U.S. patent number 3,648,685 [Application Number 04/836,315] was granted by the patent office on 1972-03-14 for photoelectric probes for determining the density of body tissue for x-ray purposes.
Invention is credited to James A. Hepp, Gary E. Roberts.
United States Patent |
3,648,685 |
Hepp , et al. |
March 14, 1972 |
PHOTOELECTRIC PROBES FOR DETERMINING THE DENSITY OF BODY TISSUE FOR
X-RAY PURPOSES
Abstract
An internal probe to be inserted in the mouth and an external
probe to be positioned externally of the mouth in alignment with
the internal probe, said probes projecting in substantially
parallel relation from a handle member, the internal probe
terminating in a photoelectric cell and the external probe
terminating in a light source optically aligned with said photocell
so as to project light through the mouth tissue to said photocell
to activate a meter, the reading of which is proportionate to the
opaqueness or density of the intervening tissue so as to provide
means for determining in advance the apparatus exposure time
necessary to obtain an acceptable X-ray picture of the intervening
tissue.
Inventors: |
Hepp; James A. (Erie, CO),
Roberts; Gary E. (Loveland, CO) |
Family
ID: |
25271703 |
Appl.
No.: |
04/836,315 |
Filed: |
June 25, 1969 |
Current U.S.
Class: |
600/476;
356/41 |
Current CPC
Class: |
A61B
5/0088 (20130101); A61B 6/145 (20130101); G01J
1/4214 (20130101); A61B 2562/0238 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); A61B 6/14 (20060101); G01J
1/42 (20060101); A61b 006/08 (); G01n 033/16 () |
Field of
Search: |
;128/2,25P,25F,25A,25R,25T,25V,25B,25S ;356/39-42 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Howell; Kyle L.
Claims
Having thus described the invention what is claimed and desired to
be secured by Letters Patent is:
1. A photoelectric probe for determining the density of body tissue
for X-ray purposes comprising:
a. a handle element;
b. a first stem mounted in and projecting from said handle
element;
c. a second stem mounted in and projecting from said handle element
adjacent to said first stem;
d. a photoelectric cell supported by said second stem;
e. a light source supported by said first stem so as to project a
beam of light against said photoelectric cell;
f. means for supplying electrical power to said light source;
g. meter means connected with said photoelectric cell and acting to
indicate the electric alterations caused by the incidence of said
beam upon said cell;
h. means in said handle element for adjustably varying the distance
between said light source and said photoelectric cell;
i. means in said handle element for varying the intensity of said
beam;
j. the means for varying the intensity of said beam is connected to
and actuated by the means for varying the distance between said
light source and said photoelectric cell whereby the intensity of
said light source decreases as the distance between said light
source and said cell decreases; and
k. a socket element shiftably mounted in said handle element, said
first stem being mounted on said socket element for movement
therewith.
2. A photoelectric probe as described in claim 11 having:
a. a cavity formed in said handle member;
b. said socket element positioned in, and shiftable from side to
side of said cavity,
c. means for shifting said socket member from side to side of said
cavity; and
d. means for maintaining said socket member aligned in said cavity
at all shiftably-attained positions.
3. A photoelectric probe as described in claim 2 in which the means
for maintaining said socket member aligned comprises;
a. a pair of parallel guide rods extending across said cavity
through said socket member in the plane of said stems, said socket
member being slidably fitted on said rods so as to be maintained
vertical thereby.
4. A photoelectric probe as described in claim 3 in which the means
for shifting said socket member comprises:
a. shaft-supporting means fixedly mounted in said handle element at
one side of said cavity between said guide rods;
b. a rotatable threaded shaft extending from said shaft-supporting
means across said cavity parallel to said rods, said socket member
being threaded upon said shaft so that reciprocal rotation of the
latter will impart reciprocal movement of said socket member along
said rods.
5. A photoelectric probe as described in claim 3 in which the means
for shifting said socket member comprises:
a. a rotary-type potentiometer fixedly mounted in said handle
element at one side of said cavity between said guide rods;
b. a threaded potentiometer-actuating shaft extending from said
potentiometer across said cavity parallel to said rods, said socket
member being threaded upon said shaft so that reciprocal rotation
thereof of the latter will impart movement of said socket member
along said rods.
6. A photoelectric probe as described in claim 5 in which:
a. the potentiometer is connected in series with the power supply
to the light source so that rotation of said shaft simultaneously
shifts the socket element and varies the intensity of the light
source.
Description
This invention relates to means for determining in advance the
proper X-ray camera exposures to be used to produce the most
effective photographic results in a given situation. Since X-ray
films are produced by the passage of rays through intervening
tissue and since the density of the tissue of course affects the
passage of the rays it is difficult to assume in advance the
correct exposure that will be required in the many different
situations encountered in actual practice. It is usually a case of
"trial and error." This often requires additional time and film to
correct the overexposed and underexposed trials.
The principal object of this invention is to produce a relatively
simple, easily used exposure meter for X-ray photographs which will
enable the user to readily and accurately determine in advance the
exposure time that will be required to obtain the best result in
each specific case so as to avoid the loss of time and materials
occasioned by the present trial and error methods.
While the invention is similarly useful in many X-ray problems it
is particularly adaptable, but not limited, to use by the dental
profession where rapid X-rays are required to further the work
being performed while the patient remains in place in the dental
chair.
Other objects and advantages reside in the detail construction of
the invention, which is designed for simplicity, economy, and
efficiency. These will become more apparent from the following
description.
In the following detailed description of the invention, reference
is made to the accompanying drawing which forms a part hereof. Like
numerals refer to like parts in all views of the drawing and
throughout the description.
In the drawing:
FIG. 1 is a side view of the probe of this invention illustrating
in broken line the relative position of a patient upon which the
probe is being used;
FIG. 2 is a front view of the probe;
FIG. 3 is a cross-sectional view looking downwardly on the line
3--3, FIG. 1;
FIG. 4 is a fragmentary longitudinal section taken on the line
4--4, FIG. 2;
FIG. 5 is a top view of the probe; and
FIG. 6 is a circuit diagram suggesting how the probe may be
combined with amplifying and metering circuits.
Briefly, the probe comprises a handle block 10, preferably formed
of molded plastic, from the upper extremity of which a light stem
11 and a tubular metallic photoelectric cell stem 12 project in
substantially parallel relation. The light stem 11 terminates in a
relatively wide hollow lamp head 13 having a removable lens bezel
14 which supports an elongated projection lens 15 thereon. The
photocell stem 12 terminates in a substantially cylindrical
cup-shaped cell head 16 having a removable lens bezel 17 which
supports an elongated light receiving lens 18 thereon. The stems 11
and 12 are so contoured that the lenses 15 and 18 face each other
in axial alignment.
A suitable, conventional photoelectric type incandescent lamp 19 is
mounted in the lamp head 13 so as to project a light beam "A"
through the lenses 15 and 18 into a hermatically sealed photocell
20, of the light-controlled variable resistor type, which is
mounted in the cell head 16.
The lower extremity of the tubular photocell stem 12 is fixedly
mounted in a suitable receiving socket 21 in the top of the handle
block 10. The lower extremity of the tubular light stem 11 is
fixedly mounted in a socket 22 in the top of a vertically elongated
shiftable socket element 23 positioned in a vertical cavity 21 in
the handle block. The shiftable socket element 23 is preferably
substantially square in cross section and is positioned between the
side walls of the cavity 23 which is transversely widened to allow
the lateral shifting of the socket element in the handle block for
varying the distance between the lamp head 13 and the cell head 16.
The socket element 23 is slidably mounted on, and maintained
vertical in the cavity 24 by, two horizontal, vertically spaced
guide rods 25 which pass through the handle block and are rigidly
mounted therein by means of terminal clamp screws 26.
The socket element 23 can be shifted along the guide rods 25 in any
desired manner. As illustrated, the shifting is accomplished by
fixedly mounting a rotary type potentiometer 27, having a threaded
shaft 28, in one side of handle block between the guide rods 25 and
extending its shaft 28 across the cavity 24 and through a threaded
hole in the socket element so as to terminate in a knurled
adjusting knob 29 at the other side of the handle block. It can be
seen that reciprocal rotation of the knob 29 will cause the socket
element to reciprocally travel along the guide rods.
For the purpose of clarity the conventional wiring and connections
have been omitted from the sectional views of the drawing and are
shown diagrammatically in FIG. 6 of the drawing in which a
conventional photoelectric power supply is indicated at 30 fed from
the 110 v. house circuit as indicated at 31. The power supply
furnishes the correct voltage through lamp leads 32 to properly
illuminate the lamp 19, and also receives the output of the
photocell 20 through photocell leads 33 and amplifies the same to
actuate a suitable milliammeter 34. The lamp leads 32 and the
photocell leads 33 are inclosed in a suitable flexible multiple
cord 35 leading from the handle block to the power supply 30.
It will be noted that the potentiometer 27 is connected in series
with the lamp leads 32 so that the rotation of the potentiometer
shaft 28 serves a double purpose. It provides means for clamping
the lenses 15 and 18 snugly against the opposite sides of the
intervening tissue and it provides means for automatically and
proportionately varying the lamp intensity in correspondence with
the varying separations between the light source and the photocell.
The potentiometer 27 and the threads on its shaft 28 are accurately
pre-positioned so as to maintain the intensity of the light
impinging upon the photocell uniform at all possible separations
between the lamp and the cell so that the variation of the readings
of the meter 34 will be unaffected by the separations, so as to be
an index of tissue density only.
For dental use, the stems 11 and 12 are separated and the cell head
16 is positioned within the mouth at the point of operation and the
lamp head 13 is positioned against the face above the lip, as shown
in FIG. 1. The knob 29 is then rotated to bring the lenses 15 and
18 and their bezels 14 and 17 against the tissue so as to shield
against external light. The meter 34 is then read to obtain the
desired index for proper X-ray exposure.
While a specific form of the invention has been described and
illustrated herein, it is to be understood that the same may be
varied within the scope of the appended claims, without departing
from the spirit of the invention.
* * * * *