Knocking sound & vibration at passenger wheel during braking on 2002 Toyota Corolla

When braking, I get a vibration and noticeable knocking sound from the front passenger wheel area. Would like to have some idea whether this is an issue with the brakes vs. suspension prior to visiting mechanic. Both the vibration and sound have been getting progressively worse over time. Neither are present during acceleration or cruising.

Asked by for the 2002 Toyota Corolla
It is important to get this looked at as it may be potentially very dangerous. It could be many things. I would imagine it is brake and not suspension related. Perhaps the brake caliper mount, brake caliper shims, or caliper to mounting bracket bolts that have come loose. If it were suspension related you would hear a rattle with suspension change (like driving over a speed bump).