A urologist in Nevada is defending his practice of reusing needles during biopsies – saying he did it based on instructions from a vendor.

In an advertisement in Wednesday’s Las Vegas Review-Journal, lawyers for Dr. Michael Kaplan said that he was told reusing the plastic guides was perfectly safe. The ad says Kaplan stopped reusing them the moment a question arose.

The Southern Nevada Health District said it doesn't know whether any diseases were transmitted, but it is notifying more than 100 patients who had a prostate biopsy from Dec. 20, 2010 to March 11 that they should get tested for HIV and hepatitis.

The Nevada Board of Medical Examiners said Kaplan ordered staff to reuse the guides three to five times. His license was suspended Monday.

The Associated Press contributed to this report.