Infrared Device 

Fever of Unknown Origin (FUO) refers to the presence of a documented fever for a specified time, for which a cause has not been found after a basic evaluation. The ability to locate the fever source would add efficiency to the diagnostic process. This technology will be used to aid in the diagnosis and treatment of FUO. It could also help localize the source of any fever. This would be useful in emergency rooms and by ambulatory care physicians. In 2002, there were approximately 17 million visits to emergency rooms and ambulatory care physicians, where the primary reason for a visit was fever. As the product is developed, the goal would be a device that could be sold to ambulatory care physicians and then ultimately over the counter. 

The measurement of the temperature of the human body to aid in clinical diagnosis has remained mostly unchanged since the first glass thermometer in 1868. The temperature measurement is normally confined to one location, such as the mouth or under the arm. The measurement of a single location severely limits the amount of information that can be gathered when compared to the measurement of multiple locations on the body. By measuring multiple locations, it is possible to reconstruct the thermal image in three dimensions. This information can then be used to localize the origin of the increased temperature.  

The ability to locate the fever source would add efficiency to the diagnostic process. For instance, by determining that an ear infection and not the urinary tract is the fever source could save unnecessary medical tests. Also if the diagnosis is a viral disease, it could save unnecessary antibiotic use. The ability to detect occult bacteremia in children would be a big advantage. Finally, there is a subset of fevers where a source is never found, which is called FUO. This occurs at great expense and discomfort to the patient. 

Fever is defined in relationship to normal body temperature, which varies by person, time of day, age, and activity. The average normal body temperature is 98.6°F (37°C). The standard definition of fever is a rectal temperature of 100.4°F (38°C). Fever is not an illness; rather it is an important part of the body's defense against illness. 

Almost everyone has experienced a fever. According to the National Ambulatory Medical Care Survey: 2002 Summary, there were 12,258,000 doctor visits where fever was the principal reason for visit (1). There were 5,310,000 visits to emergency departments where fever was the principal reason for a visit. It was the third most common principal reason to visit an emergency department (2). 

Fever is a common complaint often seen in children at the emergency department. The number of children that visit an emergency department can vary from 15-30%. Fever is a common complaint in 50% of the patients (3). An occult life-threatening bacteremia occurs in approximately 1.6% to 3% of children presenting to an emergency department with fever and no obvious source (4). 

Fever is one of the most common presenting signs in the ambulatory care pediatric office. It is present 19% to 30% of the time (5). Approximately 3.1% to 7.4% of children have bacteremia, and if left untreated can result in meningitis or other serious sequelae. (6). 

In most cases, the cause of the fever is identified. However, in about 20% of children with a fever, no cause is found after a complete history and physical (7). A diagnosis of FUO is made if the fever persists longer than three weeks, the patient's temperature is greater than 101°F (38.3°C), and no diagnosis is made after one week of rigorous inhospital investigation.  Exact demographic and epidemiological statistics on FUO are difficult to determine due to the extraordinarily broad range of underlying causes affecting men and women of all ages (8). Also, the work up for FUO can be quite extensive and expensive. 

Further areas of interest are listed below:

  1. Evaluating fevers of unknown origin (FUO) major problem in the ER.
  2. Vascular claudication issues
  3. Broken bone evaluation prior to x-ray
  4. Diabetic neuropathies
  5. AV fistula evaluations
  6. Incubator temperature spread evaluations of newborns
  7. Possible organ transplant temperature checks
  8. Dermatology surface tumor evaluation
  9. Prostate tumors
  10. Depth of anesthesia and perfusion
  11. Tumor evaluation

Any of the above represents significant opportunities for this modality and will be the ultimate focus of the company's growth.

Theory of Operation

The ancient Egyptians moved their hands across the surface of the body to scan and monitor changes in the body. The Greek Physician Hippocrates wrote in 400 B.C.," In what ever part of the body excess of heat or cold is felt; the disease is there to be discovered."  A device that would be able to measure the temperature gradient of the human body would be useful in locating the source of the fever. The theory is that the site of the fever through the production of an inflammatory response will produce a localized increase in temperature that can be detected. Human skin is a very efficient emitter of infrared energy, which means that the intensity of infrared energy occurs in direct proportion to skin temperature. The metabolic activities of underlying tissues will also affect skin temperature.

Technology

The technology is based on AGC's proprietary approach to the three dimensional analysis of thermograms to detect fever location. There are numerous diagnostic imaging modalities including x-rays, computed tomography, positron emission tomography, ultrasound, magnetic resonance imaging, and thermography. These imaging modalities have been useful, but nevertheless are complicated by needing to know the body's complex anatomical relationships. Pathological processes often have multiple anatomical and functional changes. Two dimensional image representations do not completely meet the needs of the physician. Three dimensional imaging is one advance that has enabled doctors to be more efficient in their diagnosis. Three dimensional computed tomography and magnetic resonance imaging are popular current examples. 

Thermal imaging has the potential for simple, effective, noninvasive mass screening of patients. Thermal images are related to body surface temperature distribution and appear quite different from optical images. While physicians have vast experience in interpreting visual images, thermal image analysis would be greatly improved if a means would be provided to relate the thermal images to their corresponding optical and anatomical source. 

Not only is the technological advance related to the three dimensional analysis but also to the type of thermal imaging system used. A patent will be filed to protect against market penetration. More information will be provided once a patent is filed. 

Current Competitive Products

There are several thermal imaging systems currently approved by the FDA. Since 1990, there have been eleven device approvals. The device classification is Class I, general controls. They have various indications for use including aiding in the diagnosis of breast cancer. None of the approved devices are indicated for use in fever localization. The companies are Infrared Sciences Corp., Titronics Research & Development Co., Thermatrek, Micro Health Systems, Inc., IX-DR, Inc., Dorex, Inc., Telesis Technologies Incorporated, Meditherm, Inc., Sie-Med, Inc. (Germany) and Magnetec Enterprises (US), Omnicorder Technologies, Inc. and Inframetrics, Inc. 

None of these products are currently being used in the indications proposed by our Company. Our advantage will be our technology and patent strategy specific to circumvent the current competitors and also create barriers to any further portfolio development by them. 

References

  1. Woodwell DA, Cherry DK. National Ambulatory Medical Care Survey:  2002 Summary. Adv Data Aug 2004;346.
  2. McCaig LF, Burt CW. National Hospital Ambulatory Medical Care Survey:  2002 Emergency Department Summary. Adv Data Mar 2004; 340.
  3. Graneto J. Pediatrics, Fever. eMedic Jun 2004.
  4. Finkelstein JA, Christiansen CL, Platt R. Fever in Pediatric Primary Care:  Occurrence, Management, and Outcomes. Pediatr Jan 2000; 105:260-266.
  5. Eskerund JR, Laerum E, Fagerthum H, Lunde PKM, Naess AA. Fever in general practice:  I. Frequency and diagnosis. Fam Pract 1992; 263-269.
  6. Dershewitz RA, Wigder HN, Wigder CM, Nadelman DH. A comparative study of the prevalence, outcome, and prediction of bacteremia in children. J Pediatr Sep 1983; 103(3):352-8.
  7. Sadovsky R. Managing Fever Without Source in Infants and Children. Amer Fam Phys June 2001:1.
  8. Holt DA, OHaight DO. Fever of Unknown Origin. Best Pract of Med May 2000.