Mammography: how much is reimbursed?

A female auditor from the canton of Vaud had to pay over 400 francs out of her own pocket for a mammogram prescribed by her gynecologist and carried out at lʹhôpital de Nyon. Apparently, according to her insurer, only screenings carried out as part of a cantonal program are reimbursed. Is he right? Do you have to go to a recognized center for your mammogram to be covered by your health insurance? And under what conditions?