Reducing Radioisotope Dose: the Half-Dose CZT Study

The aim of this study is to compare the image quality of the half radioisotope dose scans
obtained using a CZT (cadmium zinc telluride) camera with scans acquired using a standard of
care imaging protocol/radioisotope dose performed on a traditional (conventional) camera.

The proposed strategy of a half dose/extended time protocol with the CZT camera should yield
a similar count activity and consequently image quality equivalent to that detected by a
conventional SPECT system.

Inclusion Criteria:

- ≥ 18 years of age and referred for a clinically-indicated stress SPECT MPI study

- suspected or known coronary artery disease

- written informed consent

Exclusion Criteria:

- Evidence of a normal baseline scan after at least 50% of the protocol acquired
baseline scans have been interpreted as being normal

- Participation in another investigational study within the preceding month

- Pregnant and/or breast-feeding female

- ECG evidence of left bundle branch block or paced rhythm

- Evidence of non-ischemic cardiomyopathy

- Presence of hypertrophic cardiomyopathy and/or severe valvular heart disease

- Severe claustrophobia or inability to lie flat for 20 minutes (the anticipated amount
of time to complete the procedure)

- Known allergy to technetium-99m

- Potential contraindications to regadenoson use, due to severe lung disease; severe
bradycardia (heart rate < 40 beats/min); second- or third degree atrioventricular
heart block; sick sinus syndrome; long QT syndrome; severe hypotension; or
decompensated heart failure.