Gauss–Bonnet gravity: Difference between revisions
Jump to navigation
Jump to search
en>Paine Ellsworth m condense citation + endashes |
en>Enyokoyama |
||
| Line 1: | Line 1: | ||
'''Mechanical index''' ('''MI''') is an [[ultrasound]] metric. It is defined as <ref>Thomas Szabo (2004). ''Diagnostic Ultrasound Imaging: Inside Out (Biomedical Engineering)''. ISBN 978-0-12-680145-3</ref> | |||
:<math> \text{MI} = \frac{\text{PNP}}{\sqrt{F_c}},</math> | |||
where | |||
:*PNP is the peak negative [[pressure]] of the ultrasound wave ([[Pascal (unit)|MPa]]), derated by 0.3 dB cm<sup>-1</sup> MHz<sup>-1</sup> to account for the difference between in-water and in-tissue acoustic attenuation, and | |||
:*''F<sub>c</sub>'' is the [[center frequency]] of the ultrasound wave ([[Hertz|MHz]]). | |||
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 [[Food and Drug Administration|FDA]] stipulates that diagnostic ultrasound scanners cannot exceed a mechanical index of 1.9.<ref> http://www.accessdata.fda.gov/cdrh_docs/pdf9/K091970.pdf (accessed July 2010)</ref> | |||
==References== | |||
{{Reflist}} | |||
[[Category:Acoustics]] | |||
[[Category:Ultrasound]] | |||
[[Category:Medical physics]] | |||
[[Category:Medical ultrasonography]] | |||
Revision as of 12:28, 10 December 2013
Mechanical index (MI) is an ultrasound metric. It is defined as [1]
where
- PNP is the peak negative pressure of the ultrasound wave (MPa), derated by 0.3 dB cm-1 MHz-1 to account for the difference between in-water and in-tissue acoustic attenuation, and
- Fc is the center frequency of the ultrasound wave (MHz).
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.[2]
References
43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.
- ↑ 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)