Patent · US Expired

Imaging systems

US4307344A · kind A · utility

9Cited by
2References
15Claims
0Family size

Assignee

Inventor

Key dates

Filing dateJan 11, 1980
Grant dateDec 22, 1981
Priority date—
Expiry dateJan 11, 2000

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01R33/4833
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

In a nuclear magnetic resonance imaging apparatus it has been proposed to excite resonance preferentially in a cross-sectional slice of a patient's body by applying a field gradient pulse in conjunction with a pulse of RF. It has been found that the shape of the RF pulse envelope can be chosen to reduce excitation outside the chosen slice. It is proposed that the RF envelope should be a unidirectional pulse of which both the rising and falling parts are monotonic curves lying between limits given by sin.sup.3 t and sin.sup.10 t curves, preferably sin.sup.5 t. An acceptable curve may fall below sin.sup.10 t in the skirts but should not change sign.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.