LOR from Doctor I shadowed?

I live in FL but am from Toronto. To make these visits productive, every time I went back home to visit, I shadowed a family physician. I did almost 100 hours of shadowing for him and we have a great relationship. He is willing to write me a LOR. Can I use a Canadian MD LOR for my AMCAS application? Would this be beneficial? I also am focused in going into primary care. My other choice is a DO in the US I did research for one semester. But I am not as close with him.
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums