This guideline was prepared by members of the American Academy Of Thermology (AAT) as a guide to aid the performance of medical infrared imaging in evaluating patients with neuromusculoskeletal complaints. It implies a consensus of those substantially concerned with its scope and provisions. The AAT guideline may be revised or withdrawn at any time. The procedures of the AAT require that action be taken to reaffirm, revise or withdraw this guideline no later than three years from the date of publication. Suggestions for improvement of this guideline are welcome and should be sent to the executive director of the American Academy of Thermology. No part of this guideline may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.
Sponsored and published by:
The American Academy of Thermology
500 Duvall Drive
Greenville, SC 29607
Telephone: (864) 236-1073
Copyright AAT. Do not Copy without permission.
2013, Updated 2016
Tracy A Turner, D.V.M., M.S.
Tracy A Turner, D.V.M., M.S., James Waldsmith, D.V.M., Ken Marcella, D.V.M., Kim Henneman, D.V.M., Ram C Purohit, D.V.M., Ph.D., Dominic Morino, D.V.M., Robert G. Schwartz, M.D., James Campbell, MD, Jan Crawford, BSN, Eduardo Borba Neves, PhD, Irma Wensink.
Internationally Peer Reviewed
Statement of Need
Heat is a cardinal sign of inflammation. Vasomotor tone and vasomotor capacitance plays a significant role in thermoregulation, clinical symptomatology and manifestations of systemic illness. In the Animal Kingdom the clinical manifestation of pain can be detrimental to survival. As such, changes in the previously mentioned vascular parameters may be the only clinical signs shown.
Infrared Thermal Imaging is the only non-invasive technology available to image and map circulatory changes associated with these disorders. It can play an important role in clinical diagnosis and enhance the clinical examination. But infrared imaging may also be valuable to document musculoskeletal stress caused by training as well as circulatory effects of therapeutic modalities. In addition, infrared imaging can be used as an aid in the regulation of the animal industry.
Other technologies such as Radiography, Ultrasonography, Scintigraphy, and MRI do not provide the same information offered by Medical Thermal imaging. The clinical application of Infrared Thermal may be instrumental in understanding the pathophysiology associated with veterinary musculoskeletal disease and improve patient outcomes.
The mission and bylaws of the American Academy of Thermology support the incorporation of thermal imaging into veterinary clinical medicine. The AAT recognizes a current and ongoing need to promulgate continuing education in the science and methods of thermal imaging and the clinical application of heat asymmetry patterns obtained from thermal imaging among both veterinarians and thermal technologists.
Veterinary medicine is a unique branch of the health sciences that involves multiple species many of which are not domesticated. Regardless, any can be dangerous to the examiner. Furthermore, veterinary patients do not seek medical attention, rather the owner, rider, trainer, or caretaker seeks medical advice based on their observations. Thus, veterinary examinations must be very thorough with attention to basic clinical signs that provide insight to potential inflammatory conditions. Unfortunately, many veterinary patients can only be examined using anesthesia or sedation. The ability of infrared imaging to detect changes in the heat patterns of skin make it an invaluable tool in the clinical assessment of veterinary patients with certain types of problems. The thermal examination can be performed from the cranium to the base of the spine, from the torso to the extremities, including the digits and may include the oral and abdominal cavities.
There are 4 common uses for infrared imaging in veterinary medicine (1-35)
- As a diagnostic aid where changes in the thermal patterns of scanned areas suggest a regional diagnosis whereby anatomic imaging modalities can then be used to characterize the nature of the problem
- As a method to enhance clinical assessment of the veterinary patient to include:
- Evaluation or follow-up of patients with known or suspected vasomotor instability.
- Pre-procedure assessment to aid in the planning of interventional therapeutics or diagnostics
- Follow-up to detect improvement, progression or spread of disease, which may reflect change in condition.
- Evaluation of muscle circulation
- Evaluation of post-surgical swelling and local circulation
- Evaluation of unexpected post-operative or post fracture pain.
- Qualitative assessment of the vasculature and blood flow to tissues
- Evaluation of peripheral neuropathies.
- Evaluation of inflammation associated with dental or periodontal disease
- To determine if areas of palpable soreness are associated with changes in temperature
- Monitoring of extremities post cast application
- Monitoring progression and appropriateness of exercise protocols through the post-injury rehabilitation process.
- As a method to assess musculoskeletal stress in working/performance animals during training, travel & performance including but not limited to:
- Identification of the presence of subclinical inflammation to allow for appropriate intervention.
- Assessment of hoof and shoe balance in horses.
- Assessment of saddle & harness fit in horses.
- Assessment of the effects of the rider on the horse’s back.
- Evaluation of the ergonomic fitness of harnesses, thermal control/equipment vests and foot protection booties in performance and working animals.
- Identification of the onset of hyperthermia in performance and working animals.
- For regulatory medicine to determine welfare compliance in jumping horses and Tennessee Walking Horses (TWH) including but not limited to:
- Assessment of limb temperature changes for limb sensitivity in show jumpers
- Identification of abnormal cold on the distal limb of TWHs suggestive of foreign substance application
- Assessment of thermal patterns on the palmar pastern of TWHs suggestive of abnormal scar formation
- Assessment of thermal patterns of TWHs distal limbs consistent with application of “soring” agents
Contraindications and Limitations
Infrared thermal imaging shows only skin temperature and therefore is a reflection of the deeper tissues.
Infrared imaging is highly sensitive to environmental factors and an understanding of these factors is imperative if infrared imaging is to be successful.
- Infrared imaging is contraindicated if the thermal evaluator does not understand infrared radiation physics
- Imaging is contraindicated if bilaterally symmetrical images cannot be evaluated.
- Imaging is contraindicated if environmental factors cannot be controlled, including sunshine, ambient temperature, drafts, haircoat, topical moisture, topical liniments, and the presence of bandages or blankets or articles of harness.
- Imaging is contraindicated if the patient is uncooperative.
Guideline 1: Owner (Person Responsible) Communication and Veterinary Patient Preparation:
1.1 The examiner explains the medical necessity for performing infrared imaging to the Person Responsible (PR) for the Patient.
1.2 Responds to questions and concerns from the PR about any aspect of the examination.
1.3 Advises the PR about risk factors and the information hoped to be obtained by infrared imaging. Obtains informed consent either written or orally from the PR to proceed with infrared imaging.
1.4 Refers specific diagnostic, treatment or prognosis questions to the Veterinarian.
1.5 The Patient should be as clean as possible and groomed to remove any debris from the body surface. Patient should not have contact with any object if that body part is being imaged. All leg wraps, bandages, blankets, or any other object having contact with the area of anatomy to be examined should be removed for a minimum of 20 minutes prior to the commencement of the Thermal Exam. Animals should not be touched or allowed to sit or lay down.
1.6 Avoid placing any material of any kind on the skin, such as any skin lotions, liniments, fly spray, topical external parasite treatments, etc. The haircoat must be dry.
1.7 The PR should declare the presence of any vasoactive topical or systemic substances to the examiner. Whenever possible steroids, sympathetic agonists and antagonists, vasoactive medications, opiates and transdermal patches should be avoided for 24 hours prior to testing. Exceptions should always be recorded in the record.
1.8 Avoid skeletal manipulation, acupuncture, massage therapy, the use of TNS or electric muscle stimulation units, therapeutic ultrasound, shockwave, compression devices, icing, or any type of therapeutic device or treatment. Exceptions should be noted in the record.
1.9 In the absence of extenuating circumstances, diagnostic studies using neurolytic blocks should be avoided for 3 days prior to testing.
1.10 Controlled exercise such as riding, lunging or treadmill for horses, play, running or treadmill for dogs are useful dynamic examinations part of the thermographic evaluation but must be performed in a controlled manner. Intense exercise should be avoided in all animals for at least 2 hours prior to a resting examination.
Guideline 2: Patient Assessment
Patient assessment should be performed before infrared imaging.
2.1 Obtain a complete, pertinent history by interview of the PR and/or review of the patient’s medical record. A pertinent history includes:
a. Current medical status, especially regarding pain, lameness, and possible vascular issues.
b. Presence of any signs or symptoms of vasomotor or other autonomic dysfunction.
c. Relevant risk factors for injury, age, use, breed
d. Pathology/Laboratory investigation values.
e. Current medication or therapies
f. Results of other diagnostic Imaging modalities, radiographic, sonographic, scintigraphic, thermographic, computed tomography or magnetic resonance studies
g. Results of prior treatments
2.2 Veterinarians should complete a limited, focused, detailed or extensive physical examination, which includes assessment of all structures under study. The extent of the examination may be dependent on the tractability of the veterinary patient. Veterinary assistants should follow policy and procedure of the interpreting or attending veterinarian.
2.3 Compliance with Federal, State or other applicable regulatory rules and regulations should be maintained.
Guideline 3: Examination Guidelines
3.1 Infrared imaging measures and maps the degree and distribution of IR thermal emission. Skin temperature is largely under the control of the autonomic nervous system and inflammatory processes. Sagittal symmetry is expected throughout the body. Asymmetric IR emission of 1°C or greater can be indicative of sympathetic nervous system (SNS) dysfunction or other pathology.
Infrared evaluations do not test structure, but rather correlates to sympathetic nervous system physiology as well as local or systemic inflammation. Therefore, when structural injury is suspected additional radiographic imaging or diagnostic studies may still need to be performed.
Due to the complex nature and etiology of painful conditions associated with skin temperature asymmetry patterns, only those veterinarians trained in the proper techniques required to perform and interpret infrared imaging should do so. When present, the pattern of asymmetry discovered by infrared examination should guide the treating veterinarian in determining the source or generator of the abnormality. Both response to treatment and additional examination or testing may still be required to complete this task.
3.2 The following minimum specifications should be incorporated in the design of infrared hardware and software systems. These specifications are intended to speak to the design of modern infrared imaging equipment that are considered commonplace today. They are not intended in any way reflect on systems used in the past.
- Emissivity set to 0.98 (human skin). A setting of 1.0 is acceptable for mammalian skin.
- Camera detector(s) response above 5 and below 14 microns
- For cooled cameras an Absolute detector resolution of >640 X 480 coupled with a suitable lens. Most modern medical imaging systems today utilize uncooled focal plane array detectors found in the 320 X 240 sensor range or higher. When systems with 320 X 240 sensors are coupled with lens and software or firmware innovations they can approach the image quality, spatial resolution and spot measurement requirements found in 640 X 480 systems.
- Minimum measurable spot size is 2.1×2.0 mm at 40 cm distance (3×3 or 9 pixels).
- Spot resolution quality at 8 feet equivalent to ≤ 1 sq. mm at 40 cm from the detector(s).
- Spatial resolution quality at 8 feet equivalent to ≤ 2.6 mRad IFOV (Instantaneous Field of View) at 40 cm minimum focus.
- Thermal sensitivity of ≤ ± 50 mK NETD (Noise Equivalent Temperature Difference) @ 30 0
- Ability to perform accurate quantitative differential temperature analysis with a precision of ≤ ± 0.05 0
- Repeatability and precision of ≤ ±05 0C detection of temperature difference. The repeatability of a differential measurement must be in the presence of +/- 3 NETD (6 sigma – 99.9% defect free mfg. standard).
- Changes in external ambient temperature to be strictly controlled at natural convection at or below 0.2 m/s.
- Thermal drift (caused by internal heating of equipment during normal operation or by changes in external ambient temperature) to be strictly controlled at natural convection at or below 0.2 m/s.
- Maintenance of detector uniformity and correction via calibration.
- Ability to render images in hi-resolution color and grayscale.
- High-resolution image visual display for interpretation.
- Real time image focus and capture capability. While 10Hz, 20Hz, and 30Hz are capable of real time imaging faster capability is preferred (50Hz).
- Temperature range set to cover temperatures within the range of mammalian emissions (20-45 0C).
- Typically, ranges of 10°C are utilized but this range can be adjusted as needed to cover the range of skin temperature.
- Ability to archive images for future reference and image comparison at same patient positioning and distance from the camera.
- Software manipulation of the images should be maintained within strict parameters to insure that the original qualities of the images are not compromised
- Imaging software capable of identifying areas of calculations and locations for reporting.
- Appropriate infrared instrumentation, which includes real time display, electronic static image capture, storage, post capture annotation or hard copy documentation capabilities, should be utilized.
3.3 All studies should be performed in an environment in which, to the extent possible, ambient temperature is controlled, free from drafts and where there is no exposure to infrared rays, such as incandescent lights or sunlight that may result in heating or reflective artifacts. The imaging room should be comfortably cool to allow for dissipation of superficial heat which may produce artifact from the skin. Ideally the ambient temperature range for IR imaging suite should be between 20° to 25°. However, as long as it is below 30º C and sweating is not induced, thermal imaging may be performed.
3.4 Ventilation systems should be designed to avoid direct airflow onto the patient. The patient should not be placed near or under any light fixture that itself emits heat. Standard fluorescent and/or LED lights are appropriate.
3.5 Infrared studies can usually be accomplished with one set of images, however, post exercise examination or saddle test examinations require more than one set of images. Images taken in these serial studies should have accompanying time stamps for clarity.
3.6 A standard exam protocol for each segment evaluated should be used. Each point of focus should include dorsal, palmar/plantar, medial, and/or lateral views, as required. Contralateral and dorsal views should be equidistant and fill the image screen. When possible, it is recommended that the contralateral extremity images should be captured in the same image as the extremity under examination. Obtaining additional images may be required for patients with specific, unique circumstances.
3.7 The patient’s physical and mental status is assessed and monitored during the examination, with modifications made to the procedure plan according to changes in the patient’s clinical status during the procedure. Also, findings are analyzed throughout the course of the examination so that the veterinarian is provided sufficient data to direct patient management and render a diagnostic impression.
3.8 Appropriate infrared instrumentation, which includes real time display, electronic static image capture, storage, post capture annotation or hard copy documentation capabilities. It is further recommended that static image files be available for viewing and storage, either as JPEG images stored in a unique folder for each animal patient, or in Digital Imaging and Communications in Medicine (DICOM) format for Picture Archiving and Communication System (PACS) distribution.
3.9 Evaluate the patient’s physical and mental status prior to discharge. Additional discharge instructions to the PR may include recommendation to schedule follow up appointment with the attending veterinarian, and to resume all medication medical treatment that may have been discontinued prior to the infrared study.
Guideline 4: Review of the Infrared Thermography Examination
4.1 The data acquired during the extremity and spinal infrared examination should be reviewed to ensure that a complete and comprehensive evaluation has been performed and documented. Any exceptions to the routine examination protocol (i.e., study omissions or revisions) should be noted and reasons given.
4.2 The examiner should record all technical findings required to complete the final interpretation so that the measurements can be classified according to the standard laboratory diagnostic criteria.
4.3 The examiner should complete the required documentation of the study in a timely manner.
4.4 The examiner should alert the medical director or other responsible veterinarian when immediate medical attention is indicated, based on the infrared examination findings.
Guideline 5: Presentation of Exam Findings
5.1 The examiner must provide preliminary results as provided for by internal policy based on examination findings.
5.2 The examiner must present the record of diagnostic images and when applicable, explanations for sub-optimal examination findings to the interpreting veterinarian for use in diagnosis and archival purposes.
5.3 The examiner must alert the laboratory medical director or appropriate health care provider when immediate medical attention is indicated.
Guideline 6: Preparation and Storage of Exam Findings
6.1 Images should be presented to the interpreting veterinarian for use in analysis and archival purposes. Radiometric images in either radiometric image format or radiometric image convertible format such as JPEG or DICOM are acceptable. A color-to-temperature Thermal Scale must accompany each image.
6.2 The imaging clinic should adhere to all established federal and state regulations. Archiving of image data and the analysis/report are to be maintained for no less than seven years.
Guideline 7: Exam Time Recommendations
High quality and accurate results are fundamental elements of the infrared study. A combination of direct and indirect exam components is the foundation for maximizing exam quality and accuracy.
7.1 Indirect exam components include pre-exam procedures:
a) obtaining previous exam data, completing pre-exam paperwork,
b) exam room and equipment preparation and
c) patient assessment, history, and positioning.
7.2 Post exam procedures include:
a) clean up consisting of compiling, processing, and reviewing data for preliminary and/or formal interpretation ,
b) PR communication,
c) examination charge and billing activities where appropriate.
Recommended time: 30-60 minutes.
7.3 Direct exam components include:
a) equipment optimization,
b) patient positioning throughout the exam,
c) the actual hands-on examination process.
Recommended time: 20-60 minutes.
Guideline 8: Reporting
8.1 A medical record report should be prepared within 24 hours of the study. As part of the imaging protocol, the thermographer should consider sending each PR a summary report within 30 days of the thermographic examination.
8.2 Report layout: The body of the Infrared Veterinary Thermographic report should clearly state that procedures that follow a peer reviewed, internationally accepted guideline was utilized. The set of images obtained for study should be documented. If a standard protocol for reading images is used then this should be stated as well.
Thermographic Findings should be documented and any abnormalities noted. Findings include asymmetry of > 1 degree Centigrade in > 25% of the surface area of any individual region of interest and localized hot or cold spots.
Thermographic impressions include classification according to an accepted naming system or summarization of the thermographic findings. When recognized patterns (thermal signatures) are seen, the thermographic impressions may include the description of that pattern (for example: a back thermographic pattern consistent with overriding vertebral spinous processes) however care should be taken not to make any statements about clinical diagnosis in this section of the report. That is these patterns have been associated with particular disease but the pattern does not prove the disease.
Clinical Impressions are not to be included in the Thermographic Findings paragraph but rather in a separately identifiable paragraph that speaks to the generator or etiology of those findings. Any discussion that is clinically relevant should be reserved for this paragraph.
Guideline 9: Continuing Professional Education
Certification is considered the standard of practice for infrared technology. It indicates an individual’s competence to perform medical technology at the entry level. After achieving certification, all Registered Infrared SSR Technologists are expected to keep current with:
9.1 Advances in diagnosis and treatment of pain syndromes with and without sympathetic nervous system dysfunction (vasomotor instability).
9.2 Changes in infrared examination protocols or published laboratory diagnostic criteria.
9.3 Advances in infrared technology used for veterinary examinations.
9.4 Advances in other technology used for infrared examinations.
Guideline 10: Emerging Technologies
10.1 Technology is constantly being introduced that at times can challenge existing guidelines or that do not necessarily conform to currently accepted practices. These technologies can span the entire spectrum of sophistication and therefore require different adaptive responses. On one end of the spectrum there are innovations based upon generally accepted medical scientific methodology that have gained regulatory acceptance and on the other end there are technologies that are intended for personal use only or that have applications in non-medical fields but have not been accepted as suitable for medical practice.
10.2 General industrial or personal thermal imaging cameras that do not meet the specification guidelines contained herein are not intended for use in Medical Thermology.
10.3 Technologies not otherwise covered in these Guidelines that employ methodologies, hardware, or protocols that have gained Federal Regulatory approval for Medical Thermology may become available however over time. In cases where these technologies are employed the body of the report should document which deviations occurred and why, and other components of the Guideline should still be followed.
- Turner TA, Fessler JF, Lamp M, Pearce JA, Geddes LA: Thermographic evaluation of horses with podotrochlosis. Am J Vet Res 44(4):535-539, 1983.
2. Loughin CA, Marino DJ: Evaluation of thermographic imaging of the limbs of healthy dogs. American Journal of Veterinary Research, 68(10): 1064-1069, 2007.
3. Ringer SK, Lischer CJ, Ueltschi G: Assessment of scintigraphic and thermographic changes after focused extracorporeal shock wave therapy on the origin of the suspensory ligament and the fourth metatarsal bone in horses without lameness American Journal of Veterinary Research , 66(10): 1836-1842, 2005.
4. Purohit RC, McCoy MD. Thermography in the diagnosis of inflammatory processes in the horse. Am J Vet Res; 41:1167–1174, 1980.
5. Vaden MF, Purohit RC, McCoy MD, Vaughan JT. Thermography: a technique for subclinical diagnosis of osteoarthritis. Am J Vet Res; 41:1175–1179, 1980
6. Simon EL, Gaughan EM, Epp T, Spire M: Influence of exercise on thermographically determined surface temperatures of thoracic and pelvic limbs in horses, J Am Vet Med Assoc, 229:12, 1940-1944, 2006
7. Von Schweinitz: Thermographic diagnostics in equine back pain. Vet Clin North Am Equine Pract. Apr, 15 (1):161-77, 1999
8. Denoix JM: Diagnostic techniques for identification and documentation of tendon and ligament injuries. Vet Clin North Am Equine Pract. Aug ,10 (2):365-407, 1994
9. Turner TA: Diagnostic thermography,Vet Clin N.A.: Equine Pract. 17(1): 2001
10. Turner TA: Thermography as an aid to the clinical lameness evaluation,)Vet Clin of N.A.: Eq Prac, 7(2): 311-338, 1991
11. Turner TA: Hindlimb muscle strain as a cause of lameness in horses. 35th Annu Meeting of Am Assoc of Equine Practnr, 1989: 281-290.
12. Turner TA, Wolfsdorf K, Jourdenais J: Effects of heat, cold, biomagnets and ultrasound on skin circulation in the horse. 37th Annu Meeting of Am Assoc of Equine Practnr, 1991: 249-257
13. Waldsmith JK. Real-time thermography: a diagnostic tool for the equine practitioner. 38th Annu Conv Am Assoc Equine Pract 1992;38:455–466.
14. Turner TA: Use of thermography in lameness evaluation.44th Annu Meeting Am Assoc Eq Practnr, 1998: 224-226.
15. Tomlinson JT, Sage AM, Turner TA: Ultrasonographic examination of the normal and diseased equine pelvis. 46th Annual Meeting Am Assoc Eq Practnr, 2000: 375-377.
16. Turner TA:, Pansch J, Wilson JH: Thermographic assessment of racing Thoroughbreds. 47th Annual Meeting Am Assoc Eq Practnr, 2001: 344-346.
17. Turner TA: Back problems in horses. 49th Annual Meeting Am Assoc Eq Practnr, 2003: 71-74.
18. Turner TA, Waldsmith JK, Wilson JH: How to assess saddle fit in horses. 50th Annual Meeting Am Assoc Eq Practnr, 2004: 196-201.
19. Mogg KC, Pollitt CC. Hoof and distal limb surface temperature in the normal pony under constant and changing ambient temperatures. Equine Vet J 1992;24:134–139
20. Marr CM. Microwave thermography: a non-invasive technique for investigation of injury of the superficial digital flexor tendon in the horse. Equine Vet J 1992;24:269–273
21. van Hoogmoed L, Snyder JR, Allen AK, Waldsmith JD. Use of infrared thermography to detect performance-enhancing techniques in horses. Equine Vet Educ 2000;12:102–107.
22. Tunley BV, Henson FM: Reliability and repeatability of thermographic examination and the normal thermographic image of the thoracolumbar region in the horse. Equine Vet J. 2004 May;36(4):306-12.
23. Holmes LC, Gaughan EM, Gorondy DA, Hogge S, Spire MF: The effect of perineural anesthesia on infrared thermographic images of the forelimb digits of normal horses. Can Vet J. 44(5): 392–396, 2003.
24. Cockcroft PD, Henson FM, Parker C. Thermography of a septic metatarsophalangeal joint in a heifer. Vet Rec. 146:258–260, 2000.
25. Eddy AL, van Hoogmoed LM, Snyder JR. The role of thermography in the management of equine lameness. Vet J. 162:172–181, 2001.
26. Turner TA. Alternate methods of soft tissue imaging. Dubai Int Equine Symp: 165–176, 1996.
27. Waldsmith JK, Oltmann JI. Thermography: subclinical inflammation, diagnosis, rehabilitation, and athletic evaluation. J Equine Vet Sci.14:8–10, 1994.
28. Turner TA, Scoggins RD: Thermographic detection of gingering in horses. J Eq Vet Sci, 5(1):8-10, 1985
29. Turner TA, Fessler JF, Purohit R: Thermography: A review in equine medicine. Comp Cont Ed, 8(11):855-862, 1986.
30. Turner TA: Thermography as an aid in the localization of upper hindlimb lameness. Pferdeheilkunde, 12(4), 632-634, 1996.
31. Turner TA: Uses and limitations of thermography. Pferdeheilkunde, 12(4), 684-685, 1996.
32. Verna M, Turner TA, Anderson K: Scintigraphic, radiographic, and thermographic appearance of the metacarpal and metatarsal regions of adult healthy horses treated with non-focused extracorporeal shockwave therapy-a pilot study. Vet Therapeutics, 6(3): 268-276, 2005
33. Purohit RC, Pascoe DD, Turner TA: Use of thermography in veterinary medicine, in Bronzino JD (ed): The Biomedical Engineering Handbook, 3rd Edition, CRC, Taylor and Francis Publication, pp 35,1-8, 2006.
34. Purohit RC: Use of thermography in veterinary medicine, in Cohen JM and Lee MHM (eds): Rehabilitation Medicine and Thermography, Impress Publication,pp135-147, 2008.
35. Westermann S, Heinz H. F. Buchner, Johannes P. Schramel, et al.: Effects of infrared camera angle and distance on measurement and reproducibility of thermographically determined temperatures of the distolateral aspects of the forelimbs in horses. Journal of the American Veterinary Medical Association, Vol. 242 (3), 388-395, 2013.
36. Levet A, Martens L, Devisscher L, et al: Distal limb cast sores in horses: Risk factors and early detection using thermography. Equine Vet J, Volume 41 (1), 18–23, 2009.
37. Westermann S, Stanek C, Schramel JP, et al: The effect of airflow on thermographically determined temperature of the distal forelimb of the horse. Equine Vet J, doi: 10.1111/evj.12019 : 2013