Thermographic apparatus

• US 4,379,461 A
• Filed: 09/17/1980
• Issued: 04/12/1983
• Est. Priority Date: 01/17/1979
• Status: Expired due to Term

• Current Assignee: Erling S. Nilsson, Staffan G. Zetterquist
• Original Assignee: Erling S. Nilsson, Staffan G. Zetterquist
• Inventors: Nilsson, Erling S., Zetterquist, Staffan G.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US06/204,366
• Time in Patent Office: 937 Days
• Field of Search: 128/736, 73/343.5, 73/344, 73/340, 73/341, 346/33 ME, 346/33 TP
• US Class Current: 600/549
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: G01D 9/38 Producing one or more recordings, each recording being produced by controlling the recording element, e.g. stylus, in accordance with one variable and controlling the recording medium, e.g. paper roll, in accordance with another variable
• CPC Class Codes: G01K 1/022 for recording

Abstract

The invention relates to a thermographic apparatus intended in particular for diagnosing disturbances in circulation in the extremities of a patient, by recording the temperature distribution along a selected line extending from the ankle of a patient up to the thigh on both legs of the patient, whereafter any asymmetry in the two registered temperature profiles is used for the basis of a diagnosis. The apparatus comprises a temperature transducer (4), preferably an IR-detector, which is carried on one end of an extendable and retractable arm (6), so that the transducer can be moved manually along a selected line on the leg (2) of the patient. Coupled to the arm (6) is a position transducer (11) for generating an electric signal representative of the distance moved by the temperature transducer. The apparatus also includes a recorder (10) to which both the temperature signal and the position signal are transmitted and which is arranged to record the measured temperature profile simultaneously. This sequence can be repeated on the other leg of the patient, so that the recorder records both temperature profiles. The apparatus also includes a signal-processing unit (14a, 14b) in which the analogue temperature signals and position signals are converted to digital form and stored so that they can later be processed in a calculator part (14c) which calculates the difference between the temperatures in mutually corresponding locations on the two legs of the patient, whereby a temperature difference-position-relationship is obtained, which after being converted to analogue form can be transmitted to the recorder (10) and recorded thereby.

Claims

1. An apparatus for detecting circulation disturbances in the legs of a patient by measuring and recording the skin surface temperature along the legs of the patient, comprising:

at least one temperature sensor manually movable over the skin surface along the legs of a patient resting with his legs in a substantially horizontal position and capable of sensing the skin surface temperature of the momentarily adjacent portion of the patient'"'"'s leg and generating an electric signal corresponding thereto;

a movable apparatus frame structure adapted to be located at the feet of a patient under examination;

means mechanically connecting said temperature sensor to said apparatus frame and including signal generating means responsive to the movement of said temperature sensor relative to said apparatus frame and for generating an electric signal representing the position of the temperature sensor along its path of movement;

signal recording means mounted in said apparatus frame for receiving said temperature signal and said position signal and capable of recording the temperature being sensed as a function of the position of the temperature sensor; and

digital signal processing means mounted in said apparatus frame for receiving said temperature and position signals and including data storing means for storing associated values of said temperature and position signals from at least two, different, measured temperature-position-relations and calculating means for comparing the temperature values as a function of the position for said two temperature-position-relations stored in said storing means and for producing signals representing the temperature difference as a function of the position for said two temperature-position relations, said recording means being capable of receiving said last mentioned signals for recording said temperature difference as a function of the position.

2. An apparatus as claimed in claim 1, wherein said mechanical connecting means comprise an extendable and retractable arm having one end mounted on said apparatus frame and an opposite end carrying said temperature sensor in a manner such that the temperature sensor can be moved linearly along the legs of the patient by extending or retracting said arm, and wherein said signal generating means responsive to the movements of the temperature sensor comprise a position transducer coupled to said arm for generating an electric signal representing the linear distance between said one end and said opposite end of said arm.

3. An apparatus as claimed in claim 2, further including:

a carriage on which said one end of said extendable and retractable arm is supported, said carriage being mounted for movement on said apparatus frame in a direction substantially perpendicular to the direction in which the arm is extendable and provided with means for locking the carriage in a selectable position; and

a second position transducer, coupled to said carriage, for generating a second electric position signal representative of the position of said carriage in its direction of displacement, wherein said recording means are capable of receiving also said second position signal and of recording the temperature being sensed as a function of both the extension of said arm and the position of said carriage.

4. An apparatus as claimed in claim 2, further including a substantially vertical post mounted on said apparatus frame, said arm being vertically adjustably mounted on said post.

5. An apparatus as claimed in claim 2, wherein said one end of said arm is displaceable on said apparatus frame in the direction in which the arm is extendable.

6. An apparatus as claimed in claim 1, further including a timer for generating an electric time signal, said signal recording means being capable of receiving said time signal and of recording the temperature being sensed as a function of time.

7. A method for detecting circulation disturbances in the legs of a patient by measuring and recording the skin surface temperature along the legs of the patient, using the apparatus in accordance with claim 1, comprising:

placing said apparatus frame at the feet of a patient whose legs are horizontally disposed;

moving said temperature sensor over the skin surface along one leg of the patient;

recording the temperature being sensed as a function of the position of said sensor by means of said signal recording means;

repeating said moving and recording steps with respect to the other leg of the patient; and

recording the temperature differences between the two legs of the patient as a function of position by means of said digital signal processing means and said recording means.