72 dpi or ppi is meaningless with respect to television. 72 dpi would mean that your TV is always 10 inches wide by 6.6 inches.
What matters (in non-print applications) is the final size of your scan in pixels. You should ask for the resolution (dpi or ppi) that will give you that pixel size. If your film is 2.25 inches each side, and you want, say, an image that is 2250×2250 pixels, you scan at 1000 dpi.
2.25 x 1000 = 2250.
If you scanned at 150 dpi, your image would only be 338 pixels on each side. I don’t think that’s what you want.
So begin with the end in mind (pixels), then choose a dpi value that will give you that size in pixels.
Steve