Frequently Asked Questions About Thermography

Q. What is DITI?

A. DITI, or ‘Digital Infrared Thermal Imaging’ is a non-invasive imaging technique for measuring and displaying changes in skin surface temperature to a very sensitive 0.05 degrees centigrade. An infrared scanning device is used to convert infrared radiation emitted from the skin surface into electrical impulses that are visualised in colour on a monitor. This visual image graphically maps the body temperature and is referred to as a thermogram. The spectrum of colours indicates an increase or decrease in the amount of infrared radiation being emitted from the body surface.

Since there is a high degree of thermal symmetry in the normal body, subtle abnormal temperature asymmetry’s can be easily identified.

As tumours emit more heat than their surrounding tissues and over time stay hot or become even hotter, thermal imaging is a sensible method of detecting such early changes and risk factors. DITI therefore is ideal and excellent for measuring the extent or degree of “activity” within a given area. Areas that measures too hot or even too cold are noted as being early warning signals of something potentialy sinister in the underlying tissue.

Q. What is DITI unable to show?

A. DITI is not able to show clearly details of anatomical structures within the body. These are better shown with ultrasound, MRI and X-rays.

Because DITI is a measure of function rather than anatomical structures, DITI may not always show for example the presence of a lump, if this lump is benign, quiet, non invasive or not active. A lump does not always necessarily mean it is cancerous or active.

Q. Are there any contra-indications to having DITI?

A. None - the procedure is non-invasive, non-contact and uses no radiation.  As such it is also perfectly safe to use during pregnancy, although breast images will be affected by the hormonal changes within about 48 hours of conception and will not return to a stable thermal fingerprint until about 3 months after the end of lactation. After this point, Thermal scans can resume as normal.

Q. Do I need a referral from my Doctor?

A. No, it is not necessary to be referred by your doctor, although many practitioners are now recognising the importance of DITI as valuable method of testing and monitoring, and do refer their patients to us.

All you need to do is call on 02 6655 9400 or 1800 000 877 to make your appointment.

Q. Can DITI diagnose cancer?

A. Thermal Imaging, mammography and ultrasounds are not diagnostic tests. Thermal Imaging is an objective test measuring skin surface temperature to a very sensitive and accurate degree reflecting changes in physiological and metabolic activity within the underlying tissue area. While breast cancer can only be truly diagnosed by tissue biopsy, breast thermography safely eliminates the need for most unnecessary biopsies as well as the associated high cost and emotional suffering, and it does so years sooner than any other test in modern medicine.

Q. How else can DITI help?

A. An Infrared camera takes a thermal image. Inflammation shows as hotter than normal tissue around the problem area, and you can clearly see the inflammatory patterns with your own eyes.

In the photo above the red line you see on the neck is a major artery to the brain (carotid artery) that is hotter than it should be (inflammation). Next to it is a picture of someone whose artery is normal. This is a safe way to see what is going on inside the body from the outside. When there is inflammation in this artery, there is a good chance that other arteries in the body are also inflamed, not just the carotid artery.

Now look at this Infrared picture of a woman with a very early stage of breast cancer. The arrow shows where the cancer cells are located. Around it you can see the heat it creates as well as the vein that delivers blood to the area so it can grow (without a blood supply it would die). This new blood supply is called angiogenesis.

What’s so amazing is that these conditions can be seen many years before a person has symptoms, long before it is normally detected with other kinds of diagnostic tests and also long before irreparable damage is done.

Everyone should have these images taken - they save lives!

Q. In relation to breast scanning, when should women start using DITI?

A. With the rising incidence of breast cancer in younger women it really is important to begin breast cancer screening long before 40 years old. It should begin at the age of 25 in order to identify young women who are already developing breast cancer since most breast cancers do not become palpable until they are greater than 1cm in size - by that time 25% have already spread to other parts of the body (metastasised).

Because most lethal breast cancers take approximately 15 years from their beginning to the time of death, women need reliable testing that starts when the cancer is initially forming - in their mid-twenties.

Another reason to start screening earlier is that young women with dense breast tissue are the most difficult to evaluate using breast palpation, mammography and ultrasound examinations, yet their significantly higher risk of developing breast cancer can be accurately detected with breast thermography.

Who certifies your thermographers?
A. Meditherm provides technician training courses at Duke University that are approved by the American College of Clinical Thermology Inc.

Q. Do you have to be a doctor to operate the camera?
A. No. Anyone with computer skills can be trained as a thermography technician.

Q. Who interprets the images?
A. As part of the Meditherm system we have access to an online interpreting service that is staffed by board certified MD’s who are also fully trained in image reporting through the American College of Clinical Thermology Inc.

Q. When I have my Initial Breast Scan, why do I need to come back in three months for another breast study ?
A. The most accurate result we can produce is change over time. Before we can start to evaluate any changes, we need to establish an accurate and stable baseline for you. This baseline represents your unique thermal fingerprint, which will only be altered by developing pathology. A baseline cannot be established with only one study, as we would have no way of knowing if this is your normal pattern or if it is actually changing at the time of the first exam. By comparing two studies three months apart we are able to judge if your breast physiology is stable and suitable to be used as your normal baseline and safe for continued annual screening.
The reason a three-month interval is used relates to the period of time it takes for blood vessels to show change…… a period of time less than three months may miss significant change…….. a period of time much more than three months can miss significant change that may have already taken place.
There is NO substitute for establishing an accurate baseline. A single study cannot do this.

Q. Where does the Meditherm camera used by Thermal Scans come from ?
A. First, the Meditherm camera is manufactured in the USA and is fully compliant as a medical device with the FDA, and also the TGA here in Australia.

Q. Why doesn’t the Meditherm camera measure from 0 to 300° C?
A. Because we have optimized for sensitivity within the range of human physiological temperature.

Q. What is the difference between high definition thermography and other types ?
A. Just about all modern cameras provide high-definition images.  The ‘definition’ of a thermogram relates to how many individual temperature measurements are taken to build the image. The actual definition is not as important as how accurate and sensitive those temperature measurements are. The higher the definition, the better the picture will look but this does not mean that the accuracy is any better.
Describing a thermogram as ‘high definition’ maybe confusing and misleading as most so-called high-definition images are produced by software manipulation of the data.
Low definition would be considered below 160 x 120 pixels. Industry standard is between 160 x 120 up to  320 x 240 pixels. High-definition would be considered above this and can be as high as 640 x 512 pixels.

Q. Everybody talks about resolution. What is resolution? Is resolution important?
A. First, there are a couple of resolutions that apply to IR cameras. There’s spatial resolution and there’s thermal resolution. Spatial resolution is related to the number of pixels in an image. This is analogous to today’s digital cameras and their number of pixels/picture, e.g. 2 megapixel vs. 3 megapixel vs. 4 megapixel, etc. For many or most applications 2 megapixels will provide excellent pictures for most settings in fact unless you try to zoom in you would be hard pressed to tell the difference between 2, 3 or 4 megapixels. However, you will find a significant difference in image file sizes and camera costs. The point here is that the 2 megapixel camera will work perfectly well for routine picture taking. Using IR cameras for scanning humans works much the same way. The human body doesn’t exhibit significant temperature changes over very small areas. The skin tends to form a continuous surface and heat spreads out smoothly over large areas. In fact research has shown that good pattern recognition could be performed with IR cameras having resolutions as low as 160 pixels by 160 pixels ( total pixels~26,000).

Thermal resolution is a measure of a camera to detect very small temperature differences. Say for example one wanted to see 0.25 ° C differences on a surface, you would need a camera capable of detecting much smaller differences. As a practical matter, the human body has a typical surface temperature ranging from just over 30 ° C to around 38 ° C. Temperature variations on an individual will fall into that range of temperatures. Meditherm cameras are optimized for viewing this temperature range. The color scale is set so that maximum contrast can be achieved to show findings that relate to pathologies that would not otherwise be seen.

Want smooth images- use 256 color steps.
Want maximum contrast use 8 degree C range and 16 color steps.

Meditherm’s extensive testing protocols are designed to work with the 8 degree thermal window and 16 colors of the ‘Medical Map’.

Q. I was told that grayscale thermograms were higher resolution than color, why don’t you show grayscale ?
A. Nowadays there is no difference in resolution between color and grayscale with modern digitized images. When images were viewed on an old TV screen, it took three phosphors on the cathode ray tube to make one color dot….. it only takes one phosphor to make a shade of grey, the resolution in black and white therefore, would be three times greater than it was in color.

Q. I notice some IR cameras use many more colors in their displays. How come Meditherm only uses 16?
A. We do give you the choice of many different color displays including the ‘smooth’ looking 250 color scale. Our default color scale uses 16 colors that make visual identification of temperature differences easier and enhances pattern recognition.

Q. I recently saw a camera that had a real fast scan. Yours doesn’t. What’s the difference between that one and the Meditherm DITI?
A. There is a trade off between speed and sensitivity / accuracy which applies to all systems. The Meditherm Pro system uses two scanning speeds that give the best combination of speed, sensitivity and accuracy so you don’t have to pay for speed that you don’t need! The Meditherm IRIS system does deliver real time speed (30 frames per second) and provides sufficient sensitivity for medical imaging.

Q. What’s the difference between a scanning camera and a focal plane array camera?
A. There are several broad categories of imagers. They can be lumped into groups as follows:

Single detector/scanning systems, scanned/linear array and staring or focal plane array. Each has characteristics somewhat unique to itself, but each can be made to read temperatures (radiometric).

Scanning systems use a single detector and have a scanning mechanism in the optical path which allows an image to be constructed. A major benefit to this approach is that the single element is making all the measurements. Differences in element sensitivities or bad elements, which occur in focal plane array devices, don’t occur thus thermal uniformity is quite good. The downside to scanning cameras is they take longer to image, but for stationary objects where temperatures aren’t changing rapidly (as with medical imaging) this is a non-issue.

Focal Plane Array or staring array cameras (FPA’s) have the benefit of providing fast scanning. Images are formed in “real-time”. Each element in the detector array corresponds to a pixel element in the displayed image. Until recently, FPA’s required cooling to be useful. Liquid nitrogen was used for a long time. Today closed cycle Sterling Coolers are frequently employed. Downsides to these cameras are expensive replacement cost for coolers and the fact that there are dead pixel elements and different sensitivities across the detector which must be compensated for (or assigned a value).

A new type of FPA, one that doesn’t require the Sterling cooler, is becoming more popular. This is known as the micro-bolometer. It has the same issue with dead or lower sensitivity elements. This type of detector is really a hybrid of the other two. It uses a linear array, offers higher scanning speed than the Scanning detector, but considerably slower than the Focal Plane Array detectors. To some degree it suffers from the bad pixel syndrome but since there are fewer active elements it’s a smaller issue. It also needs a cooler, which can be a costly maintenance item.

The third style, the linear array, uses a line of detectors which are scanned. This is a cross between a scanned single element and a focal plane array. It provides marginally faster scans but also has some of the same bad pixel issues. Currently, linear array cameras use detectors that require mechanical coolers or use Liquid Nitrogen as the cooling element. Images, after averaging, can be quite good.

Both FPA’s and Linear array cameras have noisier displayed images and are generally averaged before saving an image. Signal averaging ads to the overall acquisition time thus reducing the seeming advantage over scanning systems.

Q. Is system stability important?
A. Yes! Stability is the characteristic in a system that allows you to accurately perform comparative studies over time …. (minutes / hours / weeks / years) to detect any changes . It is because the Meditherm camera has such excellent stability that screening breast studies can be performed with confidence; it is due to this stability that certified thermologists (MD’s) can reliably analyze images statistically and provide reports to the thermographer.

Q. I hear from some people that you need to “cold stress” the patient. What is “cold stressing? Do I really need to do it?
A. Cold stressing is a test to measure sympathetic function, It is a useful test for a number of conditions including RSD (CRPS). Protocols used with the Meditherm system for breast screening do not require routine cold stressing but it may be requested by a referring physician or reading thermologist.