In case you are reading this article in a standing position, a plume of turbulent air would be swirling around your shoulders and climbing about 6 feet above your head. Even this plume cannot be seen by the naked eye. It can however be perceived by a special camera to be twisting and flickering like the flame of a candle—considering you are a wick. Scientists believe that each plume is unique to an individual and its characteristics depend to a large degree on the individual’s physical state. An examination of the plume—a new technique in the science called ‘Aerobiology’—can tell doctors a great deal about how a particular person is feeling and why he is feeling that way.
This is one of the techniques of aerobiology designed to ‘read’ the heat radiations of the body. Such techniques can indicate whether someone who claims to have a chronic headache is really suffering. Some researchers feel that they can help identify doctors who should not become surgeons. They may also explain why human beings have a poor sense of smell. They can help police to locate graves of murder victims; a decomposing body shows up hotter than the surrounding soil.
Aerobiology is non-invasive—there is no X-ray—no taking of blood sample, no probing flesh or bone for specimens. Thus aerobiology promises to be a new tool that will aid quick, safe inexpensive medical diagnosis.
The development of aerobiology’s newest technique goes back to about five decades. One day a British physician Harold Lewis was visiting an aircraft testing centre. There he saw a demonstration of Schlieren photography, an optical technique that makes flow of air across an aeroplane body in a wind tunnel visible. Schlieren photography was invented 100 years ago in Germany.
During the wind tunnel demonstration a technician accidentally happened to stick his hand into a beam of light used in Schlieren photography. Dr Lewis noticed that the camera had recorded the man’s palm and fingers as solid black but he could also see long greyish wisps of air rising smoke-like from the man’s finger tips; the man’s body heat was rolling the air around his hand! In a flash Dr Lewis saw a potential use for the camera in studies of human beings and he obtained a Schlieren system for his own laboratory.
By the early 1970s Dr Ray Clerk who was associated with Lewis began to investigate the body’s turbulent plume. The plume was not merely an interesting phenomenon but turned out to have important and surprising ramifications. For example the plume explains why string vests keep arctic explorers warm and how long robes keep an Arab cool.
Clerk believes that Schlieren photography can tell us why some people regardless of ability should not be allowed to become surgeons. Within the plume are thousands of human skin cells and bacteria all continuously slighted off by the body. Among normally healthy people, this human floatsam poses no serious problems but 3 per cent of the population produces a strain, of bacteria that could really produce serious infections if they come in contact with a patient’s wound while on the operation table.
A few years ago, Clerk used his knowledge of the body’s heat distribution to make patients in a hospital more comfortable and also to save money for a hospital. He found that the new air-conditioning system located in a ward filled with seriously-ill patients was circulating air at a brisk rate. This flow of cold air was tolerable for the staff since they were standing up and had their warm six- foot heal and shoulders plume to act as buffers against the cool air. But for the ward patients who were lying horizontal with their body heat distributed weakly along their bodies the cool air flow had a distinctly chilling effect. The hospital could have heated the air, but this would have been expensive and would have made conditions uncomfortably warm for the staff who were in standing position. Clerk’s solution was simply to reduce the intensity of air flow in the ward. When the body is horizontal the body heat plume rises a mere two feet and the head is the major loser in the process. No longer insulated by its normal six-foot plume it loses 30 per cent more heat than it does when the person is standing up. Hence, a person would do well to wear an old fashioned night cap.
On the other hand the nose may be winner when the body is horizontal. When the body is erect it is enveloped in a cloud of the body’s debris. Clerk wonders whether this would explain why Homosapiens have lost so much of their sense of smell.
In addition to Schlieren photography another big weapon of aerobiology is the thermovision camera that gives doctors glowing colour photos of the way heat loss is distributed across the body. Thermovision also allows the trained eye to recognise body heat patterns.
Thermovision was originally developed by the military to detect enemy snipers by picking up an image of the heat given off by their bodies. It had originally been felt that thermography could be used as an early warning system for detecting ailments such as breast cancer because tumours tend to be slightly warmer than the surrounding tissues and thus show off.
But thermography did not appear to be much of an improvement over conventional cancer-diagnosing methods in the absence of basic research regarding heat process in the body. Clerk’s findings, however, have important implications. Firstly, there is a constant shifting and changing of temperature levels over the entire body surface. Secondly, on the video screen of the thermographic camera this shifting can be seen as vivid colourful patterns! They ebb and flow as different parts of the body heat up and cool down. Doctors are hopeful that thermography will help in isolating ‘partakers’ from patients who are actually suffering from physical illness because truly painful areas tend to show up in thermograms clearly. Despite the early set backs in diagnosing breast cancer thermography has already been successfully used as look-out system for blood clots (deep vein thrombosis).
A thermographic comparison of a person’s leg can show up a telltale area while a clot is in the process of forming.
A thermographic reading may become routine for patients in the future. Unlike the X-ray and other exploratory techniques, the process will carry no disability cumulative doses or side-effects. Part of its utility value will be its ability to pinpoint patients who seem likely to be predisposed to certain conditions.
A patient ear-marked for a hip operation would be screened to see if he or she is pre-disposed to blood clots—a possible side-effect of the operation. Elderly patients would be routinely checked to see if they were susceptible to hypothermia. children prone to obesity could be spotted early.
It should be possible to monitor post-operative therapies. The progress of a patient recuperating from a serious operation or an accident could be objectively measured. This would allow for more focused use of physiotherapies. Thermograms can also reveal how much of the rheumatic inflammation had been reduced by drug treatment. This permits different kinds of treatment to be compared. Thus the non-invasive investigation of thermography and Schlieren photography on the frontier between our bodies and the outside world is expected to produce far reaching effects on our lives and our health.