compared to CZT technology, use higher tracer doses for imaging. Of course, the most important aspect of any imaging modality is its diagnostic quality.
Milena J. Henzlova, MD (front, center), with colleagues from Mount Sinai Medical Center and their new Discovery NM 530c from GE Healthcare.
Evaluating the first commercial supine CZT camera in the United States, Henzlova and colleagues at Mount Sinai conducted a study that has just been accepted for publication in the Journal of Nuclear Cardiology.
The peer-reviewed study of a total of 717 patients is currently titled ?Reduced Isotope Dose with Rapid SPECT MPI Imaging: Initial Experience with a CZT SPECT Camera.? It concludes that the CZT technology significantly reduced radiation exposure while also substantially decreasing image acquisition time. Moreover, the study confirmed excellent image quality with a 57% lower isotope dose.
Henzlova explained, ?We blindly looked at the quality of the images, looking at different imaging times and different doses of the isotope. Even if you use the lowest dose, which is 50% less than the traditional dose, and reduce the imaging time to 2 or 3 minutes, the quality remains excellent.?
While not ideal for small cardiology practices, Henzlova said that the CZT?s extra cost can certainly be justified through higher throughput.
Speaking of Mount Sinai?s gamma SPECT cameras, Henzlova said, ?We used to image for 15 to 20 minutes. Now with the CZT camera, we can image in 2 to 4, or 3 to 5 minutes. That?s three times faster.?
She added that faster throughput can reduce needed personnel, cut down on technologist overtime, or even reduce the number of on-site cameras while achieving the same number of studies. Another advantage for a New York City-based medical center: a smaller footprint, freeing much needed square footage.
In addition, higher throughput and less radiation may also be a competitive advantage in a time when the media and the FDA are focused on reducing patients? exposure to ionizing radiation from medical imaging.
While the CZT technology has the aforementioned advantages, it also has some disadvantages. First, as with many imaging devices today, the platform is challenging for the morbidly obese. Second, and somewhat related, the camera does not currently have attenuation correction, which can produce artifacts when imaging obese patients or imaging through breast tissue in women.
Even so, Henzlova is confident that the camera?s advantages outweigh its disadvantages, especially with its potential to reduce patient exposure to radiation without sacrificing image quality.
?I would not go back,? she said. ?It?s much easier for the patients, the personnel love the camera because there?s much less downtime, and we?re pleased that we?re using low doses of the isotopes, while the image quality remains very good.?
?T. Valenza
