Routine post-acquisition verification of HU values is uncommon and knowledge of positioning effects on CT numbers is inconsistent¶

Claim · All claims
Evidence · 1 study (2 entries) · associational r1 · q2
Currency · newest study 2026 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Most radiographers check HU values only sometimes (37.4%), rarely (35.2%) or never (13.4%), with regular verification reported by a small minority. → Hadi Yasser H. 2026 q2 i? Understanding of whether HU values change with mis-centring was split: 39.3% answered probably yes, 23.7% might or might not, and 18.4% probably not. → Hadi Yasser H. 2026 (2)

Evidence¶

Hadi Yasser H. 2026¶

Hadi Yasser H., Bani‐Ahmad Mo'men, Moore Niamh, Clark Kevin R., Al‐Hayek Yazan, Albeshan Salman M., Alghamdi Sultan B., Precht Helle, England Andrew, McEntee Mark. (2026). Patient Centring in CT: An International Survey of Clinical Practice and Future Directions. Journal of Medical Radiation Sciences. https://doi.org/10.1002/jmrs.70119

q2 · i? · associational · r1

Survey item on routine post-acquisition HU verification among 321 radiographers; only 10.9% reported checking often and 3.1% always, which the discussion frames as a knowledge–practice gap needing targeted education.

"the most frequently selected option was ‘sometimes’ checking HU values (120, 37.4%), followed by ‘rarely’ (113, 35.2%) and ‘never’ (43, 13.4%)."

Hadi Yasser H. 2026 (2)¶

Hadi Yasser H., Bani‐Ahmad Mo'men, Moore Niamh, Clark Kevin R., Al‐Hayek Yazan, Albeshan Salman M., Alghamdi Sultan B., Precht Helle, England Andrew, McEntee Mark. (2026). Patient Centring in CT: An International Survey of Clinical Practice and Future Directions. Journal of Medical Radiation Sciences. https://doi.org/10.1002/jmrs.70119

q2 · i? · associational · r1

Survey item asking whether HU values change when patients are not aligned with the gantry isocentre; responses were distributed across certainty levels, with only 12.5% selecting definitely yes and 6.2% definitely not.

"‘probably yes’ was the most common response (126, 39.3%), followed by ‘might or might not’ (76, 23.7%) and ‘probably not’ (59, 18.4%)."

Discussion¶

Related Claims¶

• Access to and consistent use of automated centring technology remain limited among CT radiographers — related
• Mean CT centring knowledge score indicates only moderate proficiency, with greater score variability among less experienced and lower-volume radiographers — related
• Radiographers show substantial uncertainty about how localiser radiograph direction affects radiation dose and ATCM behaviour — related
• Vertical off-centring below the gantry isocentre is the most frequently reported CT positioning error among radiographers — related
• CT-specific qualification, experience and workload were not significantly associated with high CT centring knowledge scores in the international sample — related