Accuracy of Half of the Usual Radiotracer Dose in SPECT (SPECT-Light)

February 23, 2016 updated by: Renee Hessian, Ottawa Heart Institute Research Corporation

Diagnostic and Prognostic Accuracy of Stress SPECT Myocardial Perfusion Imaging With Half the Usual Radiotracer Dose

There has been a shortage of nuclear isotopes, not only in Canada but around the world. New, more sensitive SPECT cameras can obtain better images in shorter scan times. These cameras have also shown the ability to use a smaller dose of radioisotope to obtain the images. New software has been tested on the standard camera, the GE Infinia-Hawkeye SPECT/CT. The Diagnostic Imaging Department of The University of Ottawa Heart Institute has also acquired a new camera, the Discovery NM530c CZT and has been doing heart scans in shorter times. The investigators will now be looking at the quality of images using less isotope during SPECT myocardial perfusion imaging for diagnostic and prognostic purposes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

SPECT MPI is well accepted as a reliable and cost-effective tool for diagnosis, risk stratification and management of patients with suspected or known coronary artery disease (CAD) (1;2). MPI represents approximately 40% of nuclear medicine patient studies and most of these use 99mTc-sestamibi or 99mTc-tetrofosmin(3). Rest/stress MPI using 99mTc-sestamibi and 99mTc-tetrofosmin uses more tracer doses than many other nuclear medicine tests and thus account for >50% of injected radiotracer activity(3). Thus, interruptions in the supply of 99Mo, the parent isotope of 99mTc, significantly affect stress MPI imaging and associated patient care.

Alternatives to 99mTc-sestamibi and 99mTc-tetrofosmin for perfusion imaging include 201Tl for SPECT imaging and 82Rb or 13NH3 for positron emission tomography (PET) imaging (4;5). MPI using 201Tl has similar diagnostic accuracy but image interpretation is more difficult due to greater scatter and attenuation. Moreover, the patient effective radiation dose for MPI using a standard injected dose of 3.5mCi of 201Tl is ~20 mSv. This radiation dose is twice that of 99mTc tracers which typically deliver an effective dose of ~10 mSv. PET imaging with 82Rb or 13NH3 is another alternative, but is much more expensive and not routinely available in Canada due to a very limited install base of PET scanners and associated cyclotrons. The number of SPECT cameras operational in Canada is more than 40 times the number of PET scanners.

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Ottawa, Ontario, Canada
        • University of Ottawa Heart Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Consecutive patients presenting for clinically indicated SPECT perfusion scan
  • Patients presenting to sites with a functional CZT camera. Available sites are Ottawa (OHI), Mississauga, and Calgary.
  • Age >18 years old

Exclusion Criteria:

  • Patients with a life expectancy less than 1 year, from non cardiac cause
  • Age < 18 years old or lack of consent
  • Allergy or contraindication to dipyridamole
  • Refractory angina or infarction or need for urgent angiography
  • Known pregnancy
  • Uncontrolled atrial fibrillation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Comparison of radioisotope dosing
Radiation: 1/2 dose of 99mTc OR 201Tl tracers

Rest: Imaging will occur 30 to 60 minutes after injection of tracer.

Stress: All patients will undergo a symptom-limited Bruce protocol treadmill exercise test. At peak stress, the radiotracer will be injected intravenously, and exercise will continue for an additional 60 s. The patients who are unable to achieve the targeted heart rate or exercise will be stressed pharmacologically. Dipyridamole (0.142 mg/kg/min) will be infused intravenously for 5 minutes, and 99mTc radiotracer will be injected at 2 min after infusion completion (7 min into the study). Aminophylline (100-200 mg) will be given intravenously 2 min after injection of the radiotracer.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of non-fatal infarction or death in the normal group of SPECT-Light acquisitions versus standard SPECT acquisitions
Time Frame: 2 years
The difference in the rate of non-fatal infarction or death that occurs in the normal group of the combined SPECT-Light acquisition protocols (LDa and LDb) versus the outcome that occurs in the acquisitions obtained by the standard SPECT (FD) protocol.
2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Comparison of classification of the degree of abnormality based on the two image acquisition protocols
Time Frame: 2 years

A comparison of classification of the degree of abnormality based on the two image acquisition protocols. Multi-level correlation between the two image sets (LDa vs 2 and LDb vs 2) will be obtained against the standard SPECT (FD) images.

The combined rates of non-fatal MI or death in each of the LD images as well as the standard dose images (FD) which are considered abnormal (SSS ≥ 4) will also be calculated.
2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ottawa Heart Institute Research Corporation

Investigators

  • Principal Investigator: Renée Hessian, MD, Ottawa Heart Institute Research Corporation

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2010

Primary Completion (Actual)

March 1, 2013

Study Completion (Actual)

September 1, 2014

Study Registration Dates

First Submitted

August 7, 2011

First Submitted That Met QC Criteria

August 8, 2011

First Posted (Estimate)

August 9, 2011

Study Record Updates

Last Update Posted (Estimate)

February 24, 2016

Last Update Submitted That Met QC Criteria

February 23, 2016

Last Verified

February 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HI Protocol #2010127-01H

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Coronary Artery Disease

Clinical Trials on 1/2 dose of 99mTc OR 201Tl tracers

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Armenia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe