Exhibit 17.1

Patrick L. Flinn

1050 N. Waterway Drive

Fort Myers, Florida 33919

May 18, 2006

Orwin L. Carter, Ph.D.

Chairman of the Board

Theragenics Corporation

1029 3d Avenue South

Stillwater, MN 55082

Dear Orwin,

For personal reasons I tender my resignation from the Board of Directors of Theragenics Corporation. This action to be effective immediately.

Sincerely,

/s/ Patrick L. Flinn