With the recent interest in breast thermography, some commercial equipment manufacturers have begun developing and marketing new technologies aimed specifically at this market.
Unfortunately, this has led to a variety of manufacturers claims as to the "superiority" of their particular technology, often without a legitimate basis.
It is our sincere wish that continued advancements in this technology will be made in an effort to save more lives. However, there are some who are misleading the public with unproven, and possibly detrimental, technologies. Qualified clinical thermographers, certified through a recognized agency, are familiar with the scientific literature and the technologies involved and have the experience to determine the validity of such claims. Unqualified thermographers and technicians, however, may simply accept these claims at face value and pass it on to the general public as fact. Since this can be extremely confusing for a patient simply attempting to find a thermography center, we offer this section as an aid to separate the fact and fiction in some of the claims we have heard regarding "new" thermographic technologies. This also applies to physicians and technicians attempting to enter this field.
New Forms of Infrared Imaging Equipment
There are many very high quality and acceptable thermography systems on the market. There are also some that appear promising, but are not proven. A few systems also incorporate questionable procedures that may prove detrimental to the patient by providing incorrect data. Then there are those that have been long abandoned by the thermographic community. The following information will be confined to the use of thermographic equipment for breast cancer screening.
Currently, there are some manufacturing companies making claims that their product is superior to the infrared imaging systems of the past. Are these new infrared imaging systems capable of "seeing" more? Sometimes yes, but sometimes no. Is seeing more thermal data diagnostically superior? No one knows at this time. There is no research to substantiate any of these claims.
One cannot compare a thermodynamic imaging procedure (thermography) to the simple principles of X-ray (i.e. mammography) where seeing more is definitely better. Well over 99% of the research found in the literature, all the large-scale studies, and all the current standards and protocols were performed using first and second generation infrared imaging systems. And as such, breast thermography has been proven as a valid and accurate procedure having a sensitivity and specificity of 90%. The bottom line is research.
Until enough valid research is performed using new technologies, the equipment and methods will remain investigational. Manufacturers and supporters of these new systems must meet the same research standards used in previous thermographic studies if a valid comparison is to be made. A study comprising a sample of 20,000-30,000 women observed over 5-10 years would yield enough data to draw valid conclusions concerning a new technology. Also, if any new form(s) of interpretation (computerized or manual) are involved, the studies will need to use at least 2 experienced board certified clinical thermographers reading the same exams in order to evaluate the new method(s) used.
When this data is compiled and published in a peer-reviewed index-medicus journal, those of us who provide this critically important service to women will be able to make an informed decision as to whether or not this new technology yields any additional benefit to the patient. This is the only proper way to evaluate any new procedure or equipment used in the health care field.
As a consumer, the best way to protect yourself from these sales tactics is to look to the personnel who are performing and reading your scans as a guideline for proper thermographic imaging. As long as the technician and interpreter are board certified by a reputable agency, their level of instruction is intended to protect the patient by providing them with accepted infrared imaging standards which includes proper equipment selection and imaging protocols.
Specific Equipment Types
There are two very basic categories of thermal imaging devices: contact and non-contact. Contact devices, as the term implies, are touched directly to the skin. Modern infrared camera systems are of the non-contact type.
Due to certain inherent errors involved with contact devices, their use has basically been discontinued. However, there are two types of direct contact thermographic devices currently produced: Liquid Crystal and Thermocouple. Liquid crystal systems have merit while the recent resurrection of thermocouple systems (1940s technology) is problematic. The following is a simple overview of the reasons why modern infrared imaging systems have replaced these outdated devices.
Liquid Crystal Thermography (LCT)
These devices are currently being phased out in today's clinical setting. This does not mean that they are not accurate in the hands of a Board Certified Clinical Thermographer, but the technology is old and incapable of discrete objective thermovascular analytical procedures afforded by modern computerized systems.
A LCT system includes a set of flexible temperature sensitive liquid crystal plates that are supported in a frame. This frame holds the plates firmly in place allowing the clinician or technician to push the plate against the breasts. The plates are imbedded with a mixture of organic crystals, which when activated by the heat of the body emit visible light in varying colors allowing accurate temperature measurement. A camera is also mounted on the frame for photographic recording of the examination for analysis. Keep in mind that in the hands of a highly trained clinical thermographer, this system produces very good quality diagnostic thermograms. Systems have been sold worldwide and used by universities, hospitals, and private practice clinicians.
There are several concerns surrounding the actual contact with the breasts:
- That the actual touching of the breast might produce a sympathetic reflex response in the patient, thus altering blood flow to the breast and changing the actual temperature.
- That accurate temperatures cannot be measured. A temperature or color scale is provided on the side or bottom of the detector plates, which closely match the colors of the crystals. However, there is some overlap in these color scales, which makes actual spot temperature (accurate quantitative analysis) readings impossible.
- Two objects of differing temperatures, when brought into contact, will attempt to reach thermal equilibrium (Zeroeth Law of Thermodynamics), thus changing the actual temperature of both objects. The detector plates being of room temperature, and thus much colder than the skin, when brought into contact with the breasts will change the factual temperature of the skin and thus the true thermal data being analyzed. In an attempt to compensate for this, the liquid crystal plates are designed to react (develop) very quickly. However, contact has been made leaving question to the amount of data change.
While infrared cameras are superior to LCT, the technology provides a very good and inexpensive screening tool for the average office.
The reputable thermographic community has abandoned these devices on an international level. Early research performed in the 1950s used thermocouples, as reliable infrared camera systems had not been invented yet. Most of these devices are composed of a hand-held device with a heat sensitive metal sensor called a thermocouple at the end.
The thermocouple device is touched to the skin and temperature is recorded either by reading an analog meter, a liquid crystal display, or by a computer program. Of concern is the current resurrection of these devices marketed as a superior form of thermography. Some health care providers are using these systems within their specialties, but research on the reliability and clinical utility of these devices remains lacking, and in some cases, spurious. Some manufacturers have been marketing that thermocouple "thermography" is proven by thousands of research studies, but neglects to inform the public that these studies were performed with infrared camera systems and not thermocouples.
We have also seen some of these devices marketed as "new thermography" with FDA approval. It is unfortunate that the general public and untrained health care practitioners have become the target of aggressive marketing.
The concerns with this technology are some of the same as with LCT. However, the problems are so significant with thermocouple devices that the technology has been abandoned.
- Accuracy: Two objects of differing temperatures, when brought into contact, will attempt to reach thermal equilibrium (Zeroeth Law of Thermodynamics), thus changing the actual temperature of both objects. The thermocouples being of room temperature, and thus much colder than the skin temperature of the breasts, when brought into contact with the breasts will change the factual temperature of the skin and thus the true thermal data being analyzed. Unlike LCT, thermocouples react much slower; thus necessitating a longer contact time with the skin. This longer contact time increases the temperature change in the skin further decreasing the accuracy of the reading.
- Thermal carry over: Once touched to the body, a metal thermocouple retains heat from that area. When applied to another area of the body, the warmed thermocouple changes the temperature of the skin; thus giving a false or artificial reading (thermal carry over). An example of this would be in examining for a difference in temperature between the two nipples. Let us assume that the right nipple is slightly warmer than the left. The right nipple is measured first, and then touched to the left. The carry over heat pattern may make the left nipple appear warmer than it actually is, and thus the difference between nipples might appear normal when indeed a serious pathology is present. The cooler and normal nipple would simply appear warmer and closer to the temperature of the affected nipple because of the carry over.
- Poor Resolution: A significant failing of these devices is the general lack of target sensitivity related to body mass. These devices are very small typically measuring only a few millimeters of skin tissue. When applied to the skin, a few measurements are taken off of each breast. Modern infrared thermographic cameras measure and make composite maps of tens of thousands of data points on each breast, without contacting the patients body. The important diagnostic information that is missed by these devices is completely unacceptable to modern clinical practice.
We hope that this information has been helpful. If you have any further questions, please feel free to contact us at firstname.lastname@example.org.