Automated setting of technic factors for x-ray examinations

• US 4,403,337 A
• Filed: 11/16/1981
• Issued: 09/06/1983
• Est. Priority Date: 11/16/1981
• Status: Expired due to Fees

• Current Assignee: Bennett X-Ray Corp. (Thermo Fisher Scientific Incorporated)
• Original Assignee: Bennett X-Ray Corp. (Thermo Fisher Scientific Incorporated)
• Inventors: Kleinman, Bennett
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US06/321,522
• Time in Patent Office: 659 Days
• Field of Search: 378/95, 378/96
• US Class Current: 378/95
• CPC Class Codes: A61B 5/1077 Measuring of profiles
• CPC Class Codes: A61B 6/469 for selecting a region of interest [ROI]
• CPC Class Codes: A61B 6/544 dependent on patient size
• CPC Class Codes: A61B 6/589 Setting distance between source unit and patient
• CPC Class Codes: H05G 1/46 Combined control of different quantities, e.g. exposure time as well as voltage or current

Abstract

Disclosed is automated setting of x-ray technic factors (KV, MA and exposure time) on the basis of (a) automated determination of the thickness of the patient part to be imaged by a non-contact, sonic ranging system, (b) push button selection for the type of examination, and (c) push button selection for the type of patient physique. The automatically determined technic factors and/or thickness are displayed to allow for manual override, and other failsafe features are provided as well.

Claims

1. A medical x-ray machine comprising:

an x-ray source and an image receptor having an image plane which is at a known distance from the source and is illuminated with x-rays therefrom when the source is energized;

a patient support for locating a patient between the source and image plane such that the distance between the image plane and the patient part to be imaged is fixed but the distance between the part and the source is determined by the unknown thickness of said part;

a sonic transducer which is fixed with respect to the source and sends a sonic signal toward the patient part to be imaged and receives its sonic reflection therefrom;

a travel time derivation circuit coupled with the sonic transducer for deriving therefrom a signal determined by the two-way travel time of the sonic signal between the transducer and the patient part to be imaged;

means for converting the two-way travel time signal to a thickness signal defining the thickness of the patient part to be imaged;

an exposure time circuit responsive to said thickness signal for deriving, at least in part on the basis thereof, a signal defining an exposure time for imaging said patient part; and

means for energizing the x-ray source over an exposure time interval determined at least in part on the basis of said exposure time signal.

2. A medical x-ray machine comprising:

an x-ray source and an image receptor illuminated with x-rays therefrom when the source is energized;

means for locating a patient at a fixed distance from the image receptor;

a sonic transducer which is at a known distance from the receptor and sends a sonic signal toward the patient from the direction of the source and receives the sonic reflection of said signal from the side of the patient facing the source;

means for timing the travel time of said sonic signal to derive therefrom a thickness signal related to the thickness of the patient part to be imaged; and

means utilizing said thickness signal in automatically setting the exposure time for an x-ray examination of said patient part.

3. A medical x-ray examination method comprising:

positioning a patient against an image receptor, with the patient part to be imaged facing an x-ray source, and utilizing a sonic transducer which is at a known distance from the image receptor to send a sonic signal from the direction of the source and to receive the reflection thereof from the patient part facing the source; and

automatically setting the x-ray exposure time at least in part on the basis of the travel time of said sonic signal.