I would check with Bridge Clinic. They have a pretty solid in-house diagnostic set-up that may include the ability to do this, and they’re set up as a non-profit. Between their mission and ability to do most stuff in-house, they’re routinely substantially cheaper than most other offices for big ticket items.

You’ll have to drive up to Bucks County, but for something like this, it’s worth the trip.

I don’t think PAWS or PSPCA has the equipment to do this for you, but they’d also be a good option if they do. Can’t hurt to get in touch and ask.