Radiation protection and imaging stewardship — branching viva

Opening question

This child has had several surveillance CT scans and is due for another. Give me the three pillars of radiological protection, and tell me which of them applies to a patient investigation and which does not — and why. [8]

Branch 1 — quantifying and defending the radiation risk

His parent has read online that the repeated scans will give him cancer. Quantify the effective dose and the attributable lifetime cancer risk of a single paediatric CT in plain language, name the cohorts that established the estimate, and tell me how you would frame it to the parent so that they consent to a necessary surveillance scan without minimising or exaggerating the risk. [1] [2] [3]

Branch 2 — the multiphase CT and the optimisation levers

A colleague proposes a multiphase abdominal CT for a child with suspected nephrolithiasis. Defend or challenge that request on stewardship grounds, name the dose quantities affected, and give me the optimisation alternative — including the role of a non-ionising modality. [8] [10]

Branch 3 — the diagnostic reference level

The department is reviewing its diagnostic reference levels. Define the diagnostic reference level, tell me how it is set and what it is not, and explain why it must be size-stratified in children. [10]

Closing — gonadal shielding and the modern position

Step back. The radiographer asks whether to apply a gonadal shield to a child's pelvic radiograph. Give me the current recommendation and the reasoning, and tell me where shielding still has a role. [12]