Greg Freiherr, Industry Consultant

Greg Freiherr has reported on developments in radiology since 1983. He runs the consulting service, The Freiherr Group.

Blog | Greg Freiherr, Industry Consultant | July 21, 2011

Positron Imaging and the Future of Radiology

Wielding an assortment of high-energy photons, ultrasonic waves and radiofrequencies, radiology has made a practice of peeling back virtual tissue to guide the management of patients. Positron emission tomography (PET) is the ultimate expression of this and an example of what radiology must do to succeed.

With PET you can see cellular function to differentiate healthy from cancerous cells; determine the viability of heart tissue; document if a drug is having the desired effect.

No, it’s not perfect. Its hybridization with computed tomography (CT) attests to this. PET’s recent alliance with magnetic resonance (MR) underscores its shortcomings. But it also reveals PET’s strengths. The ability to hybridize, to overcome weakness, makes it an example of what radiology must become in the future.

By design, PET combines with best-of-breed technologies to go beyond the state-of-the-art; the whole becoming greater than the sum of the parts; one part stepping in to capitalize on specific opportunities.

Pundits believe PET/CT will remain the procedure of choice for staging and following up cancers well characterized by CT. It will likely continue as the best way to monitor patient response to some treatments.  But PET/MR is being suggested for cases where MR is inherently better than CT. Already the groundwork for future clinical applications is taking shape, buoyed by peer-reviewed research done on prototypes.

• PET/MR may be more sensitive than PET/CT at detecting liver metastases. (Donati OF, Hany TF, Reiner CS, et.al. Value of retrospective fusion of PET and MR images in detection of hepatic metastases: comparison with 18F-FDG PET/CT and Gd-EOB-DTPA-enhanced MRI. J Nucl Med. 2010 May; 51(5):692-9. Epub 2010 Apr 15.)

• The ability of MRI to visualize the hemodynamics of gliomas combined with PET’s ability to interrogate glioma physiology could provide an early indicator of tumor response to therapy, particularly when antiangiogenic agents are involved. (Gerstner ER, Sorensen AG, Jain RK, et.al. Advances in neuroimaging techniques for the evaluation of tumor growth, vascular permeability and angiogenesis in gliomas, Curr Opin Neurol. 2008 Dec; 21(6):728-35.)

• Diffusion tensor imaging with simultaneous PET may help in the treatment planning of patients with brain tumors. (Boss A, Kolb A, Hofmann M, et.al. Diffusion tensor imaging in a human PET/MR hybrid system. Invest Radiol. 2010 May; 45(5):270-4.)

A year ago, disruptions in the supply of technetium, the backbone of single photon emission computed tomography (SPECT), had undercut conventional nuclear medicine, causing some to promote PET/CT in its place, if for no other reason than the certainty of its radioisotope supply. Suddenly, with the unveiling at RSNA 2010 by Siemens and Philips of integrated PET/MR scanners, the equation changed. Now the advocates of PET talk about teaming with MR in cardiovascular imaging to go beyond what can be achieved with conventional nuclear cardiology, citing published research that shows combining PET and cardiac MR might enable the detection and differentiation of vulnerable plaques in the coronaries.  (Pichler BJ , Kolb A , Nägele T, PET/MRI: Paving the Way for the Next Generation of Clinical Multimodality Imaging Applications. J Nucl Med 2010 March 51(3) 333-336.)

It is this potential to recombine, adapt and overcome challenges and, thereby,  go beyond current capabilities that spurs the optimism of PET advocates. The evaluation of degenerative diseases, infections, inflammation and metabolic diseases are among the possibilities that lie ahead for PET – and illuminate the future of radiology.

Related Content

Indeterminate lesion on PET/CT classified by PET/MRI for 53-y-old man with lung cancer.

Indeterminate lesion on PET/CT classified by PET/MRI for 53-y-old man with lung cancer. Contrast-enhanced CT (A), PET (B), and fused 18F-FDG PET/CT (C) images are displayed in comparison with contrast-enhanced T1-weighted MRI (D), PET, and fused 18F-FDG PET/MRI (F) images. In CT (A), hyperdense, subcentimeter liver lesion (arrows) in segment VII is suggestive of transient hepatic attenuation difference or small hemangioma. As malignancy cannot be excluded, it needs further investigation. On PET/MRI, lesion is clearly classified as metastasis because of contrast enhancement and tracer uptake due to later acquisition time point. Follow-up CT confirmed diagnosis after 78 d. Images created by Ole Martin, University Dusseldorf, Medical Faculty and Benedikt Schaarschmidt, University Hospital Essen.

News | PET-MRI | September 18, 2020
September 18, 2020 — A single-center observational study of more than 1,000 oncological examinations has demonstrated
HABLE study prioritizes brain imaging and biomarker research among Mexican Americans.

Getty Images

News | PET Imaging | September 14, 2020
September 14, 2020 — To meet the pressing need to better understand the prevalence, progression, and clinical impact
A 12-year-long collaboration with Canon Medical Research USA, Canon Medical Systems Japan and Southern Nevada outpatient radiology leader Steinberg Diagnostic Medical Imaging (SDMI) has resulted in the development of 3 PET scanners, each generation more advanced than the last
News | PET-CT | September 08, 2020
September 8, 2020 — A 12-year-long collaboration with...
a) Includes scintigraphy and PET with and without concomitant CT. b) Includes conventional radiography, dual-energy x-ray absorptiometry, fluoroscopy, and radiography performed during radiologic interventions. c) Includes general, cardiothoracic, maxillary, plastic, and orthopedic surgery and neurosurgery. d) Includes allergology, cardiology, geriatrics, general internal medicine, pulmonology, gastroenterology, and rheumatology

a) Includes scintigraphy and PET with and without concomitant CT. b) Includes conventional radiography, dual-energy x-ray absorptiometry, fluoroscopy, and radiography performed during radiologic interventions. c) Includes general, cardiothoracic, maxillary, plastic, and orthopedic surgery and neurosurgery. d) Includes allergology, cardiology, geriatrics, general internal medicine, pulmonology, gastroenterology, and rheumatology. Image courtesy of American Roentgen Ray Society (ARRS), American Journal of Roentgenology (AJR)

News | Radiology Imaging | August 14, 2020
August 14, 2020 — According to ARRS' ...
In I-131 cancer therapy, decay events damage sensitive DNA within a tumor cell nucleus, causing catastrophic single and double strand breaks. Clinical use of antibody-delivered Auger emitters could open a window for the targeted destruction of extracellular COVID-19 virions, decreasing the viral load during active infection and potentially easing the disease burden for a patient. View all figures from this study.  http://jnm.snmjournals.org/content/early/2020/07/16/jnumed.120.249748.full.pdf+html

In I-131 cancer therapy, decay events damage sensitive DNA within a tumor cell nucleus, causing catastrophic single and double strand breaks. Clinical use of antibody-delivered Auger emitters could open a window for the targeted destruction of extracellular COVID-19 virions, decreasing the viral load during active infection and potentially easing the disease burden for a patient. View all figures from this study.

 

News | Coronavirus (COVID-19) | July 22, 2020 | Dave Fornell, Editor
July 22, 2020 — One of the first studies has been published that looks at the use of...
Tau (blue) and amyloid (orange) distribution patterns for super-agers, normal-agers and MCI patients, when compared to a group of younger, healthy, cognitively normal, amyloid-negative individuals. Brain projections are depicted at an uncorrected significance level of p < .0001. Color bars represent the respective t-statistic. Image courtesy of Merle C. Hoenig, Institute for Neuroscience and Medicine II - Molecular Organization of the Brain, Research Center Juelich, Juelich, Germany, and Department of Nucle

Tau (blue) and amyloid (orange) distribution patterns for super-agers, normal-agers and MCI patients, when compared to a group of younger, healthy, cognitively normal, amyloid-negative individuals. Brain projections are depicted at an uncorrected significance level of p < .0001. Color bars represent the respective t-statistic. Image courtesy of Merle C. Hoenig, Institute for Neuroscience and Medicine II - Molecular Organization of the Brain, Research Center Juelich, Juelich, Germany, and Department of Nuclear Medicine, University Hospital Cologne, Cologne, Germany.

News | PET Imaging | July 16, 2020
July 16, 2020 — Super-agers, or individuals whose cognitive skills are above the norm even at an advanced age, have b
PSMA PET/CT accurately detects recurrent prostate cancer in 67-year-old man. 18F-DCFPyL-PSMA PET/CT shows extensive, intensely PSMA-avid local recurrence in prostate (bottom row; solid arrow) in keeping with the known tumor recurrence in the prostate. Right: PET shows extensive, intensely PSMA-avid local recurrence in prostate (top row; solid arrow) and a solitary bone metastasis in left rib 2 (bottom row; dotted arrow). Image courtesy of Ur Metser, et al.

PSMA PET/CT accurately detects recurrent prostate cancer in 67-year-old man. 18F-DCFPyL-PSMA PET/CT shows extensive, intensely PSMA-avid local recurrence in prostate (bottom row; solid arrow) in keeping with the known tumor recurrence in the prostate. Right: PET shows extensive, intensely PSMA-avid local recurrence in prostate (top row; solid arrow) and a solitary bone metastasis in left rib 2 (bottom row; dotted arrow). Image courtesy of Ur Metser, et al.

News | PET-CT | July 16, 2020
July 16, 2020 — New research confirms the high impact of...