Thermography Myths

No! And this issue needs to be addressed. Patients are being scared and spending thousands of dollars on unnecessary dental procedures and thermograms.

Here are the simple reasons that none of this is possible:

1. Due to the Zeroth Law of Thermodynamics, the lymphatic vessels are invisible to thermography.
2. No lymphatic vessels lead from the face to the breast.
3. The normal immune response does not allow an infection to move all over the body – it walls it off.
4. There is no image on a thermogram alone that can be identified as lymphatic congestion or a lymphatic vessel.

Let’s start with the thermograms being seen on the internet. These thermograms show a hot “vessel” or “vessels” leading down from the side of the face, over the front of the neck, and down into the breast. This is assumed to be a lymphatic vessel(s) – error number one. 

• All lymphatic vessels drain UP from the breasts. The right breast draining into the right lymphatic duct at the subclavian vein and the left breast draining into the left thoracic duct at the left subclavian vein.
• All the lymphatics from the face drain DOWN and into these same ducts.
• Lymphatics DO NOT drain from the face/head into the breasts.
• What you are seeing on these thermograms are coincidental vein patterns.
• Coincidence does not mean correlation, and correlation does not imply causation.

Lymphatic vessels begin in the tissues as a drainage system for fluid around the cells. All of these vessels travel up from the body below and down from the head above. 90% of these vessels drain into the left thoracic duct, while the remaining 10% drain into the right lymphatic duct. Lymphatics do not drain into the breasts. The lymphatics are a closed system with its own vessels just like the circulatory system. 

Another unique aspect of the lymphatic system is that it is completely unlike the circulatory system carrying blood. The pumping heart draws venous blood into it from the body while pushing arterial blood out to the body. The circulating blood is heated as it travels through the body core. Keep in mind that thermography can only “see” heat sources that are no deeper than 5mm from the skin surface. Since the lymphatics are only a drainage system, when it comes to the surface of the body the lymphatic vessels are simply draining the skin and heading deeper into the body. As such, thermography cannot see lymphatic vessels due to the fact that the fluid in the vessels is the same temperature as the surrounding tissue. 

The lymphatic system also has no pump. As such, the flow of lymph (the fluid in the lymphatic vessels) is extremely slow in comparison to the heated blood circulating through the heart. This last aspect, the flow rate of lymph, is another reason that these vessels are incredibly rare to see on a thermogram.

• In order to see a vessel on a thermogram it must be hotter that the background temperature of the tissues (e.g. skin).
• The Zeroth Law of Thermodynamics basically states that when two objects of differing temperature come in contact with each other they will eventually become the same temperature (they reach equilibrium).
• Since the lymph is coming from the surrounding tissues, the temperature of the lymph is the same as the surrounding tissue. 
• The flow rate of lymph through the lymphatics is so slow that the temperature of the fluid remains the same as the surrounding tissue.
• These factors make the lymphatic vessels invisible on thermography. 
• Circulating blood is heated as it moves through the body core.
• The blood flow rate through arteries and veins is fast. As such, the heated blood moving through the vessels doesn’t have enough contact time with the surrounding tissues to reach equilibrium.
• What we see on a thermogram is the reflection of the blood flow through the skin (i.e. veins and arteries).

What about the root canal infection itself? The human body has evolved to do all it can to survive. The mouth is one of the dirtiest places in the body. Chewing causes tremendous pressures on the teeth and jaws. Due to the importance of having to eat, the mouth is one of the fastest healing areas in the body. Now, let’s introduce an infection. In an effort to survive, what should the body do? Should it wall the infection off isolating it to the tooth area, or should it allow the infection to become deadly by moving to other areas of the body? It does exactly what you just thought, it walls the infection off to fight it and protect the rest of the body. The infection doesn’t pick some specific blood vessel to travel to some specific organ. 

Now you might be saying to yourself, “Ok so you can’t see lymphatics. What about the concerns with some people getting heart infections from dental procedures?”. These infections come about from bacteria being dislodged, falling into the venous system, and draining from the mouth – there is no direct connection from the lymphatics to the heart. If the patient has a heart condition that may be susceptible to infection (e.g. valve replacement), the bacteria may cause an infection. Keep in mind that bacteria are part of our normal environment both outside and inside our bodies. As such, and if knowing that no recent dental procedures have occurred, an infection of the heart can be coming from anywhere in the body through the venous system.

What about patients with lymphedema? First, there is no vascular pattern (thermal image) that can tell if a patient has lymphedema vs. some other neurovascular condition. As such, for a thermal image to correlate with this diagnosis the interpreting thermologist would need to already know that the patient has this condition (i.e. swollen limb). The accumulation of lymph causes swelling, which is seen on a thermogram as cold – not hot. Again, without the thermologist already knowing the diagnosis this cold image could also be caused by another pathology.

We have also seen statements from dentists and other thermography websites claiming that the teeth are connected to the breast acupuncture meridians. Please feel free to look up any acupuncture meridian chart. There is no such thing as a breast meridian. There are meridians that run through the breast, but there are no breast meridians. Perhaps some are trying to say that the stomach meridian runs directly from the mouth down to the breasts. However, the stomach meridian ends in the feet and not the breast. There is no direct connection.

It is so unfortunate that this topic needs to be addressed, but many patients are being needlessly scared and wasting thousands of dollars on unnecessary dental procedures and added thermograms. There is just no anatomic or physiologic evidence for this topic. A thermogram showing hot stripes from the face to the breast is simply coincidence. A broken clock is right twice a day. Coincidence does not mean correlation, and correlation does not imply causation.

As mentioned above, there are no thermal patterns or markers of any type that would allow for an interpretation of lymphatic congestion. It doesn’t matter if the image is of the breast, axilla (under arm area), or some other area of the body.

In breast cancer patients who have undergone the removal of a significant number of axillary (under arm) lymph nodes, and have obvious visual proof of lymphedema in the upper extremity, the resulting thermogram of the affected arm would then be a result of lymphatic congestion. However, without knowing the history of this patient, and visually confirming the condition, the interpretation of the upper extremity thermogram would be indistinguishable between some other form of circulatory and/or neurological abnormality.

Interpretations of thermal findings indicating cysts and fibrocysts shows a lack of the basic understandings of thermodynamics. Not to mention the research showing that we can only detect heat sources to a depth of 5mm from the surface of the skin. 

You will notice on these types of reports that the interpreter routinely calls attention to “cold areas” or “cold spots” as the location of cysts and/or fibrocysts in the breast. Since cysts are fluid filled sacs, one might think that this area under the skin would create a cold area at the surface. However, simple thermal conduction will not allow for a temperature difference between the cyst and the surrounding tissue. Take for example that a balloon filled with cold water (acting as the cyst) is placed inside a larger balloon filled with warm water (acting as the breast). What will happen over time? Both of the balloons will reach equilibrium and become the same temperature (Zeroth Law of Thermodynamics). This is the same thing that happens with cysts and fibrocysts in the breast. As such, there are no thermal signs of cysts or fibrocysts in the breasts.

This is another example of an inadequate education in thermal imaging. In this instance the interpreting thermologist is looking at a view of the side of the neck and sees a hot stripe leading from the area near the rear of the jaw down toward the front of the neck. This hot stripe is thought to be heat from an inflamed carotid artery. 

We have three very elementary errors here. The first is basic anatomy. We have seen websites that state that since the carotid artery is so close to the surface of the skin that it is easily evaluated using infrared imaging. We won’t bore you with an anatomy lesson numerating the layers of muscle, fascia, and other blood vessels that cover and protect this vital structure that conveys blood to the brain. Suffice it to say that the carotid artery is safely located deep in the neck close to the cervical spine. Remember that we cannot see anything deeper than 5mm from the surface of the skin. Secondly, if this heat stripe is a blood vessel how can one prove that it is inflamed only from the thermal image? Simply changing the volume of blood flow will change the size of the vessel; and thus, the appearance of increased heat. And lastly, true carotid inflammation (carotid vasculitis) carries with it a very specific set of symptoms.

So what is this heat stripe? It is the external jugular vein. One of the technical advantages inherent in performing thermography is that a live image is generated. As such, the technician or doctor can approach the patient and investigate the surface of the body for any interesting finding that appears on the live computer image. When seeing this hot stripe, the technician could use a pen to point at an obvious bluish line on the neck (external jugular vein) while looking at the infrared image. The results are obvious.

First, this has nothing to do with the type of camera used. Any office with a reasonable mount for the camera can leave the patient behind a wall or drape and provide imaging without the technician seeing the patient. However, this is not allowed in infrared imaging.

We all understand that we would prefer not to be undressed in front of a technician or doctor. But all of us also understand that when entering any health care facility the likelihood of having to disrobe is fairly high. As mature adults we understand that this can cause some anxiety, but disrobing in front of a technician or doctor of the same gender is something that is fairly common.

The real problem here is that providing imaging without the technician visually seeing the patient is against the standards and guidelines in thermography. It would be irresponsible of the technician not to observe the surface of the body being imaged. During the acclimation process the technician needs to properly position the patient to be sure that thermal artifacts will not be introduced into the images. Once the acclimation time has passed, the technician must re-enter the room to verify that the patient has not changed this position. This is part of the verification of proof of proper acclimation.

When performing breast imaging the technician has special responsibilities that would also preclude “privacy imaging’. Certain changes to the surface of the breast may occur due to surgeries or when a cancerous growth is present. It is the technician’s responsibility to visualize the surface of the breast in order to inform the interpreting thermologist if anything other than smooth uniformly colored skin is present. Surface changes can be critical in the thermal grading of the breast and the proper management of the follow-up recommendations.

With imaging the rest of the body the technician must also be observant for surface evidence of surgical sites (e.g. scars). At times, patients can forget these things when filling out their intake forms. Depending on the extent of certain surgical procedures, the thermal pattern in these regions of the body can be significantly altered. Without having a technician present to observe the surface of the body the interpretation of the thermogram may be in error due to the interpretation of a surgical artifact as a pathology.

It has also been said that many of these things can be overcome by having the patient acclimate in front of the camera in a “privacy imaging” setting. However, one cannot “see” these things in infrared, it’s just not possible. Even if a particular camera was able to provide additional visual imaging just like a regular video camera, you would have to let the patient know that you were looking at them just as if you were in the room. At this point you would be violating the entire “privacy imaging” idea. Decades of experience in thermography has shown that patients do not like having an infrared camera, much less a regular video camera, pointed at them during the acclimation time. It creeps them out.

“Privacy imaging” introduces the possibility of significant errors and violates the standards and guidelines in thermography.

Absolutely not! The argument for this practice seems to be that there is no way to know on your first thermogram whether or not your body was changing at the time. We have another question, if the follow-up 3 month thermogram showed that there was change, which image set would be the stable baseline? Would it be the first set or the 3 month later set? It sounds like you would need to do another set of images in another 3 months as a tie breaker. But what if this set also showed change? The bottom line here is that if you did need to return to do any of this the technology must be useless.

What would you think if your doctor took your temperature, noted it as a fever, and then told you to return the next day to see if this first reading was right? Reading core temperature is no different than a surface recording taken under proper thermal imaging guidelines. Either the information taken on the first thermogram is valuable or the technology is unstable and useless due to some variable in the patient’s physiology. Research following the same patients over a 5 year span has proven that the thermal patterns and differential temperatures at the surface of the body are remarkably stable and held within a very narrow range. These research studies were used to establish the normative database to which patients are compared when reading thermograms. Thermovascular patterns are as unique as a fingerprint and can be followed with accuracy for decades. It is when there is a change to this stable thermal fingerprint that a problem is signaled.

This begs the question as to why patients are being asked to return in 3 months. We recommend asking one of these offices for at least one peer-reviewed and published research paper demonstrating the need for this in order to establish a stable baseline. The research has already been done. In the early days of thermography each set of thermal images were taken in triplicate. The patient was acclimated in a temperature controlled imaging room under standard protocols for 15 minutes and then imaged. The patient would then be left for another 15 minutes and imaged again. This was finally repeated once more. In these early days thermologists were unsure about the stability of the process and the possibility of changes. Once the stability of the thermal data was established this practice was stopped. Then, as mentioned above, this was taken a step further by watching the thermal stability of patients for over 5 years. Studies have proven that a single set of thermal images taken under proper guidelines is completely accurate for analysis.

Under the established standards and guidelines for thermography, recalling patients for follow-up thermograms is based solely on clinical need. When it comes to breast thermography, follow-up thermograms are performed based on the known metabolism of breast cancers. Under these guidelines each breast must be graded into one of 5 thermobiological (TH) categories. The level of TH grading acts as an individualized risk assessment based on the patient’s own biology. Depending on the TH grading, and taking into consideration the metabolism of breast cancers, the patient will be asked to return in a reasonable amount of time.

Since it was established decades ago that a single thermogram is all that is needed for immediate analysis, why are some offices having all their initial thermogram patients return in 3 months?