Sterile elastic masks - a Doctor's best friend? (5)

I believe the answer is:

leela

'a doctor's best friend?' is the definition.
(Doctor Who character)

'sterile elastic masks' is the wordplay.
'masks' indicates the answer is hidden within the clue.
'LEELA' is hidden in the letters of 'sterile elastic'.

I've seen this clue in The Independent.

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