Most appointments go in the next available slot. A small set of clinical indications need to be seen today — and a second tier needs to be seen within 24–48 hours. This page is the list of what qualifies and how to escalate when no slot is free.
The clinical indication written on the referral is what determines urgency. "My back is really sore" from the patient is not the same as ?cauda equina from the referrer. Book by the wording on the referral. If the patient's story sounds more serious than the referral suggests, that's a reason to call the referrer back — not to upgrade the booking unilaterally.
Don't tell the patient "we're full" and hang up. Put them on hold politely.
Grab the sonographer, radiographer, or on-duty radiologist — whoever covers the modality in question. Read them the clinical indication verbatim.
If they can squeeze the patient in, book it and send the prep/arrival info.
If they can't, call the referrer back (not the patient first). The referrer may want to redirect to ED, another site, or wait — that's their decision, not ours.
Only after speaking with the referrer, call the patient back with the plan.
If the indication is genuinely acute and we have no capacity, advise the patient to present to their nearest emergency department — but do this with the referrer's knowledge wherever possible.