6 key trends in medical imaging physics
Medical physics plays a large role in radiology and is one of the subspecialty session tracts at the annual Radiological Society of North America meeting. Radiology Business spoke with American Association of Physicists in Medicine president-elect Mahadevappa Mahesh, PhD, professor of radiology and a medical physicist, Johns Hopkins University School of Medicine, who outlined six key areas of interest discussed at RSNA 2023.
He said these trends promise significant advancements in technology, quality control and patient safety.
1. Photon-counting CT takes the spotlight
The emergence of photon-counting computed tomography technology is a major focus, with various vendors entering the market. Mahesh said Siemens has been in this space for two years and expressed excitement about Philips, GE and others also offering their own systems. However, the importance of understanding the medical physics aspect of this new technology and its applications is emphasized, especially as new vendors work toward U.S. FDA approval.
"The major trend is the photon-counting CT in front of the diagnostic. There are a number of sessions going on on the photon counting, plus there's also an excitement now that there are other vendors on the verge of bringing their photon-counting systems to market," Mahesh explained.
2. Cone-beam CT quality control
Cone-beam CT is now used in cath lab angiography systems, surgical C-arms, dental imaging, breast imaging and radiation therapy. Mahesh stressed the need for continuous optimization of CBCT protocols, particularly in radiation therapy, where AI-driven adaptive therapy relies on CBCT for recalculating doses based on anatomical changes.
There is a growing need for more quality control oversight of CBCT technology, Mahesh said, which is rapidly expanding and is often a technology embedded as a secondary imaging capability of an X-ray system. He said there is a need to ensure the CBCT is calibrated separately from the main system to ensure top imaging quality and address dose concerns.
One of its most important uses of CBCT is for onboard imaging systems in radiation therapy. These imaging systems ensure perfect alignment of the patient on the treatment bed and the CT-scan based treatment plan. Newer radiation oncology systems also use CBCT for adaptive therapy, where AI will recalculate doses and the treatment plan based on changes in the anatomy that occurred since the last treatment session.
3. AI for dose reduction and image reconstruction
Artificial Intelligence is playing a pivotal role in reducing X-ray doses and enhancing image reconstruction. Mahesh acknowledged the challenge of AI being a "black box," emphasizing the need for physicists to understand and calibrate AI algorithms correctly to ensure reliable information for radiologists and technologists. This will also help AI gain wider acceptance in radiology with endorsements from their medical physicists.
"If an AI tool comes to the clinic, I need to know how to evaluate and understand it. AAPM is going to have a specialty AI bootcamp meeting this year before the annual meeting. The idea is to bring these experts who are doing AI research, and we as the auditors, together to talk about AI and for clinical medical physicists to learn about AI. That way we are able to bring back the feedback to our clinic," Mahesh said.
4. Theranostics in radiation oncology
The growing field of theranostics involves using targeted nuclear imaging radiotracers for simultaneous disease imaging and treatment. But while this trend offers personalized care that is tailored to each patient, it poses challenges for radiation physicists. Mahesh said they will need to determine optimal doses for each patient, which is much more involved than the current standard of radiation therapy dosimetry. Mahesh sees this as both a challenge and an exciting opportunity for the field with the creation of personal dosimetry physicists.
"At Johns Hopkins, one of our groups is very big in theranostics and they are even doing a clinical trial on using alpha particles. They have developed methodology to do the personal asymmetry on the research protocol and that has to be scaled up. But this gets a lot more intensive for calculation. So who will pay for that person? I personally feel it's a very exciting area, because there are a lot of groups working on different models for personal dosimetry. Which one will make the final cut? We do not know. But that's a very hot area to work on," Mahesh explained.
5. Fluoroscopy safety in focus
A dedicated effort is underway to address fluoroscopy imaging safety through a blue-ribbon panel involving AAPM and the American College of Radiology. Mahesh said the goal is to develop a curriculum tailored to different medical professionals, ensuring appropriate training hours based on their specific roles and procedures.
"So, a hand surgeon doing a simple procedure doesn't need 10 hours of fluoroscopy safety training. On the other hand, an interventional cardiologist who does a lot of it, he or she may need the hours," he said.
Mahesh is involved in the panel and they hope to create a detailed white paper on the subject later this year.
6. CT perfusion for cancer treatment assessments
CT perfusion is making a comeback, particularly in liver cancer treatment. It allows real-time monitoring of treatment effectiveness by quantifying changes in tumor size. The emphasis is on providing patients with a better understanding of treatment outcomes through regular follow-ups, Mahesh explained.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com