ABR Quality Assurance and Quality Control 3

Question 1

AAPM TG-43 provides the formalism for calculating dose rates in:

Accepted Answer

Brachytherapy source dosimetry

Answer

External beam radiotherapy with photon beams

Answer

Proton therapy planning

Answer

Intraoperative radiation therapy (IORT)

Question 2

The Radiological Physics Center (RPC), now known as the Imaging and Radiation Oncology Core (IROC Houston), primarily serves to:

Accepted Answer

Provide independent dosimetric audits for institutions participating in NCI-funded clinical trials

Answer

Accredit radiation oncology programs for JCAHO

Answer

Manufacture NIST-traceable reference ionization chambers

Answer

Set billing codes for radiation therapy procedures

Question 3

According to TG-142, what is the recommended tolerance for couch vertical, lateral, and longitudinal positioning accuracy?

Accepted Answer

±1 mm

Answer

±0.5 mm

Answer

±2 mm

Answer

±5 mm

Question 4

In brachytherapy QA, the air-kerma strength (SK) of a sealed source is expressed in units of:

Accepted Answer

U (1 U = 1 μGy·m²/h)

Answer

Gray per hour (Gy/h)

Answer

Curie (Ci)

Answer

Becquerel per gram (Bq/g)

Question 5

Which QA parameter is evaluated during a 'picket fence' test on a linear accelerator?

Accepted Answer

MLC leaf positioning accuracy

Answer

Beam energy constancy

Answer

Isocenter size under gantry rotation

Answer

Couch rotation accuracy

Question 6

AAPM TG-40 provides quality assurance guidelines specifically for:

Accepted Answer

Radiation treatment equipment in general (comprehensive periodic QA)

Answer

MRI simulators

Answer

Proton therapy systems

Answer

Stereotactic body radiotherapy (SBRT)

Question 7

During CT simulator QA, the Hounsfield Unit (HU) accuracy is tested primarily because:

Accepted Answer

HU values are used directly to calculate patient dose in external beam planning via electron density conversion

Answer

Incorrect HU values change the CT image color map displayed to physicians

Answer

HU calibration affects the speed of CT image reconstruction

Answer

Errors in HU only affect MRI-compatible planning workflows