CABT Imaging Systems 3

Question 1

Which nuclear medicine imaging modality provides functional 3D images by detecting pairs of annihilation photons?

Accepted Answer

PET

Answer

PET (Positron Emission Tomography) detects coincident 511 keV annihilation photons produced when a positron meets an electron, enabling 3D functional imaging.

Question 2

In ultrasound imaging, axial resolution is primarily determined by:

Accepted Answer

Transducer frequency and pulse length

Answer

Axial resolution (along the beam direction) depends on the spatial pulse length, which is determined by the transducer frequency and the number of cycles per pulse.

Question 3

A CT system's ability to distinguish between two objects of similar density is described by which performance metric?

Accepted Answer

Low-contrast detectability

Answer

Low-contrast detectability (or contrast resolution) describes the system's ability to differentiate structures with small differences in X-ray attenuation.

Question 4

The ALARA principle as applied to ionizing radiation imaging means:

Accepted Answer

As Low As Reasonably Achievable

Answer

ALARA (As Low As Reasonably Achievable) is the radiation protection philosophy of minimizing patient and staff dose while still obtaining diagnostic quality images.

Question 5

In MRI, the T2* relaxation time differs from T2 because T2* also accounts for:

Accepted Answer

Magnetic field inhomogeneities and susceptibility effects

Answer

T2* (T2-star) is shorter than T2 because it incorporates both true spin-spin relaxation and additional dephasing from local magnetic field inhomogeneities.

(CABT) Certified Associate in Biomedical Technology Practice Test

(CABT) Certified Associate in Biomedical Technology Practice Test

CABT Imaging Systems 3