Patent Document ID: 6097994
Application ID: 08722708
Patent Status: 1

Claim One:
1. Apparatus utilizing information from a plurality of fluoroscopic images formed from different radiation source positions for determining a proper insertion depth of a biopsy needle to be inserted at a selected point on the body of a patient so that a sampling end of said needle just reaches to a designated target area within said body, said apparatus comprising: at least one straight calibrated pointing device aligned to point through said selected point in a straight line passing through said designated target region, said pointing device exhibiting first and second markers along its length such that respective images are formed on each of first and second image planes by utilizing radiation from respective first and second radiation source positions, along with images corresponding to said selected point and said target area, said images being formed along a straight line in this order: (A) said first marker, (B) said second marker, (C) said selected point, and (D) said target region; means for measuring distances on at least one of said first and second image planes between images (A), (B), (C), and (D); and means for calculating the cross ratio of said distances, whereby said proper insertion depth of said biopsy needle is determined.