As a committed health care provider, you have probably been introduced to medical Infrared or thermology at one point in your career. Today, Infrared is becoming widely accepted as one of the more sensitive and objective tools for medical assessment and diagnostics.
As a medical science, Thermology was first documented around 400BC by Hippocrates. He wrote "In whatever part of the body excess of heat or cold is felt, the disease is there to be discovered". In his time, Ancient physicians of the Golden Age were known to employ a primitive form of Thermology where they would apply thin mud slurry onto their patient's body. As the compound dried, patterns of hot and cold would emerge by different rates of drying.
While the science continued to evolve with varying degrees of progress, the next really big breakthrough wouldn't come until much later, when a scientist named William Hershel, experimenting with prisms to separate the various colors of visible light, discovered a measurable temperature change in each color of the rainbow, a pattern that extended to a curious place well past the color spectrum. Dr. Hershell had discovered what we now refer to as infrared radiation. Infrared, meaning "below the red", describes a specific span of the electromagnetic spectrum, which is a scale used to classify various forms or radiating energy.
As a natural effect of metabolism, humans are constantly releasing varying levels of energy in the infrared wavelength; thisinformation can be expressed or measured as heat. To learn more about some of the physical fundamentals behind infrared, visit History Of Infrared.
While Hershell's and several subsequent breakthroughs including Albert Einstien's later theory of the photoelectric effect certainly helped to expand our understanding of the physical fundamentals of infrared energy, applied thermology didn't really move into the arena of medical imaging as we know it today until the late 1950's when U.S. military defense projects pioneered a new way to capture infrared (temperature) information by using electronic infrared imaging cameras. These modern devices revolutionized the science and quickly replaced many of the more primitive forms of temperature measurement such as contact thermometers and liquid crystal thermometry.
The advantage to these new imaging devices was that they could provide a way for physicians to instantly capture large arrays (images) of quantitative thermographic or temperature information. Within a decade or so of the technology's release, the basic clinical principals of thermology were defined and several major clinical trials were under way. In this image, each pixel represents a different temperature.
For example: the new Eclipse infrared imaging system by Bright provides a 320x240 pixel resolution, this means each image contains 76,800 separate points of recorded temperature data in each image.
Throughout the 1960's and 70's modernized physicians began to utilize the new infrared imaging technology at their disposal. These thermologists were accomplished experts in their respective fields of breast oncology, vascular medicine and neurology; they worked in specialty centers with a multi-modality approach to diagnostic medicine. Their early work was a great undertaking to refine a number of emerging clinical applications. Of the many being scrutinized, a few quickly accumulated more research than others and as the science progressed infrared mammography quickly took the spotlight when breast oncologists discovered that the infrared mammograms or breast thermograms of women with malignant breast tumors characteristically presented abnormal, high energy blood vessels approximating the tumor.
The first meaningful large-scale study designed to investigate these findings took place at the Cancer Institute of Pasteur University in Marseilles France. This retrospective study was published in 1975 and took place in a comprehensive multi-disciplinary center. The study incorporated the experience of tens of thousands of case studies over many years and the results yielded the first objective criteria for the analysis of infrared images for breast oncology.
For details or to download the study, visit Research.
While the study was praised for quantifying the importance of high energy vascular like features as a diagnostic characteristic of infrared imaging for breast oncology, it didn't fully explain their origins. Coincidentally another significant work, also published in 1975 had an answer.
The publication was Judah Folkman's theory of neo-angiogenesis of solid malignant tumors. Folkman's theory offered a rationale for the important association of atypical vascular like features in infrared breast oncology.
His theory proposed that tumors in the early stages of development, would initiate the growth of their own atypical vascular networks in order to provide certain essential nutrients required for rapid growth and even metastasis. Dr Folkman's theory also helped to explain the abnormally high heat/energy levels or metabolic activity coming from theses atypical venus structures, he proposed that as a byproduct of angiogenesis, the tumor released nitric oxide which acted as a potent vasodilator; in essence nitric oxide disabled normal healthy vasoconstriction of blood vessels local to the tumor which of course increased blood flow and therein, heat. Now thermologists understood that the hotter more metabolically active vascular features they found to correlate to early stage breast cancer were indeed inherent to neo-angiogenesis.
For details or to download the study, visit Research.
In the late 1980's, following Dr Folkman's important discovery of neo-angiogenesis a group of German anatomists from the University of Essen in Germany demonstrated the primitive lacunae structure of neo-angiogenic vessels and their lack of a regular endothelial layer and complete lack of vascular smooth muscle. These unique features meant that neo-angiogenic vessels could not respond to physiologic modulation by the autonomic nerve system. In essence, when the body is exposed to certain environmental changes an autonomic nervous response is triggered to either constrict or dilate the body's blood vessels.
What the researchers in Essen had found was that unlike all other venus structures in the body, angiogenic blood vessels cold not respond to cues of the autonomic nervous system. Therefore, if the body was exposed to cold, for instance, all the body's blood vessels would constrict except for those formed by tumors. This discovery had profound implications in thermology. Now thermologists had a way to more clearly distinguish the difference between healthy blood vessels and those formed as a result of angiogenesis.
The process was coined 'the cold challenge' and the procedure was simple. Physicians would first capture a baseline set of infrared images in an array of angles. Next the patient is instructed to place their hands in a shallow pool of cold water (approximately 53° F) for one minute. Finally, a second set of post challenge images are captured in the same array of angle as the first. By comparing the two sets of images infrared analysts could easily distinguish between vascular networks that responded to the challenge and those that didn't.
Today, modern thermology is a highly refined science with standardized applications in Neurology, Vascular Medicine and Breast Oncology. Thermographers have access to incredibly precise FDA approved digital imaging technology at specialized centers around the world.
While some centers may choose to conduct image analysis internally, most outsource to infrared reading labs. Analysts at these facilities use highly refined techniques and software tools to conduct diagnostic analysis and document findings.
Currently the standard for objective analysis is the Marseilles system, which was named after its early pioneers, a group of researchers at Pasteur university in Marseilles France who, in 1974 conducted one of the most influential diagnostic studies of thermology ever known. While the system has been refined with a greater understanding of human physiology and increased clinical experience it remains the basis for the diagnostic breast thermology to this day.
To learn more about infrared analysis and the Marseilles analytic system, visit Understanding Image Analysis.