*G.V. Pramod, **M S Shrinidhi
*Reader Department of Oral Medicine and Radiology, Bapuji Dental College and Hospital Davangere - 577 004, Karnataka
**Professor and Head, Department of Periodontics Sharavathi Dental College and Hospital Shivamogga
Thermal Thermal Estimated Estimated Major Major
device sensitivity cost ($) date of advantages disadvantages
(0C) inception
Direct Contact Methods 1. Hand
2. Mercury 2 – 3 0 100’s B.C. - Convenient - Subjective
thermometer 0.1 – 0.2 2 1500’s - Inexpensive, - Requires
convenient contact
3. Thermistor, thermocouple 0.01 – 0.02 2000 1930’s - High accuracy,
convenient - Requires contact
4. Liquid crystal thermography 0.3 – 1.0 5000 1960’s - Provides
thermal image - Requires contact Non-Contact Methods
1. Computerized Infrared 0.05 75 000 1970’s - Non-contact - Expensive
telethermography static image, and static
computer image
data analysis
2. Advanced Infrared 0.005 100 000 1990’s - Non-contact - Expensive
computerized dynamic image,
telethermography computer data
analysis
e. Considerably less expensive than electronic telethermography units
DISADVANTAGES
a. Low or poor thermal sensitivity (0.3 – 1 0C).
b. Skin surface has to be blackened c. The process is technique sensitive
d. Require carefully timed skin contact to record a reproducible temperature distribution
e. The spatial resolution of the liquid crystal display is poor (> 5mm)
Fig. 1: Full body Thermographic Image
Fig. 2: Thermo graphic image of face
In spite of its severe limitations, liquid crystal thermography has been claimed to yield meaningful results in the evaluation of thermal abnormalities of the face due to orofacial disorders.
NON-CONTACT METHOD INFRARED THERMOGRAPHY
JOHN FREDRICK WILLIAM HERSCHEL recorded infrared wavelengths and introduced the term “Thermograph”.
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THE EQUIPMENT i. Detector system
There are two categories of detectors. They are a. Thermal detectors: Thermal detectors suitable for
clinical use sense radiation by the temperature rise in the absorbing element, which affects some temperature-sensitive property. Pyroelectric detectors have the advantage that they can detect long wavelength radiation without detector cooling which is required for photon detectors.
Recently pyroelectric detectors have been incorporated into VIDICON type TV tubes.13 b. Photon detectors:
Indium antimonide (InSb) and cadmium mercury telluride (usually referred to as CMT) are the photon detectors most often used in clinical thermography equipment.
ii. Imaging Systems
Scanning of the scene in front of the detector can be accomplished by a variety of ways example, the Aga Thermovision 680 Medical camera or other systems like oscillating mirrors and rotating multi-sided mirror drums. The thermal picture is usually displayed on a television image tube.
More recently, serial scan systems have been developed in each detector in a linear array scan in sequence over every point in the scene, and the signals are appropriately delayed and added to form the image.
iii. Display systems
The signal derived from the detector is amplified and used to modulate the intensity of the electron beam of a TV monitor type picture-tube display unit. The thermal image shows relative temperature differences in a continuous range of gray tones from black to white. The hot area to be displayed may be white or black (inverted mode) depending on the preference of the user.
Fig. 3: Thermographic image of hands
Fig. 4: Thermographic image of legs
Fig. 5: Thermographic image of inflamed face
GENERAL CONSIDERATIONS PREPARATION OF THE PATIENT
Clinical thermography should be carried out in a draught-free, constant temperature environment. A
cool ambient temperature of 19+/-10C is the optimum to ensure reliable standardization and operation of the imaging equipment. It is important to strictly follow as many of these factors,
1) Expose the area of examination.
2) Keeping the subject at rest for 12-15 minutes in constant temperature (70-750C) room.
3) Keeping the room free from air currents and heat generating objects1.
4) Subjects being investigated by thermography must have clean, dry skin free from cosmetic cream. Perspiration on the skin reduces the apparent surface temperature.13
Thermographic feature suggestive of abnormality is localized area of temperature increase either unilateral or bilateral of about 1.5K or more on over the suspected pathologic area.13
Blood vessels which lie within 2 or 3 mm of the surface can be imaged photographically using reflected light and infrared sensitive film. Fat in contrast to muscle is a poor conductor, on the thermogram skin over the fat appears colder than skin over muscle. Hair is avascular and appears as “cold spots”. Conversely skin over muscle large veins, bruises, hematomas, infections and injuries appear as “hot spots”. Heavy scar tissue and uninfected cysts appear cold as a result of low metabolism and relative avascularity.15
Since its first application Infrared thermography has shown considerable potential within a number of dental disciplines including Periodontology, Restorative dentistry, Prosthodontics, Oral surgery and Oral Medicine.
SOME AREAS OF RESEARCH AND APPLICATIONS
i. Breast cancers (by Lawson, 1956)11, 15
ii. Diagnosis and management of malignant melanoma
iii. To quantitate the inflammation present in Osteoarthritic joint and in sacroiliac region iv. To determine the vitality of teeth and Atypical
odontalgia
v. Obstetric application
vi. For screening for cancer, management of burn or wound healing16
vii. To study rheumatic and other orthopedic diseases, cerebrovascular diseases, and ophthalmic disease5
viii. To evaluate dermatologic diseases5
ix. For the quantification of the effects of post-surgical inflammation, dental analgesics, and anti- inflammatory drugs, etc.
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x. In alveolar bone during implant site bone surgery.
xi. Useful in the diagnosis of myofascial symptoms associated with temporomandibular disorders etc.
USES
Thermography is being used to investigate a variety of clinical problems. The most important amongst these are:
1) Screening for occult malignant disease.
2) Delineation of the extent of known disease.
3) Identification of areas with abnormal temperatures, which might be the cause of functional impairment of underlying organs or glands.
4) Monitoring the effects of various forms of therapy such as reconstructive surgery, radiotherapy or treatment with hormones or drugs.
5) Assessing the prognosis of certain disease.
6) Identify functional deficiencies and vascular disorders.
7) Studying the effects of acute or chronic trauma.
8) Physiological research such as energy metabolism and peripheral vascular investigations.13
FACIAL TELETHERMOGRAPHY The normal facial telethermograph
Heat emissions from the human face have been shown to be physiologic indicators of underlying health or disease. Heat emission is directly related to cutaneous vascular activity, yielding enhanced heat output on vasodilatation and reduced heat output on vasoconstriction. Infrared telethermography of the face may serve, therefore, as an utterly harmless non-invasive diagnostic technique that can help to differentiate selected clinical problems.6
Overall thermal symmetry usually is present in the face and neck regions of normal subjects. Areas of highest thermal symmetry include the nasal, infra- mandibular, inferior labial, inferior buccal, superior buccal, superior buccal and TMJ regions of the face and neck. The posterior neck and temporal region of the face demonstrated the lowest degree of thermal symmetry. Electronic thermography has potential for use as an alternative diagnostic technique in dentistry.7
Fig. 8: Thermographic image of breasts
THE ABNORMAL FACIAL TELETHERMOGRAPH
There has also been interest in the application of thermographic methods to the study of oral and para- oral lesions.
i) Chronic orofacial pain patients
Recent clinical studies have successfully assessed the application of telethermography on patients with chronic oral and or facial pain of greater than 4 month’s duration.
ii) Assessing TMJ disorders
The most widely studied application of thermography to the orofacial region has been in the characterization of craniomandibular disorders, particularly TMJ dysfunction.4
TMJ pain patients were found to have asymmetrical thermal patterns, with increased temperatures over the affected TMJ region of their face. Specifically, painful TMJ patients with internal derangements and painful TMJ osteoarthritis were both found to have asymmetrical thermal patterns and increased area temperatures over the affected TMJ region of their faces.
The recent dental literature on majority of telethermography studies demonstrated a strong correlation between pain and local hyper perfusion or hyperthermia.6
ii) In oral inflammatory conditions
There are few dental studies. In one thermography was used to help determine the vitality of teeth. Results showed that firstly there was no correlation between electric pulp test readings & infrared temperature and secondly decayed / filled tooth surfaces & infrared temperature. One positive result was with a clinical abscess case15.
Thermography when used in odontogenic inflammatory conditions, the results showed the technique to be effective in active cases of disorders like periodontitis, periostitis, osteomyelitis, abscess and cellulitis15.
Thermography found that the normal surface temperature of the mucosa was significantly cooler than the temperatures of the inflamed areas in subjects with lesions induced by chemotherapy. Infrared thermography may allow measurement of tooth vitality to be based on blood supply rather than nerve supply. Thus it could be reliable method of vitality
testing after transplantation. There was temperature gradient from the gingival margin to the incisal edge of approximately 2.50C. The gingival margin of the teeth is at approximately 290C whereas incisal edge is at approximately 27.50C at an ambient room temperature of 210C.
Thermography is a promising aid in the diagnosis of atypical odontalgia 8 and internal derangement of TMJ.
Other physical disorders that have been reported to produce abnormal facial thermograms and that are potentially related to craniomandibular problems with myofascial pain syndromes, myositis, musculo- ligamentous injury, motor and sensory radioculopathy, herniated disc disease and the inflammation of arthritis and bursitis.8
RECENT DEVELOPMENTS AND FUTURE PROSPECTS
i) Pyroelectric vidicon camera ii) Microwave Thermography
iii) Dynamic Area Telethermometry (DAT) iv) Digital Infrared Thermal Imaging (DITI)
CONCLUSION
The application of temperature measurement and thermal imaging to assess health and disease (medical thermology) has continued to advance since antiquity up to the present day. The use of thermography has been minimal principally due to technological inadequacies of previous thermal imaging system.
However with the ever-developing advancement in technology, current systems are capable of producing real time highly sensitive digitized thermal images.
This development has led to take an increased use of newer thermographic imaging both medical and dental research.
REFERENCES
1. Anbar M, Gratt BM, Hong D. Thermology and facial telethermography. Part I: history and technical review. Dentomaxillo facial Radiology.
1998, 27: 61-67.
2. Barnett ML et al. Computer based thermal imaging of human gingiva. Journal of Periodontology. 1989; 60: 628-633.
3. Berry DC. Variations in skin temperature of face in normal subjects and in patients with mandibular dysfunction. Br J of Oral Surg. 1971;
8: 242-247.
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4. Biagioni PA et al. Infraredthermography: Its role in dental research with particular reference to craniomandibular disorders. Dentomaxillofacial Radiology. 1996; 25: 119-124.
5. Curcio RTBM. Pararadiologic imaging modalities: Ultrasonography and thermography.
In Merill V, editor. Atlas of roentgen graphic positions and standard radiological procedures.
Saint Louis, the Mosby Company, 1975. 4th edi, 3rd vol.p.954-959.
6. Gratt BM, Anbar M, Thermology and facial thermography: Part II. Current and future clinical applications in dentistry. Dertomaxillofacial Radiology. 1998, 27: 68-74.
7. Gratt BM, Pullinger A, and Sickles EA, and Lee JJ, Electronic thermography of normal facial structures: a pilot study Oral Surg Oral Med Oral Pathol. 1989, 68: 346-51.
8. Gratt BM, Sickles EA and RossJB Electronic thermography in the assessment of internal derangement of the TMJ. Oral Surg Oral Med Oral Pathol. 1991; 71: 364-70.
9. Gratt BM, Sickles EA, Groff-Radford SB and
Solberg WK. Electronic thermography in the diagnosis of atypical odontolgia. A pilot study.
Oral Surg Oral Med Oral Pathol. 1989, 68:
472-481.
10. http://www.ami.com.au/~lifetronics/crt/
crt.htm
11. http://www.infraredtraining.net 12. http://www.meditherm.com
13. Jones CH in PNT wells scientific basis of medical imaging, Thermographic imaging, P 194 – 210, 1st ed., 1982: P 194 – 210, Churchill living stone.
14. Pogrel MA, Erbez G, Taylor RC, Dobson TB, Liquid crystal thermography as a diagnostic aid and objective monitor for TMJ dysfunction and myogenic facial pain. J Craniomard disorders: Fac Oral Pain. 1989, 3: 65-70.
15. Soffin CB, Morse DR, Seltzer S, Lapayowker MS.
Thermography and oral inflammatory conditions. Oral Surg Oral Med Oral Pathol. 1983;
56: 256-262.
16. White A et al. The use of infrared thermography in the evaluation of oral lesions. JADA.1986;
113: 783-786.
Correspondence Address:
Ms. Anupama Sharma Assistant Professor
International Institute of Health Management Research Sector 18A, Dwarka, New Delhi
Fax: +91-011-30418909, Office: +91-011-30418900 Mobile: +91-9958293008, Email : [email protected] Website: www.iihmr.org
INTRODUCTION
Globally, it is estimated that about 33 million people are living with HIV/AIDS in 20071. In the Philippines, about 8300 people are estimated to be living with HIV/AIDS by the end of 20072. The first case of HIV/AIDS in the country was detected in 1984, since then the number of Filipinos infected with the virus has been on the rise3. Health experts describe the potential epidemic to be “growing but hidden”4. This growing number of HIV/AIDS cases may be due to apparent lack of public awareness of the virus. As the country is primarily inhabited by Catholics, religion holds a powerful key in shaping the ethical and moral norms of its populace. It is also a well known fact that, visit to spiritual places and adhering to religious practices and beliefs provides hope and gratification to individuals suffering from chronic
ailments including AIDS. Studies have noted that religion practices increase treatment adherence for individuals suffering from chronic ailments including AIDS5-7. This research is significant in exploring the current perceptions of church leaders and their strategic roles to fight against the virus and attached stigma. Three key aspects were explored in this study viz., initiatives taken by four major Christian groupings towards HIV and AIDS, opinions and beliefs of these church leaders towards HIV prevention, care and support activities and, factors acting as constraints to fight against the spread of the virus.
METHODS
Data was collected for a period of seven weeks during a field visit to Metro Manila. Leaders from four major Christian denominations were interviewed throughout Metro Manila including, Manila City, Pasay City, Paranaque, Valenzuela City and Quezon City. The study was exploratory in nature and included 20 sites and interviewed 24 church leaders. Only urban churches were selected on the basis of purposive sampling due to ease in accessibility. The sample however includes both male and female respondents in order to avoid any gender biasness.