A national association of medical and dental practitioners has begun questioning its members about defects in endoscopes and manufacturers' responses to complaints, according to a group bulletin made available Wednesday.

A questionnaire by the 94,000-member association — the Japanese Medical and Dental Practitioners for the Improvement of Medical Care — comes on the heels of a lawsuit filed by a doctor seeking damages from Toshiba Corp. over claims the company ignored complaints regarding its endoscope.

Endoscopes are used to visually examine the insides of hollow organs.