MRI QA

Question 1

What are the ideal requirements for Radiotherapy planning?

Answer 1

Flat top couch - no carbon fibre or metal
Lasers - MR compatible
Large bore
Coil supports - preserves skin contour
Location mechanism needs to be compatible with immobilisation devices

Question 2

What considerations need to be made for Radiotherapy QC?

Answer 2

Geometric distortion - non linear in static and gradient fields
Effect of RT couch on image quality
Consistency of image quality parameters

Question 3

What are the available QC tests?

Answer 3

Magnetic field homogeneity evaluation
Slice position and thickness accuracy
RF coil checks - SNR, image intensity uniformity
Table accuracy
Laser set-up
Laser movement accuracy
High contrast spatial resolution
Artefact evaluation
Centre frequency
Transmitter gain or attenuation
Low contrast detectability

Question 4

Why is using the ACR phantom advantageous?

Answer 4

Tolerances are documented and there is an accreditation program