Neuroimaging selection and radiation-aware practice — branching viva

Opening question

This 3-year-old is alert, interactive, has a Glasgow Coma Scale of 15, has not vomited, has no palpable skull fracture, and the parents feel he is acting normally after a one-metre fall. Walk me through how you decide whether he needs a CT head, and tell me what rule you are applying and why it lets you avoid the scan. [1]

Branch 1 — the younger sibling who is drowsy

His 14-month-old sibling fell from the same slide, has a Glasgow Coma Scale of 12, and has a large boggy occipital swelling. What has changed, which PECARN arm now applies, and what is the immediate sequence of management — including the order of resuscitation and imaging? [1] [4]

Branch 2 — defending the radiation risk to an anxious parent

The parent has read online that the CT will give the drowsy sibling cancer. Quantify the attributable lifetime cancer risk of a single paediatric head CT in plain language, name the cohorts that established it, and tell me how you would frame it to a frightened parent so that they consent to a necessary scan without minimising the risk. [2] [3]

Branch 3 — the older sibling with a first unprovoked seizure

Suppose instead that the 7-year-old sibling is brought in after a first afebrile generalised seizure overnight, now back at baseline with a normal examination. What is the imaging strategy, which modality, and why not an urgent CT? Defend it. [5]

Closing — the ALARA principle and the shunted child

Step back. Give me the four levers of ALARA, and tell me how you would apply them across a career to the shunted child who will be scanned many times over a lifetime. [4]