It would be very unlikely, sorry

I know a Japanese radiologist, and dentist, two doctors and a guy who does something to do with implants during surgery.. and have heard a bit about the health care world here...
Combining that with the visa rules and Japanese people's attitudes about foreigners..
even if your written and spoken Japanese was perfect.. I could not imagine it ever happening.
Too many Japanese people wanting jobs like that.. and employers prefer to have Japanese staff working them because they understand what is expected of them.
If you wanted to find out if I am right or wrong, you could surf the Japan job sites (some on this page) and see what you can find.