Method of measuring temperature change and SAR of artificial hip joint implant using magnetic resonance imaging equipment
AssigneeKorea Research Institute of Standards and Science
InventorYoungseob Seo
Life of this patent
Estimating the term…
Abstract
A method of measuring a specific absorption rate (SAR) of a hip joint implant using magnetic resonance imaging (MRI), includes: arranging the hip joint implant in a human lower body-shaped phantom; arranging an electric field sensor around the hip joint implant; providing radio frequency (RF) energy according to an MRI sequence to the human phantom; and calculating the SAR of the hip joint implant from strength of an electric field measured by the electric field sensor.
Claims6
A method of measuring a specific absorption rate (SAR) of a hip joint implant using magnetic resonance imaging (MRI), the method comprising:
- arranging the hip joint implant in a human lower body-shaped phantom;
- arranging an optical electric field sensor around the hip joint implant;
- providing radio frequency (RF) energy according to an MRI sequence to the human phantom;
- and
- calculating the SAR of the hip joint implant from strength of an electric field measured by the optical electric field sensor;
- wherein the calculating of the SAR of the hip joint implant includes calculating Equation
- SAR
-
- (
- r
- →
- ,
- t
- ,
- f
- )
- =
- σ
-
- (
- f
- )
- ×
- ❘
- "\[LeftBracketingBar]"
- E
- →
- (
- r
- →
- ,
- t
- ,
- f
- )
- ❘
- "\[RightBracketingBar]"
- 2
- 2
-
- ρ
- ,
- where, σ denotes electrical conductivity of tissue, ρ denotes the bulk density, {right arrow over (E)} denotes a three-component electric field strength vector (x, y, z), {right arrow over (r)} denotes a three-component spatial position vector (x, y, z), f denotes an RF, and t denotes an elapsed time.
A method of measuring temperature rise of a hip joint implant using magnetic resonance imaging (MRI), the method comprising:
- arranging the hip joint implant in a human lower body-shaped phantom;
- arranging a plurality of temperature sensors on the hip joint implant;
- providing radio frequency (RF) energy according to an MRI sequence to the human phantom;
- measuring, by the temperature sensors, a change in temperature of the hip joint implant;
- calculating, by the temperature sensors, a specific absorption rate (SAR) of the hip joint implant from the measured temperatures;
- wherein the plurality of temperature sensors are configured to:
- measure ambient temperatures of the hip joint implant;
- and
- calculate the SAR of the hip joint implant from the measured temperatures;
- wherein the SAR is obtained by calculating Equation
- SAR
- =
- c
- p
-
- ΔTemperature
- Δtime
- here, cp=4,156 J/(kg·° C.), cp denotes heat capacity of a gel material, ΔTemperature denotes a change in temperature in degree Celsius (° C.), the change in temperature ° C. is a difference between a temperature measured when an artificial hip joint is inserted and a temperature measured before the artificial hip joint is inserted, and Δtime denotes a time in seconds, the time in seconds is an image capturing time for each sequence.
Dependencies are inferred from the claim text.