Apparatus for thermographic examinations

A method and apparatus for conducting thermographic examinations of localized portions of the body in which a localized area of the body is cooled. A liquid crystal film is affixed directly against the body and the localized area and film are re-cooled to a uniform temperature. The localized area of the body and the film are rewarmed and visual images appearing on the liquid crystal film, as surface temperatures increase through the sensitivity range of the film, are recorded.

BACKGROUND OF THE INVENTION 
The present invention relates to the art of thermographic imagery and, in 
particular, an apparatus and method for improving thermographic imagery 
through the use of controlled temperatures. 
The medical community became interested in thermography as a diagnostic 
tool as early as 1956, when it was discovered that skin overlying breast 
cancer had elevated temperatures as compared to normal tissue. Several 
thermographic systems have become available in the United States including 
the AGA THERMOVISION, BOFORS M-101, SPECTROTHERM AND THERMISCOPE. Contact 
thermograpy utilizing liquid crystals calibrated to change color at 
predetermined temperatures became available in 1969. Liquid crystal films 
embedded in elastomeric film became available in 1980. 
Despite the great advances in imaging processes, designs and electronic 
hardware, thermography remains plagued with numerous false negatives and 
false positive results which detract from its usefulness as a diagnostic 
tool. The problem with present thermographic techniques is related to its 
dependence on passive measurements of surface temperature of the subject 
skin. Various surface temperature variations and the presence of 
nonspecific isotherms occur frequently. The surface temperature of the 
skin is a nonspecific physiological modality, heavily influenced vascular 
changes, changes in biological activity, tissue conductivity, and 
environmental factors. 
In conventional thermography, objects with the same surface temperature 
will appear the same because they have the same isotherms. Objects with 
the same surface temperature as their surroundings cannot be distinguised 
or separated. In conventional thermography, a tumour is usually suspected 
on the basis of abnormal heat patterns due to increased vascularization or 
asymetry. However, conventional thermography is unable to reveal any 
pathological signs in a large number of patients with carcinomas due to 
the fact that as many as 30% of carcinomas may not produce any heat and 
are of the same temperature as the surrounding tissue. 
Although it has been recognized previously that cooling, by evaporating 
alcohol from skin surfaces, and air conditioned rooms, may enhance 
thermographic images, such techniques do not provide precise regulation of 
temperature of the skin surface and underlying tissue to provide fine 
details. Although it has been recognized that cooling accentuates 
temperature differentials, the optimium cooling conditions have not been 
known. The use of cooling wraps were suspected of practical use, as 
evidenced by a paper entitled: "Temperature Measurements of Localized 
Pathological Processes" by R. N. Larson and J. P. Gaston, but have not 
been investigated substantially. 
SUMMARY OF THE INVENTION 
The present invention provides methods and apparatus for obtaining improved 
thermographic images through the use of controlled temperatures. 
Briefly, an embodiment of the present invention provides a method for 
conducting a thermographic examination of localized portions of the body 
including cooling the surface and underlying tissue of a localized area to 
15.degree. C. for five minutes. Affixing a liquid crystal film directly 
against the body. Cooling the liquid crystal sheath along with the 
localized area of the body for an additional 1-3, minutes again to a 
temperature of 15.degree. C. to insure that the film and the surface 
temperature are substantially uniform. Visual images on the liquid crystal 
film appear as a function of elapsed time as the body surface rewarms. The 
thermal images can be evaluated for irregularities which would indicate 
underlying pathological states. The time at which the visual images appear 
is an indication of pathological states. For example, in thyroid 
examinations visual images appearing before the normal three to four 
minutes is an indication of hyperthyroidism, visual images appearing after 
three or four minutes is an indication of hypothyroidism. 
The present method and apparatus need utilize a liquid crystal film of a 
single temperature range. Liquid crystal film usually is manufactured 
having a specific narrow range of temperature to which it is sensitive. In 
conventional thermography, the liquid crystal film must be selected on a 
trial and error basis until the film with the appropriate sensitivity is 
found. The present invention provides a method where the body surface and 
underlying tissues are cooled below the sensitivity of a liquid crystal 
film and then rewarmed such that the body surface temperatures pass 
through the narrow temperature range of the film providing details which 
conventional thermography has not been able to obtain. 
An embodiment of the invention further includes an apparatus for thermally 
controlling body surface temperatures. Briefly, the apparatus includes a 
pump in communication with a source of fluid of predetermined temperature. 
A reservoir adapted to be positioned in close proximity and in thermal 
contact with the body surface includes an input line and an output line. 
The input line is in communication with the reservoir, fluid source and 
the pump for receiving fluid and directing fluid into the reservoir. The 
fluid received by the reservoir is circulated establishing a substantially 
uniform temperature throughout the reservoir and underlying body surfaces. 
The output line is in communication with the reservoir for receiving fluid 
from the reservoir and returning it to the fluid source. The reservoir 
includes a layer of insulating material affixed to the side distal to the 
body surface to aid the reservoir in maintaining a uniform temperature. 
Straps are affixed to the reservoir for encircling portions of the body. 
The straps are provided with attachment means, such as loop and hook 
surfaces marketed under the trademark VELCRO, for securing the reservoir 
securely about the body surface. 
A further embodiment of the present invention utilizes air or other gases 
of predetermined temperature for controlling the surface temperature for 
localized portions of the body. Briefly, the apparatus includes a blower 
in communication with a source of air of predetermined temperature. An air 
tent, adapted to be positioned in close proximity and in thermal 
communication with the body surface, is in communication with the blower 
and air source by means of input and output lines. The air tent includes a 
flexible covering having a back panel, intermediate section, and a front 
panel. The back panel includes an opening adapted to substantially conform 
to the shape of the localized portion of the body. The back panel also 
includes a seal disposed around the edge surfaces to seal the covering in 
a substantially airtight manner against the body surface defining a 
chamber between the body surface and the covering. The input line is in 
communication with the source of air of predetermined temperature and the 
blower for receiving air and directing the air into the chamber. Air 
circulating in the chamber is of substantially uniform temperature to 
thermally control the temperature of the body surface. The output line, in 
communication with the chamber, receives air from the chamber and 
redirects the air to the air source. 
The air tent further comprises a temperature sensor, such as an infrared 
sensing probe in communication with the chamber to monitor the temperature 
of the air within the chamber, skin surface or target organs. A camera for 
recording thermographic images is placed in communication with an opening 
in the covering to receive and record thermographic images appearing on 
liquid crystal film or solution overlying the skin surface. A digital data 
logger may be utilized for recording temperatures. A video recorder used 
in conjunction with a television camera records visual images obtained in 
the thermogram. 
The present invention has particular application for performing 
thermographic examinations of the thyroid. Thus, an embodiment of the 
present invention further includes a liquid crystal sheath for use in 
thyroid thermography which is particularly applicable for use in 
conjunction with the cooling wraps disclosed herein. Briefly the liquid 
crystal sheath includes a sheet of liquid crystal film proportioned to 
substantially cover the front area of the neck. The liquid crystal film is 
substantially eliptical in shape to distribute stress equally about the 
film to provide a wrinkle-free surface. Four straps are affixed to the 
edge portions of the sheet for encircling the neck. The straps are 
arranged in pairs along the short lateral edge surfaces of the liquid 
crystal film. Each strap includes an elastic band extending from the far 
edges of the sheet and including hook and loop attachment surfaces, such 
as VELCRO, for attachment onto each other. The elastic bands secure the 
film firmly and resiliently to the neck while avoid stresses which would 
distort the film and alter thermographic images. 
The controlled regulation of temperature during the performance of 
thermographic examinations produces dynamic images. Differing tissues 
rewarm or cool at different rates producing images of both thermally warm 
and cold structures as the surface temperature of the skin and underlying 
tissue changes. The temperature of the surface of the skin can be adjusted 
to maximize the thermal images for clarity to the extend that the images 
frequently correspond to an anatomical and morphological structures. 
Structures can be selectively imaged by altering the surface temperature. 
Structures with the same surface temperature but differing cellular 
structures can be imaged separately due to differing cooling or rewarming 
rates. Such differing temperature cooling or rewarming rates are useful 
for differentiating functional state such as hyper and hypothyroidism. Due 
to the regulation of surface temperature, surface temperature variations 
and irrelevant information can be substantially eliminated. The use of a 
single type of liquid crystal film within a narrow temperature range can 
be readily selected without consideration of other environmental factors. 
Further, the present invention provides means to substantially reproduce 
thermographic examinations under controlled conditions allowing the 
monitoring of treatments or pathological progression. 
Other features and advantages of the present invention will be apparent 
from the following description and claims and are illustrated in the 
accompanying drawing, which by way of illustration show a preferred 
embodiment of the present invention and the principles thereof in what is 
now considered to be the best mode in which to apply these principles. 
Other embodiments of the invention employing the same or equivalent 
principles may be used and structural changes may be made as these are to 
those skilled in the art without departing from the present invention and 
purview of the appended claims.

DETAILED DESCRIPTION 
The present invention will be described in detail as methods and apparatus 
for performing thermographic examinations upon the thyroid area of the 
neck and upon the breast and abdomen, due to the current interests and 
applicability of thermography to those areas. It is understood that the 
present disclosure is to be considered an exemplification of the 
principles of the invention and is not intended to limit the embodiment 
illustrated. In particular, the present invention has applications to 
other areas of the body as well. 
It has been recognized that cooling the surface of a body by various means, 
such as alcohol, cold environmental temperatures, or circulating air upon 
the body surface, may enhance thermal images. However, the narrow range of 
surface temperature which would produce the maximum temperature contrast 
between an object and its surroundings remained unknown. The cooling means 
of the prior art were also purely tolerated by subjects, particularly 
those sensitive to low temperature such as those afflicted with 
hypothyroidism. The present invention provides a precise regulation of 
local skin surface temperature and the underlying deep seated structures 
in order that optimal thermal images are obtained. For a localized area of 
the human body, each structure generally has a different thermal 
conductivity, a different surface temperature, a different depth and other 
differences which influence thermal examination. In order to separate 
thermal images of differing internal structures the present invention 
allows the temperature of the skin surface and underlying tissues of a 
localized area of the body to be selectively raised or lowered. Images of 
different tissues thereby appear in a predictable sequence. 
The thyroid gland is an ideal organ for thermographic studies because it is 
superficially located and richly vascularized. Referring now to FIG. 6, if 
the surface of the neck is cooled the skin temperature over a tumor will 
warm at a faster rate than normal tissue and muscle. Referring now to FIG. 
7 the maximum difference in surface skin temperature overlying muscle and 
tumors will appear predictably within three or four minutes, allowing one 
to obtain thermal images of maximum clarity which differentiate the tumor 
from surrounding tissue during that period of time. 
Further, controlled local cooling of the skin surface allows for the 
differentiation between tumors and cysts. Referring now to FIG. 8, where 
line B refers to the surface temperature over a tumor and line A refers to 
the surface temperature of a cyst, if the tumor and cyst are cooled 
uniformly to a temperature of 0.degree. C. then allowed to rewarm 
themselves by the core body temperature, the tumor will rewarm itself much 
quicker than the cyst. 
Liquid crystal elastomer sheeting typically has a temperature capability 
between 28.degree.-32.degree. C. At 28.degree. C. the color of the 
infrared thermography is dark brown, at 29.degree. C. red, at 30.degree. 
C. yellow, at 31.degree. C. green, and at 32.degree. C. blue. Returning to 
FIG. 8, at 14 seconds after rewarming the color of the infrared 
thermography will start to change. At 18 seconds the overlying skin above 
the tumor will warm to 32.degree. C. appearing blue on the liquid crystal 
film whereas the skin overlying the cyst with a temperature of 5.degree. 
C., is below the sensing ability of the liquid crystal film, remains black 
in color. It will take more than 80 seconds after rewarming before the 
skin surface over the cyst begins to change color and appear on the liquid 
crystal film. Thus, it is feasible to differentiate between a tumor and a 
cyst independent of their original surface temperature. 
Further, the elapse rewarming time before thermal images appear as an 
indication of pathological states. In a normal subject thyroid images 
having maximum clarity appear between three to four minutes. In 
hypothyroid subjects the elapsed time will be extended shortened. 
Turning now to an apparatus for performing thermographic examinations of 
the thyroid, an embodiment of the present invention includes a liquid 
crystal sheath for use in thyroid thermography which is particularly 
applicable for use in conjunction with the cooling apparatus to be 
discussed later in the application. Referring now to FIGS. 9 and 10 the 
liquid crystal sheath, generally designated 11, includes a sheet of liquid 
crystal film 13 proportioned to substantially cover the front area of the 
neck. The liquid crystal film 13 is substantially eliptical in shape to 
distribute forces equally producing a substantially wrinkle-free surface. 
For adults, the eliptical film 12 has a small diameter of approximately 
four centimeters in length and a long diameter of approximately eight and 
one half centimeters. The liquid crystal film 13 has short lateral edge 
surfaces 16, which can be squared off as shown, and long rounded top and 
bottom edge surfaces 17. Four straps are affixed to the edge portions of 
the liquid crystal film 13, arranged in pairs along the short lateral edge 
surfaces 16, for encircling the neck. Each elastic band 14 includes hook 
and loop attachment surfaces 15, such as those commonly marketed under the 
trademark "VELCRO", for affixing the elastic bands 14 onto each other in 
an infinitely adjustable manner. The elastic bands 14 are affixed to the 
film 13 by means of foam 18 and metallic fasteners such as staples 19. The 
elastic bands provide a firm yet resilient pressure on the edge surfaces 
of the liquid crystal film 13 to hold the liquid film 13 firmly and 
tightly against the skin surface of the neck. 
An embodiment of the present invention further includes an apparatus for 
thermally controlling localized body temperatures. Referring now to FIGS. 
1, 2 and 3, a cooling blanket for use in controlling the body temperature 
of the neck area for thyroid thermography is generally designated by the 
numeral 20. The cooling blanket 20 includes a flexible reservoir 21 having 
a proximal surface 29, for positioning in close proximity and in thermal 
contact with the body surface about the neck, and an opposite distal 
surface 30 away from the body. Extending laterally from opposite sides of 
the reservoir 21 is an input line 22 and an output line 23. Input line 22 
and output line 23 are in communication with the interior of the reservoir 
21. Input line 22 receives fluid of a predetermined temperature and 
directs the fluid into the reservoir 21 where it is circulated to obtain a 
substantially uniform temperature throughout before exiting through the 
output line 23. The input line 22 is provided with an input valve 24 to 
control the fluid flow and pressure through the reservoir. A small 
resilient input reservoir 26 is positioned in the input line 22 to absorb 
the pressure as the input valve 24 is adjusted and to reduce turbulence. 
Similarly, an output valve 25 is positioned in communication with the 
output line 23 to control the fluid pressure within the reservoir 21. A 
small resilient reservoir 27 is placed within the output line 24 to absorb 
changes in pressure and reduce turbulence. The input and output valves 24 
and 25 allow the pressure in the reservoir to be maintained at a level 
where the reservoir 21 compliant to conform to the surface features of the 
neck. Over-inflation of the reservoir 21 forces the reservoir 21 to ballon 
outward from the neck surface such that uniform temperatures are not 
obtained. If flow is insufficient, the reservoir 21 will not provide 
substantially equal distribution of fluid and will also result in 
nonuniform temperatures. 
A temperature sensing device, such as a thermister 28 is positioned about 
the proximal surface of the reservoir 21 to allow the monitoring of the 
body surface temperature while the cooling blanket is being worn 20. 
Referring now specifically to FIG. 2 where the cooling blanket 20 is 
depicted as worn by a subject 38 the electrical wire 28A leading to the 
thermister 28 can be seen protruding from the cooling blanket where it can 
be connected to the thermograph control equipment 40 depicted in FIG. 3. 
The input and output lines 22 and 23 respectively protrude outwardly from 
the cooling blanket 20 allowing the input and output valves 24 and 25 
respectively to be easily manipulated by an operator of the equipment. 
An insulating layer 31 is positioned upon the distal surface of the 
reservoir 21 to facilitate the maintenance of uniform temperatures 
throughout the reservoir 21. The insulating layer 31 can be extended in 
the forms of straps 34 fashioned to substantially encircle the next area. 
The straps 34 are equipped with hook and loop attachment surfaces, 
marketed under the trademark VELCRO, for attaching the straps 34 onto each 
other at an infinite number of positions to allow the device to be worn by 
subjects with differing size neck areas. 
Referring now to FIG. 3 an embodiment of the present invention includes 
thermograph control equipment 40. The thermograph control equipment 40 
includes a source of fluid 48, preferably water and glycerol proportioned 
in equal amounts, in communication with a pump (not shown) which pumps the 
fluid through input line 22 to the cooling blanket 20. Fluid flowing from 
the reservoir 21 into the output line 23 is returned by the output line 23 
to the fluid source 48. The thermograph control equipment 40 further 
includes an infrared sensor 43 for detecting the temperature of the neck 
surface and underlying tissue and a camera or other visual recorder 44 for 
recording visual images that appear upon the liquid crystal film. The 
thermograph control equipment 40 includes a data recorder 46 and timer 45 
for recording elapsed time of photographs and the temperature readings of 
the infrared sensing device. 
In utilizing the apparatus, the cooling blanket 20 is wrapped about the 
neck area and secured in place by attaching straps 34. Cooling fluid is 
circulated through the reservoir 21 by means of input and output lines 22 
and 23. After a predetermined temperature of the skin surface is obtained, 
preferably 15.degree. C., as indicated by the temperature sensing device 
28, the cooling blanket 20 is removed and the liquid crystal sheath as 
previously described is affixed about the neck area. The cooling blanket 
20 is once again applied to the neck area to bring the liquid crystal 
sheath and the local skin area again to a uniform temperature of 
approximately 15.degree. C. After the liquid crystal sheath and the neck 
area are recooled for approximately 1-3 minutes, the cooling blanket 20 is 
removed and visual images on the liquid crystal sheath are recorded by the 
camera 44 as the skin surface and underlying tissues rewarm. The elapsed 
rewarming time, visual images and temperature readings are recorded by the 
data recorder 46 at regular intervals as determined by the timer 45. 
Further embodiments of the present invention utilize air or other gases of 
predetermined temperature for controlling the surface temperature of 
localized portions of the body. Referring now to FIG. 4 an air tent 
apparatus generally designated by the numeral 60, is adapted to be 
positioned in close proximity to the body surface to circulate air of 
predetermined controlled temperature. The air tent 60 includes a flexible 
cover 69 having the following major elements: a back panel 68, a front 
panel 66, and an intermediate section 67 (not necessarily drawn to scale). 
The back panel 68 includes an opening 70 for exposing a localized area of 
the body surface when the back panel is placed in close proximity thereto. 
The back panel 68, front panel 66, and intermediate section 67 define a 
chamber 71 through which air of controlled predetermined temperature is 
circulated. An input line 62 is in communication with the chamber 71 by 
means of a porous tube 64 which encircles the front panel 66. The input 
porous tume 64 includes a plurality of holes 64a to distribute air from 
the input line 62 substantially equally about the front panel 66 with 
minimal turbulence. Air entering chamber 71 circulates towards the back 
panel 68 where it is received by an output porous tube 65 encircling the 
opening 71. The output porous tube 65 includes a plurality of openings 
(not shown) to receive the circulating air. Output line 63 in 
communication with the output porous tube 65 receives the air and shunts 
the air to the thermograph control equipment 40 equipped with a source of 
controlled temperature air (not shown). 
Back panel 68 is preferably formed of a resilient foam material which 
allows the back panel to sealably engage the body surface. Affixed to the 
back panel 68 are straps 74 through 76 to encircle the neck area and 
secure the back panel in sealing engagement with the body surface. Thus, 
straps 74, jutting horizontally from the upper portion of the back panel 
68, encircle the upper neck area. Middle straps 75, jutting laterally 
upward from the mid section of back panel 68, extend over the shoulder. 
Lower straps 76, jutting laterally downward from the back panel 68, wrap 
under the arm. Each strap 74-76 include hoop and loop attachment surfaces 
77, such as those marketed under the trademark VELCRO, to affix the straps 
74-76 onto each other to securely position the back panel 68 about the 
neck surface. 
Front panel 66 is provided with openings 66A and B adapted to receive an 
infrared temperature sensing device 43 and a television or photographic 
camera 44. A zipper 66C facilitates the positioning of the camera and 
infrared sensing device 43 in communication with the interior chamber 71. 
It will be recognized by those skilled in the art, that the camera and 
infrared sensing device need not be positioned in the front panel, but may 
be positioned anywhere in communication with the chamber 71 to observe 
thermographic changes in the liquid crystal film positioned upon the 
subject. It will also be recognized that although the covering 69 is 
referred to as being flexible and resilient, providing flexible 
lightweight equipment, rigid covers would operate in substantially the 
same manner and are considered within the purview of the present 
invention. It is also feasible to affix liquid crystal film across opening 
70 in back panel 68 to close chamber 71 incorporating the film into the 
cover 69. 
The air tent apparatus 60 allows the surface temperature of the skin and an 
overlying liquid crystal film to be controlled while simultaneously 
recording thermal images by means of camera 44. Thus, cryoscopic 
thermograph 40 includes a television screen for monitoring the 
thermographic images and an infrared temperature sensing device 43. An 
infrared temperature sensing device 43 available from Magna Instruments 
Corporation. The infrared temperature measuring device 43 is capable of 
sensing the air temperature within the chamber 71 or the temperature of 
the skin surface and the target organ of a subject wearing the air tent 
60. The temperatures of the air and the skin can be recorded on a data 
recorder 46 of the thermograph control equipment 40 while thermographic 
images are recorded upon a video recorder 51 and displayed upon a 
television screen 50. The use of the air tent 60 allows for a duplication 
of thermographic examinations with fine details in a controlled setting to 
allow the monitoring of treatment or pathological changes. The air tent 60 
allows thermographic images to be readily taken while the subject's skin 
is cooled or warmed. 
Referring now to FIG. 5, an air tent apparatus 60A, similar to that 
previously described, is illustrated for thermographic examinations of the 
chest and abdomen, and particularly the breasts. The modified air tent 60A 
similarly includes a front panel 66, an intermediate section 67 and a back 
panel 68 defining a chamber 71. Back panel 68 includes a more rectangular 
opening 70 to expose the breast and axillae to the view of a camera and an 
infrared temperature sensing device (not shown in FIG. 5) which can be 
placed in communication with chamber 71 by means of openings 66A and B in 
front panel 66. 
Preferably back panel 68 is formed from a foamed resilient material which 
allows the back panel to be placed in sealing engagement against the body 
surface. The back panel 68 is held securely in engagement with the body 
surface by means of straps 74, 75 and 76. Middle strap 75 includes a 
triangular portion 78. The triangular portion 78 extends substantially 
from the upper and lower areas of the back panel 68 and narrows to form 
the strap 75 to distribute stress equally about the back panel 68. Straps 
74, 75 and 76 include hook and loop attachment surfaces about their length 
for affixing the straps onto each other to encircle and secure the air 
tent apparatus 60A about the upper body area. Input line 62, input porous 
tube 64, output line 63, and output porous tube 65 act similarly to the 
air tent 60 described in FIG. 4, to blow air of controlled predetermined 
temperature into the chamber 71 by means of the input line and input 
porous tubes 64 circulating the air, circulating the air towards the 
output porous tube 64 where the air is received and shunted by output line 
63 back to the source of controlled air within the thermograph control 
equipment 40. 
Preferably in using either of the air tent apparatuses 60 or 60A air 
circulating within the system is dehumidified so as not to interfere with 
infrared temperature reading or with thermographic readings. Preferably 
the infrared sensing probe measures and monitors the temperature of the 
target organ and the temperature of the cooling blanket or skin surface. 
The rate of temperature change during the procedure is continuously 
monitored and recorded in a data logger 46 equipped with a printer. Data 
loggers 46 are available from companies such as Electronic Control Design, 
Inc. or Minilogger. The camera should have a macrolens and low light 
capability. Liquid crystal film is inherently shiny creating problems in 
lighting. Preferably a cross field polarizing light should be used. 
Thus, the present invention includes methods and apparatus for performing 
thermographic examinations which can be readily reproduced to monitor the 
progression of treatment or disease and yet is inexpensive, very rapid in 
obtaining results, and simple in operation. Thus, while the preferred 
embodiment of the present invention has been illustrated and described, it 
is understood that it is capable of variation and modification and should 
not be limited to the precise details set forth, but should include such 
changes and alterations as fall within the purview of the following 
claims.