By Keith Loria
Vol. 24 No. 7 P. 14
What it Takes to Become a Canadian Centre of Excellence in Molecular Imaging and Theranostics
St. Joseph’s Health Care London and the Lawson Health Research Institute in Ontario, Canada, will advance the blend of diagnostic imaging and targeted therapy for cancer and other diseases thanks to a new partnership with GE HealthCare. Through the joint venture, St. Joseph and Lawson will become Canada’s first ever Centre of Excellence in personalized treatment of cancer, known as molecular imaging and theranostics.
Narinder Paul, MD, FRCR, a scientist with Lawson Health Research Institute, chief of medical imaging at St. Joseph’s Health Care London, and chair of the department of medical imaging at Western University’s Schulich School of Medicine & Dentistry, explains that molecular imaging provides detailed imaging at the molecular level and theranostics combines therapeutics and diagnostics.
“Together, [molecular imaging and theranostics] is a two-pronged approach to diagnosing and treating cancers and other diseases that merges imaging with the use of radiotracers that can not only identify the location and extent of diseased tissues but also selectively destroy the abnormal cells while leaving surrounding healthy cells undamaged,” he says.
GE HealthCare will supply St. Joseph’s with its latest generation, state-of-the-art PET/CT, the Omni II, which will expand clinical care at St. Joseph’s by significantly enhancing research through the imaging research group at Lawson, working together with researchers at St. Joseph’s Health Care London, the London Regional Cancer Program, and Western University. The area that will be served encompasses about 2 million people. The new PET/CT replaces an aging machine that is in the process of being removed this fall. The new equipment is expected to be operational in October. It will serve about eight to 10 patients per day or 1,900 to 2,400 per year. The facility’s demographics for these services are largely cancer care related; however, neurology and cardiology are common components of PET/CT programs as well.
“We will leverage the combined scientific expertise and innovation of scientists from GE HealthCare and Lawson to maximize the future opportunities of molecular imaging theranostics made possible through PET/CT imaging and be leaders in Canada in this area of medical science,” says David Hill, MD, scientific director at Lawson.
The PET/CT programs in London— which include St. Joseph’s Health Care London and London Health Sciences Centre—support the southwest region. The next closest PET/CT scanners are in Windsor, Hamilton, and the greater Toronto area.
“A personalized approach to medical care requires a highly detailed understanding of the localization of disease and potential response to different treatment options,” Paul says. “We will be able to offer patients across our region access to the latest therapeutic options based on a deeper understanding of the nature of their individual disease conditions gained through next-generation medical imaging.”
Defining Centre of Excellence
In Paul’s assessment, there are four academic pillars for becoming a Centre of Excellence.
“The most important of which is clinical excellence, doing the very best for the patients who come to you,” he says. “But we also know that in our clinical field, there’s a gap between what we’d like to do and what we can do. And to address that gap, you have to do research innovation.”
A third pillar is education—teaching people how to do the new techniques that you’ve validated so that doctors, nurses, scientists, or other clinicians can learn from what is done and then take that to another center across Canada or the world so they can disseminate the learnings and positively impact more people.
“The fourth pillar is outcomes or advocacy,” Paul says. “In a dual role, you want to make sure that if you’ve improved the way one patient experiences health care, or a certain subsubsection of the population has an improvement, has that really shifted the health curve for the population as a whole? That’s the outcomes piece. If we have made a difference in society, then we have to advocate for the appropriate resources from the government and the appropriate technology for industry partners.”
A Centre of Excellence, he notes, must embody all of these qualities to move the dial for the region and country.
Molecular imaging is different, Paul adds, because it is done by injecting compounds that are taken up by the body and distributed throughout the body. The most common use of PET/CT is mainly for cancer and response to treatment.
“In PET/CT, we inject glucose into the body, and the glucose is taken up by that body anywhere the cells are hungry for glucose, for example, in tumors or infection,” Paul says. “And to that glucose, we add a radioisotope which shows up on our PET/CT. It’s fundamentally different from radiology because it’s really a functional imaging exam.”
Going further, theranostics is a combination of diagnosis and treatment, where physicians can inject a radioisotope that treats the cancer.
“If you have a patient and you take a particular part of their body that has a cancer cell, and it’s surrounded by normal cells, for example, the liver, the difference between the cancer cells and the liver cells is that on the surface of the liver cells, there are abnormal proteins that you can identify as cancer cells. The liver cells do not have those abnormal proteins,” Paul explains. “You can develop proteins that will recognize just the abnormal proteins on the cancer cells and no other proteins in the body. And to that molecule, you can attach a radioisotope that you can pick up on your PET/CT or imaging equipment. So you inject that, and that molecule will only attach itself to a cancer cell, and the radioisotope that’s attached to it will show up on a detector, so now you know where all the disease is.”
The second part of the process takes the same molecule that recognizes only the cancer cells and attaches another radioisotope that is not for diagnosis but for treatment. It’s a lot stronger in terms of radiation, but it doesn’t travel as far. When the molecule is injected, it will go into the same cancer cell that was seen on the diagnostic scan and kill it locally.
“Now, if you’ve got somebody who’s got a lot of disease all over their body, this treatment will just go to just where the cancer is, and it should leave everything else alone,” Paul says. “We’ve seen some amazing results, for example, in patients with stage four prostate cancer that was resistant to standard treatment. And there are many more of these molecules and therapies being developed.”
Unfortunately, there are not many theranostic agents available right now, although many companies are developing them. “You can see why it’s so exciting. For many people who have early-stage cancer, is surgery often a good option? For people who have locally advanced disease, local chemo may be the right thing to do. If the disease has spread all over the body, there are some chemotherapies that are highly effective, but there are some that have significant side effects. In those cases, physicians can never give a big enough dose to treat the patient because the patient gets too sick with the chemo,” Paul says. “The hope is, if you can do theranostics, which just targets the cancer cells, you can treat the cells, and the patient won’t have the side effects that they would have from other therapies.”
In order to be successful with theranostics, a hospital or health system needs a complete science lab to provide the infrastructure that will support the molecular chemist or engineer who designs the molecule. A radio chemist, who will attach the molecule to the radioisotope, is also needed. The imaging equipment and the lab where this work is done is perhaps the most important aspect of this infrastructure, and none of it is inexpensive.
“The wonderful thing about St. Joe’s and the Imaging Research Center within St. Joe’s is that, for many decades, we’ve invested in a great deal of infrastructure for this,” Paul says. “We can make various radioisotope compounds. We’ve got a range of chemistry labs, which will need to be expanded, but our foundation has been really good at raising money to expand, and you need space for the scientists. We’ve invested heavily in all of that.”
St. Joseph’s Health Care London also has a strong clinical program, which is across the city in the London Regional Cancer Center. It also has strong links to the university where the probes are developed.
“For the longest time, we’ve had pieces of the jigsaw, and we’re now bringing it together as a theranostics program, thanks to the Omni II,” Paul says. One of the reasons St. Joseph’s chose the Omni II is a longstanding relationship with GE. The biggest factor, however, is the machine’s capacity to scale up.
“It has many useful features, one of which is the detector, which is 30 cm,” Paul says. “That’s important because it can be upgraded in-field with similar detector rings—up to four—so you can eventually have 1.2 meters.” That is crucial, he says, because the radioisotope decays over time after it is injected. Some radioisotopes are extremely short-lived.
“So if I knew an exam was going to take 45 minutes, I would have to inject enough radioisotope to make sure that by the time I get to imaging the legs, there is still enough in the body to give me an image. For this reason, I have to inject more than I would if I were scanning only the head to allow enough time,” Paul says. “But if the detector itself is twice the length of the current detector, you can get twice as many counts in the same amount of time. This allows you to inject half the compound. You can also double the speed of the exam.”
A large component of the PET/CT machine’s use—up to 80%—will be research and innovation, supporting both academic and clinical trials.
St. Joseph’s investment in cutting-edge technology bodes well for the future. Paul credits the foresight that the organization’s leaders had to invest in the field.
“It takes a lot of vision, it takes a lot of dedication, and it takes putting your money where your mouth is,” Paul says. “St. Joe’s has situated itself in a good position because of past investments and ongoing investment.”
— Keith Loria is a freelance writer based in Oakton, Virginia. He is a frequent contributor to Radiology Today.