QA

Question 1

TG-66 QA of CT Image: Daily Test

Answer 1

Alignment of gantry lasers with the center of imaging plane +/- 2mm
CT number accuracy for water +/- 5 HU
Image noise
In plane spatial integrity +/- 1mm

Question 2

TG-66 QA of CT Image: Monthly Test

Answer 2

Orientation of gantry lasers with respect to imaging plane +/- 2mm
Spacing of lateral wall lasers +/- 2mm
Orientation of wall lasers +/- 2mm
Orientation of ceiling laser +/- 2mm
CT number accuracy 4-5 different materials
In plane spatial integrity in x and y direction
Field uniformity most commonly used kVp

Question 3

TG-66 QA of CT Image: Annual Test

Answer 3

CT number accuracy electron density phantom
field uniformity all kVp settings +/- 5 HU
electron density to CT number conversion
Spatial resolution
Contrast resolution
*CT dose index, patient dose from CT scan +/- 20% manufacturer specifications

Question 4

Dose from CBCT

Answer 4

1 cGy

Question 5

AAPM TG142 Imaging QA for the Linac: Daily

Answer 5

Planar kV and MV (EPID) imaging:

Question 6

AAPM TG142 Imaging QA for the Linac: Monthly

Answer 6

Planar MV imaging (4 cardinal angle coincidence (2mm nonSBRT, 1mm SBRT), scaling, spatial resolution, contrast, uniformity and noise)
Planar kV imaging (coincidence and scaling:

Question 7

AAPM TG142 Imaging QA for the Linac: Annual

Answer 7

Planar MV imaging full range of travel SDD +/- 5mm; imaging dose
Planar kV imaging beam quality/energy