Guide block for biopsy or surgical devices

A system comprising:

• a grid-like, breast-receiving pressure plate having a polygonal opening;
• and
• a prism having a proximal shoulder, matching the polygonal opening, and including:
• a first conduit that has a zero first offset from the prism center;
• a second conduit that has a second offset from the prism center, that lies between the prism center and a first prism corner, and that intersects the first conduit;
• a third conduit that has a third offset from the prism center and that lies between the prism center and a prism face;
• and
• a fourth conduit that has a fourth offset from the prism center and that lies between the prism center and a second prism face,
• wherein:
• the first and second conduits longitudinally intersect;
• the first and third conduits share a longitudinally oriented connecting region;
• the second offset is larger than the first offset, the third offset is larger than the second offset, and the fourth offset is larger than the third offset;
• and
• each of the first conduit, the second conduit, the third conduit and the fourth conduit is configured to receive a tissue removing device.