Mechanical index can be used as an estimate for the degree of bio-effects a given set of ultrasound parameters will induce. A higher mechanical index means a larger bio-effect. Currently the FDA stipulates that diagnostic ultrasound scanners cannot exceed a mechanical index of 1.9.
- Thomas Szabo (2004). Diagnostic Ultrasound Imaging: Inside Out (Biomedical Engineering). ISBN 978-0-12-680145-3
- http://www.accessdata.fda.gov/cdrh_docs/pdf9/K091970.pdf (accessed July 2010)