The history of cerebral PET scanning: from physiology to cutting-edge technology

OBJECTIVE

To review the discoveries underpinning the introduction of cerebral PET scanning and highlight its modern applications.

BACKGROUND

Important discoveries in neurophysiology, brain metabolism, and radiotracer development in the post-World War II period provided the necessary infrastructure for the first cerebral PET scan.

METHODS

A complete review of the literature was undertaken to search for primary and secondary sources on the history of PET imaging. Searches were performed in PubMed, Google Scholar, and select individual journal Web sites. Written autobiographies were obtained through the Society for Neuroscience Web site at www.sfn.org. A reference book on the history of radiology, Naked to the Bone, was reviewed to corroborate facts and to locate references. The references listed in all the articles and books obtained were reviewed.

RESULTS

The neurophysiologic sciences required to build cerebral PET imaging date back to 1878. The last 60 years have produced an evolution of technological advancements in brain metabolism and radiotracer development. These advancements facilitated the development of modern cerebral PET imaging. Several key scientists were involved in critical discoveries and among them were Angelo Mosso, Charles Roy, Charles Sherrington, John Fulton, Seymour Kety, Louis Sokoloff, David E. Kuhl, Gordon L. Brownell, Michael Ter-Pogossian, Michael Phelps, and Edward Hoffman.

CONCLUSIONS

Neurophysiology, metabolism, and radiotracer development in the postwar era synergized the development of the technology necessary for cerebral PET scanning. Continued use of PET in clinical trials and current developments in PET-CT/MRI hybrids has led to advancement in diagnosis, management, and treatment of neurologic disorders.

[Operative neurosurgery: Personal view and historical backgrounds. (10) Microneurosurgery and PET scan: clinical experience of a neurosurgeon]

During the author's clinical activity at three institutes : Kyoto University Hospital (Kyoto 1965-1969, 1977-1985), National Cardiovascular Center NCVC (Osaka 1986-1992) and Zurich University Hospital (Zurich 1970-1976, 1993-2007), He has experienced (underlined periods) working with PET scan and SPECT in relation to microsurgical treatment. The following describes how and for what the author has been engaged in this regard. 1. As preparation for the work with PET, SPECT with a rotating gamma camera was used to know blood distribution with the use of Kr-81m infusion from a selectively located catheter in the ICA, ECA or VA, e.g. to know the flow distribution of a newly constructed EC-IC bypass, which was quite separated from and not mixed up with that of already functioning inherent collaterals (Fig. 1). 2. With the use of inhalation PET scan (15O labelled CO2 and O2 inhalation and 15O CO inhalation) basic knowledge of hemodynamics of MMD was acquired (Fig. 2) 3. With the use of H215 O-PET scan with DiamoxR loading, indication for and effectiveness of EC-IC bypass surgery for occlusive cerebrovascular disease (atherosclerosis (anterior circulation (Fig. 5), posterior circulation (Fig. 6, 7)), MMD (Fig. 9), congenital disease (Fig. 8) have been settled or demonstrated. 4. In epileptic seizures, interictally or intraictally, the active locus has been identified by the use of FDG-PET, flumazenil-PET, H 2 15 O or 13 NH 3-PET respectively (Fig. 12). In this relation, selective Wada test with the use of Tc-99 m-ECD selective infusion together with Amytal R through a catheter inserted selectively into the anterior choroidal artery is an important preoperative test for the SAHE (Fig. 13). 5. FDG-PET and/or tyrosine PET supply important clues concerning appropriate surgical treatment strategy, and also for intractable glioblastoma or high grade glioma, so that in combination with radiotherapy and chemotherapy one may expect more excellent long term outcome with good quality of life (Fig. 16, 17). Furthermore, there must be cases with dementia in which some revascularization procedure might be of help, for which FDG-and H 2 15O-PET could be helpful for differential diagnosis and indication of surgery (Fig. 18).

The emergence of diagnostic imaging technologies in breast cancer: discovery, regulatory approval, reimbursement, and adoption in clinical guidelines

In this article, we trace the chronology of developments in breast imaging technologies that are used for diagnosis and staging of breast cancer, including mammography, ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography. We explore factors that affected clinical acceptance and utilization of these technologies from discovery to clinical use, including milestones in peer-reviewed publication, US Food and Drug Administration approval, reimbursement by payers, and adoption into clinical guidelines. The factors driving utilization of new imaging technologies are mainly driven by regulatory approval and reimbursement by payers rather than evidence that they provide benefits to patients. Comparative effectiveness research can serve as a useful tool to investigate whether these imaging modalities provide information that improves patient outcomes in real-world settings.

Sacred radical of psychiatry

At least a dozen articles in this journal have referred directly to the psychiatry of Thomas Szasz, even favourably on occasions. Szasz makes no distinction between the occupational statuses of mental health workers and so his work is relevant to nurses. Szasz's central claims take on renewed vitality given recent developments in forensic care, especially in Britain. In this article, I criticize Szasz's rationale of what constitutes illness as opposed to disease. In addition, I question - in a nuanced way - his views on custodial psychiatry and his use of history to bolster his clams. I also comment on recent developments in biological research and their implications for diagnosing schizophrenia: further, I link the question of such diagnoses to Szasz's assertion that private contracts are the definitive test of what counts as mental illness. Lastly, I ask if improvements in mental health care contradict Szaszian criticisms and/or his seeming inability/unwillingness to acknowledge such changes.

The contribution of medical physicists and doctors in Aberdeen to the evolution of modern medical imaging--SPECT, PET and MRI, 1965-1992

From the beginnings of medical imaging with radioactivity, an account is given of the development in Aberdeen of Computed Tomography (CT) scanners in Nuclear Medicine, and their clinical value, leading to present-day gamma-cameras. The introduction and clinical use of the cyclotron and Positron Emission Tomography (PET) imager in Aberdeen, has led to a national programme for the cancer patients in Scotland. Early animal work with electron magnetic resonance, which developed into a programme towards nuclear magnetic resonance of water, and then to a quest to build the first clinically-useful whole-body MRI, is described. Successful diagnostic images obtained with it have led to the present-day worldwide use of the MRI technique.

[PET in Aarhus: the origins of a laboratory]

Recent medical history is a new trend among medical historians. The new focus on late developments of note to health care providers has inspired me to relate certain personal events related to the establishment of a laboratory of positron emission tomography in a remote city of a small country far away. The record may be appropriate because the laboratory celebrated its 10th anniversary in 2003. The laboratory is the home of an advanced technology with special needs in terms of space, installations and staff. The technology rests on a combination of random discoveries and goal-directed inventions that include the discovery of positrons, the invention of the cyclotron, the development of computerized analysis of huge data sets, insight into the biochemistry of organs and the quest for understanding of the pathology of specific diseases. U.S. researchers played unique roles in the three former areas, while Danish researchers made important contributions to the latter two areas.

A brief history of cell labelling

The term cell labelling is usually used in the context of labelled leukocytes for imaging inflammation and labelled platelets for imaging thrombosis. Erythrocyte labelling for in vitro measurements of red cell life span, in vivo measurements of splenic red cell pooling, radionuclide ventriculography and imaging sites of bleeding has developed rather separately and has a different history. Labelled platelets and leukocytes were originally developed for cell kinetic studies. Since the current-day applications of labelled platelets and leukocytes depend on a clear understanding of cell kinetics, these classical studies are important and relevant to the history of cell labelling.

From 3-D positron emission tomography to 3-D positron emission tomography/computed tomography: what did we learn?

The recent introduction of combined positron emission tomography (PET)/computed tomography (CT) scanners is having a far-reaching effect on the field of medical imaging by bringing functional imaging to the forefront in radiology, oncology and other specialties. The PET/CT scanner is an evolution in technology combining two well-developed imaging modalities: anatomical imaging with CT and functional imaging with PET. The first prototype PET/CT scanner was a consequence of a succession of steps that, in chronological order, included the development of the High Density Avalanche Chamber (HIDAC) PET camera, 3-D PET methodology and the rotating partial-ring tomograph (PRT). The successful completion of each step was a prerequisite to progress to the next phase, and the lessons learned could then be applied to subsequent initiatives. This review will map the milestones from 3-D PET to 3-D PET/CT and assess the role each step played in the development of PET instrumentation over the past two decades.