(AREA) -- Medicare's massive claims database lists a Detroit-area cancer doctor accused of intentionally misdiagnosing patients and ordering unnecessary treatments. Farid Fata, among the top billers, is awaiting trial on federal charges. He says he's innocent. Fata was arrested last August. He's accused of committing fraud to enrich himself through health insurance programs. The government says his practice billed Medicare $225 million from August 2007 to July 2013. He could face trial this year. An analysis by The Associated Press found that a tiny group, 344 out of more than 825,000 doctors, received $3 million or more apiece in 2012- a threshold that raises eyebrows for the government's own investigators. Overall, about 2 percent of clinicians accounted for one-fourth of payments. The government says Fata ripped off Medicare by giving chemotherapy to patients who didn't need it and diagnosing cancer when it wasn't apparent. Fata owned Michigan Hematology Oncology, which has an office in Lapeer.