While 'fever detectors' or 'fever cameras' are now hotly marketed, FLIR has gone the other way. While FLIR never called these devices by those terms, they have become even more conservative, rejecting even 'EBT', now calling them 'EST'.
In this note, we examine:
The various marketing terms for this thermal technology
Why FLIR switched from EBT to EST
What the difference between body temperature and skin temperature is
What the difference between forehand and inner canthus measurements are
The relationship between EST, EBT, fever, and coronavirus
****** ************ ** ******* *****other **** *** ****** ******** ******** ** *** ***** ****** ** **********, and may be complicated by perspiration, facial skin flushed from exertion, etc. The current evidence indicates that the region medially adjacent to the inner canthi is the preferred site for fever screening due to the stability of that measurement site. This is because this region is directly over the internal carotid artery. [emphasis added]
I think this is a good distinction to make between both acronyms. I suppose claiming EST over EBT would alleviate potential liability not to mention more clearly defines what is being detected. Props to FLIR for that.
it is important to note the difference in capabilities for each type of device. Since the Flir solution does not have a blackbody to partner with the thermal camera, then EST is more appropriate.
Forgive me if this question sounds ignorant but how does blackbody make it more appropriate to call it EBT versus EST? Are they not both measuring the surface temperature of a body?
Since the Flir solution does not have a blackbody to partner with the thermal camera
Thanks for raising this point. FLIR provided a response saying that they do support a blackbody but generally do not recommend it, their response below:
Yes, you can use FLIR thermal cameras with black bodies (BB) as part of an elevated skin temperature system setup. In fact, many of our integrators and partners are doing just that, taking our technology and then developing their own software solution that uses a BB as the reference. One example is Viper Imaging (Elevated Body Temperature Detection ).
Our handheld cameras that include our screening mode do not require a BB. Our new A4xx/A7xx Smart Cameras with EST configuration also have on camera screening mode, and in that configuration, do not require a BB either. But the A4xx/A7xx Smart cameras do support the use of a BB reference if users want to use that method. To do so, you simply turn on the BB reference in the camera control interface and place the cursor on the BB reference. Then your screening measurement tool will use that reference.
There are some tradeoffs with either EST system configuration. We believe our screening mode has some distinct advantages, two of which we’ve listed (below), but for those that wish to use a BB, we support that configuration as well:
Accurate to +/-0.5C, which meets the FDA and ISO spec
Compensates for variations in body temperatures throughout the day, by using the last ten persons screened as the reference
Does not require another piece of hardware to maintain and calibrate in the system.
Tamas, which system is that? Dahua I assume since that is what you sell.
You cannot even attempt to use Dahua to measure the inner canthus unless, as your demo shows, you stop and take your glasses off. However, Dahua is not recommending stopping and taking your glasses off, correct?
Yes, It is Dahua solution. Does not necessary stop. The glass is the confounding factor like to any brand. See for example flir demostrat video.
But If it can't find the hottest point (canthus) because the target wear the glass, it can be find the other hottest point on the face. And Dahua camera can find the faces! Therefore, it is suitable for measuring the elevated skin temperature of several people at the same time. :)
A bad approach is to think that the camera is looking for the canthus and starting the measurement there. The hottest point on the face is the canthus and the cameras messureing the hottest point what can it find on the face. See the video.
temperature values represent raw data? Or are they manipulated with some sort of "AI"?
Shay, good question. From what we have found so far, it depends on the system. FLIR is typically giving raw temperature data which can be argued as being good (non-manipulative) or bad (no AI).
What the "AI" is in a given system is a big question. How much AI and how accurate is that AI?
This is theoretically a straight forward application. Pick a spot, measure the temperature.
The only real value you would get from AI would be to do some kind of automated eye detector to measure the right area. But you are not going to do anything useful with AI to magically turn "bad" data into "good" data.
I think that some of the companies attaching the AI descriptor to these products are doing so to try and make it look like more than it is (which is a mostly useless way to try and flag infected people in a non-disruptive fashion).
The only real value you would get from AI would be to do some kind of automated eye detector to measure the right area.
speaking purely theoretically, i would think there might be considerable value in A.I., not necessarily in the improved spot measurement of EST, but rather in the holy grail of fever detection itself.
consider that a person's overall thermographic image contains a wealth of information, possibly with undiscovered correlations that could be trained to suggest possible positives.
consider that a person's overall thermographic image contains a wealth of information
What makes you think this?
If you think about the parts of the body that are typically available for observation by a camera you primarily have the hands and the head/face/neck.
Hands are going to be pretty useless for fever detection, IMO. They are extremities, and one of the areas of the body where circulation (and thus temperature indication) can vary significantly.
The head/face/neck is not much of a great indicator of internal core temp either, as research on this topic shows.
The rest of the body is going to be clothed (hopefully ;) ), so all you are going to read is the surface temperature of the clothing, which would vary dramatically based on the season and clothing in general. But in all cases, the clothing would obscure the actual underlying temperature in one way or another.
All of the data points you measure are only visible for a brief time. There might be more you could do if you had the option to measure skin temperatures over a longer period of time to see rate-of-rise data, or heat increase decrease over time of one area relative to another. But when all you get is a quick snapshot with little other reference info, you can only go so far with that.
Further, the whole problem is often complicated by not knowing the environment the person was in leading up to them coming in view of the camera. Were they running or carrying something heavy that would cause a normal temperature rise? Were they in sunlight? Under an HVAC duct? Are they aware they were going to be walking past a temperature monitoring camera and therefore took some action to try to alter their temperature reading? (medication, cold compress, etc).
but i wouldn't dismiss it.
I would :) My personal position is that much of the hype and interest around this topic is coming from people not having enough understanding of the pros and cons of both thermal cameras and AI, and thinking there is some way to link the two together to reveal an indictor of data that simply does not exist. Many people want these systems to work, for whatever reason, that they focus on the "good" data points, and ignore the "bad" ones, leading them to a false sense of trust in the systems.
Hands are going to be pretty useless for fever detection, IMO. They are extremities, and one of the areas of the body where circulation (and thus temperature indication) can vary significantly. The head/face/neck is not much of a great indicator of internal core temp either, as research on this topic shows.
well if you knew how to interpret the relative multiple data points, you could just hard code it into the program.
for instance when you say
Further, the whole problem is often complicated by not knowing the environment the person was in leading up to them coming in view of the camera. Were they running or carrying something heavy that would cause a normal temperature rise? Were they in sunlight? Under an HVAC duct?
in an effort to dismiss A.I. because of these complications, you miss the point: it's because of these complications that A.I. could have value.
do you think that the way that various body temperatures rise at multiple points on the body from running around the block is the same as a core temp increase from a fever? might the extremities lag? i don't know.
but that's the type of learning A.I. is good at.
fwiw, and in case you missed my disclaimer, "speaking purely theoretically", i would agree that the most likely explanation for tacking on A.I. to these has nothing to do with machine learning.
do you think that the way that various body temperatures rise at multiple points on the body from running around the block is the same as a core temp increase from a fever? might the extremities lag? i don't know.
but that's the type of learning A.I. is good at.
Yes, but you are talking about an unsupervised learning process, which is going to be much more complex.
in an effort to dismiss A.I. because of these complications,
I am not dismissing it simply because of complications, I am dismissing it because you are suggesting using AI to overcome the fact that there does not appear to be any way to correlate skin temperatures on a relatively limited part of the body to a core temperature, or more specifically a fever.
AI is good at a lot of things, but in the end the still has to be an actual answer to your question in the data you are trying to distill. You cannot just apply AI to a plate of green beans and expect it to predict the weather.
The first thing that comes to my mind where AI could be applied, would be to adjust for ambient temperature.
Over time, the ambient temperature is likely to change (unless the air conditioning is very accurate), something that will affect the skin temperature. If an AI solution uses the black body as reference, and then also measures spots in the camera field of view, it could detect if the area (or if certain areas in the field of view, e.g. right side) becomes hotter or colder.
The AI-solution could then adjust the reported temperature values adjusted for the ambient temperature effect upon the skin temperature.
Of course, this wouldn't help much for different temperatures outside of the camera field of view, but it could provide a minor increase in reported temperature values.
Maybe. I'm not sure you'd really need AI to do a temperature offset. I think you'd really need to be aware of the ambient temperature of the area the person was in preceding the reading to model how it would have affected their skin temperature over the last several minutes leading up to the reading. You'd probably also need some way to estimate body fat, mass, and metabolism, as not all people will respond in the same way to an ambient temperature.
This all still ignores the fact that fevers are going to be pretty rare in general, and you are going to need to allow for a moderately high cutoff point before even flagged a temperature as "elevated", otherwise you are going to be stopping so many people that you might as well just keep the business closed or at massively reduced capacity.
FlIR supply Thermal lens modules to a lot of other camera manufacturers, so if FLIR are now backtracking on the viability of the application. Shouldn’t it lead to other manufacturers, who are using FLIR sensor technology, to also scale back their claims ????
The FLIR E40sc thermal imaging camera has an image resolution of 160 x 120 pixels, resulting in 19,200 temperature readings at a glance. very good result by flir.
How about witchcraft? The terminology itself is accurate, but I think that in most cases the sale itself screams opportunism, the application wreaks of snake oil, and the accuracy will subject unknown numbers of people to unfounded paranoia-driven ‘stop and frisk’ assessments and interdiction responses. Just one man’s opinion.
Just a thought from someone not as versed as some here on thermal.
Doesn't the distance of the subject being scanned from the camera in relation to the resolution of the camera being used play a factor as the camera needs to be able to be able to have a certain amount of "pixels" in an area in order to obtain a reliable temperature reading?
I ask because some of the solutions we have seen show people fairly far away from the camera. Given the fact the canthus of the eye is about 1/4" square, there has to be a point on where the sensor can no longer get an accurate reading and I am not sure how much can an algorithm or AI do to make something the sensor cannot physically see appear, as Brian Karas pointed out earlier.
First off, I applaud FLIR’s honesty at what their cameras can and can’t do and their willingness to risk sales for the sake of integrity. From the responses to this article alone, it appears not many other manufacturers are willing to do this.
With that said, when the lock downs started and I began hearing about companies wanting ‘fever-detecting’ cameras, my first thought was that it reminded me of the initial post-911 response where every high-rise building needed to install huge cement planters in front of their doors in order to stop terrorists. Within a relatively short timeframe, most realized that these large planters were relatively ineffective in stopping anything other than a vehicle wanting to drive through their lobby and the fad started to fade.
Now, I’m reading these articles and hearing from politicians such as California’s Governor who are saying things like requiring all business to check temperatures of anyone (employee or patron) before they enter, and I’m reminded of the outcry from the public after the Las Vegas shootings on how if only that hotel would have had metal detectors in place before allowing entry into the elevator then the whole massacre could have been avoided. For a short time, there was actually talk of legislative action requiring all hotels to have metal detectors in place. Sure, it would have stopped this incident, but it would also have stopped all hotel usage by everyone as nobody would willingly allow their luggage to be opened and searched for any metal before they went to their room.
I firmly agree with the previous article that showed the incredible spike in interest to be followed by just as rapid a drop in interest, and I hope the companies that are spending their millions in R&D are not jeopardizing themselves when society quickly forgets about the pandemic and refuses to allow their temperature to be taken as a precursor to normal life. As one of my customers pointed out, their intent is that if they purchase any of these cameras, they fully expect to donate them to other organizations in the very near future.
ok, tons of data on this post. All without true testing of the capability in a controlled manner.
I wanted to remind everyone that hospitals, schools, and medical facilities all use thermometers that work on very old technology..... Why? because they provide a baseline of information that is used to determine possible illnesses.
Purpose. A thermometer is used in health care to measure and monitor body temperature. In an office, hospital or other health care facility, it allows a caregiver to record a baseline temperature when a patient is admitted. Repeated measurements of temperature are useful to detect deviations from normal levels.
A thermometer measures temperature through a glass tube sealed with mercury that expands or contracts as the temperature rises or falls. ... As temperatures rise, the mercury-filled bulb expands into the capillary tube. Its rate of expansion is calibrated on the glass scale.
Thoughts to ponder: It this measurement accurate? Would adding AI to this old technology for tracking and trending provide any better measurement? Can it be helpful to track a person overtime against their own body temp from day to day to identify a pattern?
How do contactless thermometers work now? Are noncontact infrared thermometers accurate?
The sensitivity and specificity for the non-contact thermometer is 97%. ... The non-contact infrared thermometer is a reliable, comfortable and accurate option for measurement of temperature and is very useful for the screening of fever. All matter emits energy in the form of IR (heat). ... IR light works like visible light—it can be focused, reflected or absorbed. Handheld IR thermometers typically use a lens to focus light from one object onto a detector, called a thermopile. The thermopile absorbs the IR radiation and turns it into heat.
Forehead thermometers, which typically cost about $30 to $50, use an infrared sensor to measure the heat from the forehead. ... Some studies have found forehead thermometers highly accurate, while others found them not as reliable as rectal thermometers—considered the gold standard by many physicians.
The point of this long post is that technology is constantly changing and the only way to determine if a new technology is something that can be used for screening is to TEST IT in a controlled study.
So this is not a question of what it should be called, at least in the US. I understand this would be interesting from a marketing perspective. However, in the US, the FDA has jurisdiction over these applications. And yes, I am aware that the FDA has just released a temporary guideline to relax the 510k ruling. However, it is a "non-binding" guideline and it is temporary. In other words, the FDA may decide at their sole discretion when and how to enforce this as well as when to remove this guideline. So nothing has really changed, other than the FDA allowing companies to install cameras temporarily without going after the vendor/distributor/reseller or integrator for now, due to the high demand in this crisis. This may me revoked at any time.
Which brings me to why FLIR has changed the EBT to EST. If you read the FDA 510K notification for the FLIR cameras, you'll see a section called "Intended Use". That is the official claim for which these cameras received the 510k in the first place. Any claim being made that goes beyond this claim is outside of the scope of the 510k and would therefore be a violation of the 510k. The intended use for the camera states: "...intended for us as an adjunct to other clinical diagnostic procedures in the diagnosis, quantifying, and screening of differences in skin surface temperature changes. It can visualize, document temperature patterns and changes."
In fact, no thermal camera has ever been cleared by the FDA for body temperature measurements of any kind. This wouldn't be possible, since a thermal camera can only measure the infrared radiation emitted by the surface of a solid object (or skin). There are challenges with correlating skin temperature with the inner core body temperature, due to many physiological effects, such as sweating, fat cells, thermoregulation etc.
The inner canthi/tear duct area is the most closely correlated region the body temperature in the face. Hence the recommendation to measure temperature there.
So, calling it an "Elevated Body Temperature" measurement has the word body temperature in it, which could technically be looked at as a claim that is outside of the approved intended use for the 510k.
This is not FLIR specific and is true for any thermal camera or optical temperature measurement for that matter in the US. Measuring skin surface temperature is not equal to sticking an oral thermometer into somebody's mouth. This would be a measurement by conduction.
Even an oral or rectal fever measurement differs from the inner core temperature, albeit much less than a thermal camera does when measuring skin surface temperature.
Forgive a stupid question, but regarding this statement from article: "Some people who have elevated skin temperature (EST) may have elevated body temperature (EBT). Some of those people with EBT may have a fever. Some of those people with a fever may have coronavirus". Can someone tell me if someone with a fever necessarily has EBT, and if EBT, will they necessarily have EST?
Can someone tell me if someone with a fever necessarily has EBT, and if EBT, will they necessarily have EST?
Good questions. We are not doctors but our understanding is that everyone with a fever (i.e. pyrexia), by definition, has elevated body temperature. However, people can have an elevated body temperature and not have a fever (e.g., overheating / hyperthermia).
Also, you can have an elevated body temperature but not elevated skin temperature. For example, if you have a fever but you throw cold water on your face, your skin temperature will temporarily fall. Or vice versa, you can have elevated skin temperature but not elevated body temperature (e.g., when standing in the sun, your skin temperature can exceed your body temperature, imagine standing in line going into a theme park).
Yes, thanks. I guess this was what I was trying to understand: "you can have an elevated body temperature but not elevated skin temperature". You and Brian have convinced me to be cautious about "fever detection", but I'm still trying to understand if this is at the level of snake oil or if there is some usefulness to this application. Will a fever most often be indicated by elevated skin temps (especially when you remove special circumstances such as throwing cold water on your face)? I don't know if I'm asking all the right questions, but am wondering if this technology will catch fevers enough of the time that it would still be useful as long as proper expectations are set for the customer.
but am wondering if this technology will catch fevers enough of the time that it would still be useful as long as proper expectations are set for the customer.
That strikes me as the best case honest scenario for sellers. There does not seem to be any reasonable way to use at a distance, on the move, 'fever' screening to reasonably guarantee to catch all fevers. The question then becomes how many people / what percentage of people with fevers still pass and are some systems relatively better at minimizing this?
And if you are a buyer and you say something like "Ok, still many people with fevers will be missed but I will catch 1 per [day, week, month, etc.]" does that justify the system's purchase and use?
I think this ignores the opposite case of false positives. How many people are going to be stopped from entering a place because the system says their forehead is too hot?
For an office, there might be minimal risk, people theoretically want to go to work (or have to go to work), and it's just kind of a hassle you deal with. But for consumer things like movies, or theme parks, I think these systems will become a discouragement to attendance.
For the office environments, people will learn to beat the system in short order if it actually becomes commonplace. Blast the A/C in your car at your face for a few minutes before going in. Use a cold-pack, take some ibuprofen, etc.
Maybe I'm oversimplifying, but instead of turning someone away due to a false positive, maybe after a positive you next provide a secondary test with a thermometer or another technique with greater accuracy? Not suggesting rectal thermometer here, but there must be something else semi quick and accurate. :-)
I think this ignores the opposite case of false positives. How many people are going to be stopped from entering a place because the system says their forehead is too hot?
For sure, I agree that the risk is either too many people with fevers missed or too many people without fevers being stopped (your case of false positives).
However, from what we have seen so far, false positives tend to be low. Our theory behind that is that the systems tend to include a fairly significant margin of error between 'normal' temperature and 'high' alerting level plus people tend to be detected 'low'. The combination means a greater risk for people with fevers being missed, in how these are being used. Make sense or?
Fever is defined as "an abnormally high body temperature". Any body temperature above the normal average of 98.6F is considered to be a fever, but medically it is generally not considered to be indicative of any kind of infection/virus/etc until it is above 100F.
Skin temperature may or may not directly correlate to body temperature. Your skin can act as a heat sink for your body, particularly along with perspiration. Your skin temperature may be higher, or lower, than your core body temperature for a variety of reasons.
It is important to note (IMO) that by definition body temperature cannot be accurately measured anywhere external (eg: skin/surface). This would be roughly equivalent to measuring the outside wall temperature of your house and saying "it is hot inside this house".
Good image. I was thinking more along the lines of measuring the outside surface of a house that has been exposed to sun and comparing that to the interior temperature.
Of course, if you measured the outside surface temp of that house, I would wager it is still much warmer inside.
FLIR posted training recently that has quite clear and constrained usage instructions:
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Comments (49)
Undisclosed Integrator #1
I think this is a good distinction to make between both acronyms. I suppose claiming EST over EBT would alleviate potential liability not to mention more clearly defines what is being detected. Props to FLIR for that.
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Undisclosed Integrator #2
it is important to note the difference in capabilities for each type of device. Since the Flir solution does not have a blackbody to partner with the thermal camera, then EST is more appropriate.
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Tamas Menyhart
I think the green "+" sign is the canthus, but I am not a medic.
You can calling the solution whatever you want, but it works good.
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Shay Fogel
Does anyone know if the temperature values represent raw data? Or are they manipulated with some sort of "AI"?
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Undisclosed Manufacturer #6
FlIR supply Thermal lens modules to a lot of other camera manufacturers, so if FLIR are now backtracking on the viability of the application. Shouldn’t it lead to other manufacturers, who are using FLIR sensor technology, to also scale back their claims ????
Or would that be asking to much from them ?
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Arindam Bhadra
The FLIR E40sc thermal imaging camera has an image resolution of 160 x 120 pixels, resulting in 19,200 temperature readings at a glance. very good result by flir.
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George Peffer
I voted corona virus detector. This way anyone with a brain would recognize the scam.
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Undisclosed Manufacturer #7
How about witchcraft? The terminology itself is accurate, but I think that in most cases the sale itself screams opportunism, the application wreaks of snake oil, and the accuracy will subject unknown numbers of people to unfounded paranoia-driven ‘stop and frisk’ assessments and interdiction responses. Just one man’s opinion.
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Undisclosed Integrator #8
Very good article to help sort through some terminology. Thank you.
The Mobotix unit does a great job at reading the inner canthi and our customer have had very good success with it.
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Undisclosed Integrator #10
Just a thought from someone not as versed as some here on thermal.
Doesn't the distance of the subject being scanned from the camera in relation to the resolution of the camera being used play a factor as the camera needs to be able to be able to have a certain amount of "pixels" in an area in order to obtain a reliable temperature reading?
I ask because some of the solutions we have seen show people fairly far away from the camera. Given the fact the canthus of the eye is about 1/4" square, there has to be a point on where the sensor can no longer get an accurate reading and I am not sure how much can an algorithm or AI do to make something the sensor cannot physically see appear, as Brian Karas pointed out earlier.
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Undisclosed Distributor #11
This is doing the rounds in the UK at the moment
I have had some people in china check it out and it appears to be genuine Dahua kit but with Chinese web interface only.
Very interesting prices for the local market only !
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Undisclosed Integrator #12
First off, I applaud FLIR’s honesty at what their cameras can and can’t do and their willingness to risk sales for the sake of integrity. From the responses to this article alone, it appears not many other manufacturers are willing to do this.
With that said, when the lock downs started and I began hearing about companies wanting ‘fever-detecting’ cameras, my first thought was that it reminded me of the initial post-911 response where every high-rise building needed to install huge cement planters in front of their doors in order to stop terrorists. Within a relatively short timeframe, most realized that these large planters were relatively ineffective in stopping anything other than a vehicle wanting to drive through their lobby and the fad started to fade.
Now, I’m reading these articles and hearing from politicians such as California’s Governor who are saying things like requiring all business to check temperatures of anyone (employee or patron) before they enter, and I’m reminded of the outcry from the public after the Las Vegas shootings on how if only that hotel would have had metal detectors in place before allowing entry into the elevator then the whole massacre could have been avoided. For a short time, there was actually talk of legislative action requiring all hotels to have metal detectors in place. Sure, it would have stopped this incident, but it would also have stopped all hotel usage by everyone as nobody would willingly allow their luggage to be opened and searched for any metal before they went to their room.
I firmly agree with the previous article that showed the incredible spike in interest to be followed by just as rapid a drop in interest, and I hope the companies that are spending their millions in R&D are not jeopardizing themselves when society quickly forgets about the pandemic and refuses to allow their temperature to be taken as a precursor to normal life. As one of my customers pointed out, their intent is that if they purchase any of these cameras, they fully expect to donate them to other organizations in the very near future.
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Undisclosed Integrator #2
ok, tons of data on this post. All without true testing of the capability in a controlled manner.
I wanted to remind everyone that hospitals, schools, and medical facilities all use thermometers that work on very old technology..... Why? because they provide a baseline of information that is used to determine possible illnesses.
Purpose. A thermometer is used in health care to measure and monitor body temperature. In an office, hospital or other health care facility, it allows a caregiver to record a baseline temperature when a patient is admitted. Repeated measurements of temperature are useful to detect deviations from normal levels.
A thermometer measures temperature through a glass tube sealed with mercury that expands or contracts as the temperature rises or falls. ... As temperatures rise, the mercury-filled bulb expands into the capillary tube. Its rate of expansion is calibrated on the glass scale.
Thoughts to ponder: It this measurement accurate? Would adding AI to this old technology for tracking and trending provide any better measurement? Can it be helpful to track a person overtime against their own body temp from day to day to identify a pattern?
How do contactless thermometers work now? Are noncontact infrared thermometers accurate?
The sensitivity and specificity for the non-contact thermometer is 97%. ... The non-contact infrared thermometer is a reliable, comfortable and accurate option for measurement of temperature and is very useful for the screening of fever. All matter emits energy in the form of IR (heat). ... IR light works like visible light—it can be focused, reflected or absorbed. Handheld IR thermometers typically use a lens to focus light from one object onto a detector, called a thermopile. The thermopile absorbs the IR radiation and turns it into heat.
Forehead thermometers, which typically cost about $30 to $50, use an infrared sensor to measure the heat from the forehead. ... Some studies have found forehead thermometers highly accurate, while others found them not as reliable as rectal thermometers—considered the gold standard by many physicians.
The point of this long post is that technology is constantly changing and the only way to determine if a new technology is something that can be used for screening is to TEST IT in a controlled study.
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Markus Tarin
So this is not a question of what it should be called, at least in the US. I understand this would be interesting from a marketing perspective. However, in the US, the FDA has jurisdiction over these applications. And yes, I am aware that the FDA has just released a temporary guideline to relax the 510k ruling. However, it is a "non-binding" guideline and it is temporary. In other words, the FDA may decide at their sole discretion when and how to enforce this as well as when to remove this guideline. So nothing has really changed, other than the FDA allowing companies to install cameras temporarily without going after the vendor/distributor/reseller or integrator for now, due to the high demand in this crisis. This may me revoked at any time.
Which brings me to why FLIR has changed the EBT to EST. If you read the FDA 510K notification for the FLIR cameras, you'll see a section called "Intended Use". That is the official claim for which these cameras received the 510k in the first place. Any claim being made that goes beyond this claim is outside of the scope of the 510k and would therefore be a violation of the 510k. The intended use for the camera states: "...intended for us as an adjunct to other clinical diagnostic procedures in the diagnosis, quantifying, and screening of differences in skin surface temperature changes. It can visualize, document temperature patterns and changes."
In fact, no thermal camera has ever been cleared by the FDA for body temperature measurements of any kind. This wouldn't be possible, since a thermal camera can only measure the infrared radiation emitted by the surface of a solid object (or skin). There are challenges with correlating skin temperature with the inner core body temperature, due to many physiological effects, such as sweating, fat cells, thermoregulation etc.
The inner canthi/tear duct area is the most closely correlated region the body temperature in the face. Hence the recommendation to measure temperature there.
So, calling it an "Elevated Body Temperature" measurement has the word body temperature in it, which could technically be looked at as a claim that is outside of the approved intended use for the 510k.
This is not FLIR specific and is true for any thermal camera or optical temperature measurement for that matter in the US. Measuring skin surface temperature is not equal to sticking an oral thermometer into somebody's mouth. This would be a measurement by conduction.
Even an oral or rectal fever measurement differs from the inner core temperature, albeit much less than a thermal camera does when measuring skin surface temperature.
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Undisclosed Integrator #13
Forgive a stupid question, but regarding this statement from article: "Some people who have elevated skin temperature (EST) may have elevated body temperature (EBT). Some of those people with EBT may have a fever. Some of those people with a fever may have coronavirus". Can someone tell me if someone with a fever necessarily has EBT, and if EBT, will they necessarily have EST?
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Undisclosed Integrator #13
Thanks Brian. This helps: by definition body temperature cannot be accurately measured anywhere external (eg: skin/surface)
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John Honovich
FLIR posted training recently that has quite clear and constrained usage instructions:
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