A percutaneous tool or device intended for image-guided placement or operation under medical imaging is fabricated with materials such as aluminum or aluminum alloys rather than stainless steel, or is otherwise configured to prevent beam hardening and the loss of low energy beam data during medical imaging that could otherwise degrade or produce confounding artifacts in the image. The improved tool, such as a percutaneous microwave ablation antenna or biopsy needle, can be more reliably and accurately positioned in relation to a targeted tissue site and thus operated more precisely and completely treat or sample a tumor or other tissue target in the body of a patient.
