A search of the vascular specialist 's offices and home produced "huge amounts" of photographs showing the violation of at least four female participants of purported varicose vein research tests he conducted at the hospital in Bamberg according to police.
The doctor was taken into custody on Wednesday morning.
Authorities were first alerted in July by a medical student participating in the tests after she reported that the doctor had administered an injection without her permission. She lost consciousness for an hour and had no recollection of events.
A subsequent blood test showed that a high dosage of an anaesthetic had been administered and the designated tests were not carried out, Bavarian prosecutors said.
That alone constituted a charge of assault. But examination of the seized photos of the woman and other apparent test participants have resulted in at least three charges of rape and one of sexual abuse.
"A first evaluation of the impounded materials shows that the hospital doctor clearly exploited the sedated state of his test subject and perpetrated abuse of a sexual nature on his helpless victim, and then documented this photographically," a police statement said regarding the medical student who lodged the complaint.
The alleged incidents took place outside normal working hours, colleagues said, otherwise the doctor would not have been alone with test participants.
The accused has worked at Bamburg's Clinic for Vascular Surgery for nine years and reportedly held a senior position since 2007. He had been nationally and internationally recognized for his work.