Washington helping people resume normal life.
The thermal cameras և “temperature tablets” booths have been announced as the first possible line of defense against new outbreaks. But in a new scan by IPVM, researchers warn that the tools are dangerously ineffective, increasing the risk that infected people could penetrate medical checkpoints and continue to spread the virus unattended.
Immediately after discussing the results of the Food and Drug Administration’s investigation with The Washington Post on Thursday night, the agency issued a warning that improper use of the devices could lead to inaccurate measurements “posing potentially serious risks to public health.”
The agency also said it was sending official “warning letters” to one of the companies in question, as well as to three other companies, for selling “unapproved, unexplained, unauthorized thermal imaging systems.”
In a letter to Certify Global, FDA officials said the use of the devices posed a risk of misdiagnosis, especially if they were used to scan multiple people at the same time, so that a person with an undiagnosed fever could “prevent becoming less infected.” control guidelines. “
Researchers have found that seven widely used scanners try to compensate for the inaccuracies of low-cost sensors և unpredictable factors in real tests by “normalizing” people’s temperature readings.
But they claim that this “compensatory algorithm” is seriously damaging the medical utility of the devices. Their research found that a feverish person with a nuclear temperature of 100.4 degrees Celsius can be rated as 98 degrees Celsius, which is in the healthy range.
“The utility of these devices as cleaning agents is now highly questionable, and they certainly pose a threat to public health as they actively report tenders as normal,” said Conor Hill, lead researcher in the journal Biomedical Optics.
Representatives of tested, Certified, Dahua, Meridian և ZKTeco companies dispute the results, saying that their systems do not manipulate the temperature, but in some cases use software techniques to “self-regulate” their environment.
“The deviation parameter is not intended to ‘distort’ the results. “It is designed so that customers can receive alerts only when there are real threats,” said Larry Reed, CEO of ZKTeco, which makes the SpeedFace thermal imaging system, which sells for about $ 3,800. “A hot summer day in Arizona, [non-feverish] “Employees can turn on the device alarm all day if it is set to 101 degrees. և Employees examine it as soon as they enter the building.”
Peter Plasman, a logistics expert whose British company Thermetrix designs thermal imaging systems for medical use, says the study shows how companies have tried to boost their business by simplifying how well the devices work.
“It is mainly the problem with infrared imaging. “It is so deceptively easy,” he said. “You point the camera at someone, you get a beautiful colorful picture, you get a temperature reading. Great But it’s all rubbish. There are so many factors to consider. ”
The companies have developed thermal imaging systems with the ability to measure temperature faster, at a safer distance, than traditional infrared thermometers, which measure temperature from a person’s forehead, ear or mouth.
Scanners use infrared sensors to analyze the heat radiating from human skin, a close but incomplete reflection of the body’s core temperature. Եւ Some systems are advertised in such a way as to be able to assess many people in the transient crowd.
The FDA typically requires that thermal scanners այլ other medical devices be tested for safety և efficiency in a 510 (k) cleaning process. However, in April the agency said it would no longer require pre-market reviews or objections to non-manufactured devices that “do not pose an unnecessary risk.”
A new wave of thermal scanners has emerged, say researchers who count more than 200 companies that now manufacture or advertise such devices. Many companies first entered the market last year without any previous thermal imaging or medical device experience.
The FDA has said the change is needed to address fears of a shortage of devices. But researchers say they are concerned that such unverified systems are now widespread across the country and could fuel a “false sense of security” that could endanger public health.
Cerm scanners face a huge shortcoming in their ability to detect coronavirus infections. About 40% of infected people will have no fever at all, according to the Centers for Disease Control and Prevention last year. And a person’s temperature can change dramatically based on a number of factors, including whether they are overweight, stressed, menopausal, or wearing heavy clothing, or if they have recently exercised, gotten out of a hot car, or drank alcohol or caffeine.
But since there is no immediate alternative to detection, many officials consider heat screening to be the only way to detect someone who may trigger a new outbreak. Some businesses – local governments – have spent tens of thousands of dollars on a single camera to strengthen their defenses.
The FDA has worked to clarify Americans’ expectations of how useful the systems may be. The agency says in official instructions that the heat scanner “will not effectively determine if anyone finally has COVID-19.” that they “have not been proven to be accurate when used to raise the temperature of several people at the same time”; that their accuracy largely depends on “careful adjustment: operation”. «that” their effectiveness as part of efforts to reduce the spread of the disease is mixed. “
Bill Meisel, chief medical officer at FDA’s Office of Radiation Health Devices Assessment Office, said the study found a number of systems that “did not have the level of accuracy we expected.” Even after a change in the premier market last year, he said the FDA still requires all devices to meet certain performance expectations. The agency, he added, regularly monitors problematic systems and works with companies to correct errors when it turns out that their products are underperforming.
According to him, the devices should play only a limited role in assessing the risks during the epidemic; they can not replace social distance, masking or more traditional medical examination.
He said the thermal imaging devices were “imperfect, they are especially imperfect when examined by COVID”. “The inaccuracy of devices is one of the aspects that contributes to imperfection.”
IPVM researchers have not tested traditional thermometers, and their results have shown that some FDA-cleaned devices have returned to almost perfect accuracy. But all the heat scanners they tested seemed to deliberately “normalize” high temperatures in a healthier, non-fever-like area. The colder readings were raised higher, and the warmer readings lower.
The tested systems relied on low cost with sharply low accuracy. Several scanners used a sensor with a resolution of about 1,000 pixels, which is much more limited than the 76,000-pixel sensor found in one of the FDA-tested cars used as a controller. device:
To obtain an accurate temperature reading, the International Medical Electrical Equipment Guidelines state that systems should only be used in a controlled environment with regularly calibrated devices that are always “ready”. For example, people entering a closed waiting room will offer very different results than others who have been queuing up.
But companies, according to Haley, seem to have taken on that challenge, as systems seem to be constantly working across a wide range of ever-changing conditions.
The systems, says Hale, were designed to “maintain the appearance of normal function despite poor device performance or inspection conditions, allowing manufacturers to cover performance issues while selling much wider use cases.”
IPVM is a surveillance research team that studies camera hardware, imaging equipment and other technical tools for its members, mainly in the field of security. Its researchers studied the systems in a Pennsylvania temperature-controlled storage laboratory.
The companies tested are not household names, but they form the technical backbone of screening systems used in schools, retail stores and workplaces in the country. The price of the devices ranges from $ 600 to $ 13,000,: it is promoted that they are able to scan the entrance of an individual or massively evaluate visitors.
The Maryland-based Certificate of Appliance Found in Casinos and Hotel Dealers advertises on its website that it offers the “# 1 Heat Detection և Heat Scanning” solution on the market «could” replace hand-scanning “.
Certification spokeswoman Asmin Nysser said the system does not change the high temperature, but sets a minimum temperature level that will return a reading of 96 degrees if the scan fails. The system, he said, “uses world-class sensors for thermal application, which are accurately tested for accuracy.”
In a statement to LinkedIn, Vice President Tim Goodwin said that devices like the SnapXT Pro, with its $ 2,000 thermal scanner with eight-inch touchscreen, can be found in “more than 75% of NFL stadiums.” An NFL spokesman disputed that claim, saying the devices were used in about a dozen of the league’s 30 stadiums. (Nysser said the comment refers to the number of open stadiums when the post was written last year, that at that time Certified devices were located in five of the eight stadiums and then open to visitors).
Plasman says that the medical industry standard for deploying such systems, which includes everything from examination room lighting to humidity to the time when people should air condition before testing, is often overlooked in the real world, where unpredictable conditions can occur. social circumstances. They differ wildly; the results are distorted.
He said he had seen a flow of companies offering brilliant marketing materials but with little commitment to best practices in public health, adding that he was concerned that their widespread distribution could hamper efforts to avoid new outbreaks.
“It has to be done right,” he said, “or it can do more harm than good.”