CT REGISTRY REVIEW: SAFETY
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
CT dose index (CTDI) - ANSWER (T1:26) the approximate radiation dose received by the patient during a
CT scan
bismuth - ANSWER (T1:27, T3:23) contact shields made of ___ may be used to selectively protect
radiosensitive organs (e.g. breast tissue) that lie within the scanned region during a CT acquisition
mAs (mA and time) - ANSWER (T1:28) what technical factor has a direct effect on patient dose?
ionization chamber - ANSWER (T1:29) what device is used to measure the patient dose from a CT
examination?
1. automatic exposure control (AEC)
2. adult and pediatric protocols
3. Digital Imaging and Communications in Medicine (DICOM) radiation dose structured reporting (RDSR)
- ANSWER (T1:30) to meet current industry standards for required dose reduction measures, a CT system
must employ what?
tube milliamperage (mAs) - ANSWER (T1:31) when implementing a scan protocol for a CT of the
abdomen without contrast on a pediatric patient (40lb/18kg), what technical factor should primarily be
adjusted?
effective dose - ANSWER (T1:32) whole-body risk based upon the radiosensativity of exposed tissues
may be estimated using the unit ___
1. decrease in noise on the reconstructed image
2. decrease radiation dose to the patient - ANSWER (T1:33) the use of iterative reconstruction
techniques for CT data processing results in:
, 1. reduce mA
2. limit phases of acquisition
3. increase pitch - ANSWER (T1:34) what methods may be employed to reduce the radiation dose to the
pediatric patient undergoing CT?
increased patient dose - ANSWER (T1:35) a decrease in the focus-to-detector distance of a multidetector
CT (MDCT) system would result in:
CTDIw - ANSWER (T1:36) the radiation dose index calculation that takes into account the variations in
absorption across the field of view due to beam hardening
1. tube current (mA)
2. voltage (kVp)
3. scan time
4. acquisition length
5. pitch
6. collimation width - ANSWER (T1:37) the radiation dose structured report (RDSR) must include what
details regarding CT acquisition?
attenuation - ANSWER (T1:38) the reduction in intensity of the CT x-ray beam as it passes through the
patient tissue
Inappropriate measuring of patient density when employing real-time automatic tube current
modulation - ANSWER (T1:39) How could using in-plane bismuth shielding cause an unnecessary
increase in patient radiation dose?
decrease in mAs (tube current) - ANSWER (T1:39) Increases in kVp (tube potential) should be followed
up by a(n) ___ in order to maintain or decrease patient radiation dose
1. MSAD * slice width (cm) x number of slices in scan volume
2. CTDIvol * scan length (cm) - ANSWER (T1:40) the dose length product (DLP) of a given CT acquisition
may be calculated according to what?
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
CT dose index (CTDI) - ANSWER (T1:26) the approximate radiation dose received by the patient during a
CT scan
bismuth - ANSWER (T1:27, T3:23) contact shields made of ___ may be used to selectively protect
radiosensitive organs (e.g. breast tissue) that lie within the scanned region during a CT acquisition
mAs (mA and time) - ANSWER (T1:28) what technical factor has a direct effect on patient dose?
ionization chamber - ANSWER (T1:29) what device is used to measure the patient dose from a CT
examination?
1. automatic exposure control (AEC)
2. adult and pediatric protocols
3. Digital Imaging and Communications in Medicine (DICOM) radiation dose structured reporting (RDSR)
- ANSWER (T1:30) to meet current industry standards for required dose reduction measures, a CT system
must employ what?
tube milliamperage (mAs) - ANSWER (T1:31) when implementing a scan protocol for a CT of the
abdomen without contrast on a pediatric patient (40lb/18kg), what technical factor should primarily be
adjusted?
effective dose - ANSWER (T1:32) whole-body risk based upon the radiosensativity of exposed tissues
may be estimated using the unit ___
1. decrease in noise on the reconstructed image
2. decrease radiation dose to the patient - ANSWER (T1:33) the use of iterative reconstruction
techniques for CT data processing results in:
, 1. reduce mA
2. limit phases of acquisition
3. increase pitch - ANSWER (T1:34) what methods may be employed to reduce the radiation dose to the
pediatric patient undergoing CT?
increased patient dose - ANSWER (T1:35) a decrease in the focus-to-detector distance of a multidetector
CT (MDCT) system would result in:
CTDIw - ANSWER (T1:36) the radiation dose index calculation that takes into account the variations in
absorption across the field of view due to beam hardening
1. tube current (mA)
2. voltage (kVp)
3. scan time
4. acquisition length
5. pitch
6. collimation width - ANSWER (T1:37) the radiation dose structured report (RDSR) must include what
details regarding CT acquisition?
attenuation - ANSWER (T1:38) the reduction in intensity of the CT x-ray beam as it passes through the
patient tissue
Inappropriate measuring of patient density when employing real-time automatic tube current
modulation - ANSWER (T1:39) How could using in-plane bismuth shielding cause an unnecessary
increase in patient radiation dose?
decrease in mAs (tube current) - ANSWER (T1:39) Increases in kVp (tube potential) should be followed
up by a(n) ___ in order to maintain or decrease patient radiation dose
1. MSAD * slice width (cm) x number of slices in scan volume
2. CTDIvol * scan length (cm) - ANSWER (T1:40) the dose length product (DLP) of a given CT acquisition
may be calculated according to what?
