What is positron emission tomography?

Positron emission tomography (PET) is a form of

nuclear medicine imaging. Using radioactively labelled

compounds (radiopharmaceuticals), PET produces images

that display the functioning of human organs. PET may

complement information obtained from anatomic imaging

methods, such as CT or MRI.

Why is PET important to VHA?

VHA has made a substantial resource committment to

PET. Since 1979, VHA has approved 12 PET centers, 10

of which are operational. PET is recognized as a valuable

basic research tool. The potential clinical diagnostic

applications of PET were the focus of an assessment by the

Management Decision and Research Center (MDRC).

Why was an assessment of PET conducted?

The MDRC Technology Assessment Program was

charged with conducting a rigorous assessment of PET to

assist the Under Secretary in planning VHA policy on PET.

The MDRC was asked to provide information on VHA’s

current uses of, and experience with PET, and to consider

whether VHA should establish additional PET centers.

Methods

The MDRC convened an Advisory Committee to focus

the assessment and to recommend policy decisions based on

the assessment findings.

The Committee identified several clinical conditions of

importance to veterans for which PET has potential

diagnostic applications:

• solitary pulmonary nodules;

• lung cancer;

• head and neck cancers;

• breast cancer;

• colorectal cancer; and

• Alzheimer’s disease.

The Committee restricted the scope of the assessment to

studies that used the most common radiopharmaceutical,

M A N A G E M E N T B R I E F

Number 6 June 1997

fluorodeoxyglucose (FDG), with PET as a diagnostic test in

the clinical management of these conditions.

Using explicit criteria and an analytic framework developed from principles of evidence-based medicine, the

MDRC conducted systematic reviews of research articles

published in peer-reviewed medical journals.

The MDRC also conducted surveys and site visits of

VHA PET centers to collect information on PET imaging

utilization, center operations, and research activities.

Highlights of the PET assessment

The MDRC found that research into the clinical utility

of PET for the selected conditions is in its preliminary

stages. Methodologic weaknesses in the published studies

seriously limit the validity and generalizablity of the available evidence on the accuracy of PET as a diagnostic test.

Few studies addressed changes in treatment decisions based

on PET findings. None of the studies identified by the

MDRC reported changes in the outcomes of care or the

cost of care that could be associated with the use of PET.

Based on these findings, the assessment team believes

that the literature, as of September, 1996, does not support

widespread incorporation of PET into routine diagnostic

strategies for the applications addressed in this assessment.

Alzheimer’s disease

Published studies using PET to diagnose Alzheimer’s

disease have been relatively well constructed. Diagnoses of

dementias of the Alzheimer’s type using PET correspond

closely to those made with widely used clinical criteria.

Studies in Europe are underway to define the agreement of

PET with the gold standard for diagnosis of Alzheimer’s

disease (examination of brain tissue on autopsy). However,

several compelling reasons argue for continued use of PET

primarily as a research tool. These reasons include:

• lack of valid estimates of the positive predictive value of

PET,

• parallel developments in other tests, and

• the limited treatment options for Alzheimer’s disease.

Created by the Management Decision & Research Center, HSR&D, Office of Research & Development.

Positron Emission Tomography: The VHA PET Experience
Selected cancers

The published evidence for the accuracy of PET in

diagnosing cancer is less convincing. Many studies did not

adhere to established principles of study design and tended

to overestimate the accuracy and clinical value of PET. The

lack of epidemiologic information in these studies is a

critical obstacle in VHA’s efforts to rationalize service

provision on a regional or system-wide basis. This shortcoming makes extrapolation of study results to defined

populations, and subsequent planning for these populations,

difficult.

FDA compliance

The FDA has approved two PET radiopharmaceuticals

for limited use in PET scanning. FDA regulations state

that PET centers which manufacture radiopharmaceuticals

and clinical investigators who wish to conduct clinical trials

with an unapproved PET radiopharmaceutical must

proceed under the aegis of federal (not state) regulations.

The FDA has offered to work with the PET community to

help sponsors and investigators interpret and follow the

appropriate regulations.

Site visits

The site visits and surveys confirm that VHA has made a

substantial resource commitment to its PET imaging

facilities. VHA researchers who were interviewed for this

assessment widely credited PET as an important basic

research tool. Several suggestions were offered to improve

the efficiency of basic research activities and PET center

operations. Site investigators identified a wide range of

research and clinical activities in VHA PET centers, but

noted that these activities remain largely uncoordinated.

Recommendations

The Advisory Committee concurred with the results of

the assessment and supported the conclusion that VHA

should not invest in additional PET centers at the present

time. Rather, VHA should maximize the value of its

existing commitment, which could include:

• Implementing a VHA PET registry for collecting

systematic, standardized data and for tracking the utility

of PET in selected conditions.

• Coordinating efforts by VHA PET centers and their

academic affiliates to comply with FDA regulations to

identify clinical research areas of interest to VHA, and

to design multi-center studies of high methodologic

quality.

• Supporting rigorous, prospectively designed clinical

research that expands the body of PET literature in a

manner that is methodologically sound.

• Submitting currently unpublished data from studies of

high methodologic quality for peer review.

Implementation of recommendations

The recommendations in the VHA PET assessment

were reviewed and approved by the Under Secretary, and

will be implemented through the Office of Patient Care

Services. Dr. John Booss, the field-based Director of

Neurology, has been appointed to facilitate the process.

The “PET Action Plan Group,” which includes VHA PET

Center Directors, will coordinate the activities of PET

facilities throughout the VHA system, with some central

oversight and assistance. Initially, the Group’s primary

focus will be to establish a PET registry and to coordinate

relations with the FDA. The Group will meet on July 1 at

Headquarters to finalize plans for the registry and to discuss

clinical topics for which multi-center studies could be

conducted.

The VHA PET community has a unique opportunity to

improve the quality and content of its scientific base, and to

provide sound, valid evidence on which to base future

decisions regarding the role of PET in improving health

care to veterans and to the general population.

How to get the PET report

• Request a copy through your local VAMC library.

• Download an electronic copy in PDF format on the VA

intranet (http://152.128.2.7/mdrc) or from the VA home

page (http://www.va.gov/mdrc).

• Order a copy from the NTIS by calling 800-553-6847

and asking for publication # PB97-143614 (paper copies,

code A14) $49.00, (microfiche copies, code A03), $19.50.

REFERENCE

Management Decision and Research Center Technology Assessment Program. Positron emission tomography: descriptive analysis of

experience with PET in VA and systematic reviews: FDG-PET as a

diagnostic test for cancer and Alzheimer’s disease. October, 1996.

Veterans Health Administration. Department of Veterans Affairs:

Washington, D.C.

M A N A G E M E N T B R I E F Number 6, June 1997, Page 2

This is our sixth MANAGEMENT BRIEF. Please give us your suggestions;

Topics for future BRIEFS: ___________________________________

______________________________________________________

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Comments on the MANAGEMENT BRIEF:

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Name: _________________________________________________

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Phone: ________________________ Fax: ____________________

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Please send me the MANAGEMENT BRIEF by: E-mail ___ or Fax ___

The MANAGEMENT BRIEF is produced by the Management Decision and

Research Center, a program within the VA’s Office of Research &

Development, Health Services Research and Development Service.

The purpose of the MANAGEMENT BRIEF is to provide VA senior

managers with a concise and timely overview of a specific health care

topic that includes topic definition, benefits, VA activities, and resources

for further information.

Please send comments to Gerry McGlynn, MDRC 152-M,

150 South Huntington Avenue, Boston, MA 02130. Or, by phone at,

FTS 700-839-4433 or COM 617-278-4433 FAX: 617-278-4438.
The MDRC Technology Assessment Program of the Health Services Research and Development

Service, Office of Research and Development, Veterans Health Administration, is pleased to

announce the release of the following technology assessment report:

Positron Emission Tomography:

n descriptive analysis of experience with PET in VA

n systematic reviews: FDG-PET as a diagnostic test

for cancer and Alzheimer’s disease

How to get the report:

Within VA:

• Download an electronic version (PDF) from the VA intranet at

http://152.128.2.7/mdrc or from the VA home page at http://www.va.gov/mdrc.

• Request a copy from your local VAMC library.

• Email us at g.mdrc-ta@forum.va.gov for other options.

Outside VA:

• Order hard copies or microfiche from the National Technical Information Service

(NTIS). Call customer service at 1-800-553-6847or 703-487-4660, ask for publication

# PB97-143614. Paper copies (publication code A14) are $49.00, microfiche

(publication code A03) are $19.50.

• Download an electronic version (PDF) from the VA home page on the world wide

web at http://www.va.gov/mdrc.

• Email us at g.mdrc-ta@forum.va.gov for other options.

MDRC (152M) • VA Medical Center • 150 So. Huntington Avenue, Boston, MA 02130 • Tel. 617-278-4469 FTS 839-4469 Fax 617-278-4438