Time:2019-05-08 Edit：Zhong rui
Medical infrared thermal imaging technology is a combination of medical technology, infrared camera technology and computer multimedia technology. It is an imaging device for recording the thermal field of human body. A person is a warm-blooded animal that can maintain a certain body temperature. From a physics point of view, the human body is a natural biological heating element that constantly radiates infrared radiation energy to the surrounding space. When the human body is sick or some physical conditions change, this systemic or local heat balance is destroyed and affected, so it is clinically expressed as an increase and decrease in tissue temperature. Therefore, we can monitor the occurrence and development of diseases by measuring the changes in body temperature, and provide a basis for clinical diagnosis. Many scholars at home and abroad also apply the characteristics of infrared thermography to health examinations.
一,The infrared sensor directly receives the infrared light radiated by the human body, and has no harm to both the doctor and the patient; the non-contact remote temperature measurement does not change any parameters of the target to be measured.
High temperature resolution (0.05 degrees), high spatial resolution (1.5mrad) and high frame rate (50 frames per second).
Digital image recording, rich image processing capabilities. The function of the instrument is the same as that of a digital camera, which can be used for continuous dynamic observation and comparison of temperature data at different times. It also utilizes modern computer and information technology, powerful image processing, and convenient data storage and copying. It is a low-cost, easy-to-check instrument. The cost of purchase is only comparable to that of ordinary B-ultrasound; the inspection process only requires the patient to expose the site to be tested at a stable ambient temperature (22 to 26 ° C) without suffering any pain. Any disease that causes thermal changes in human tissue can be used for examination, with a wide range of applications and high clinical value.
二、Second, the five diagnostic functions of infrared thermal imaging:
1. Early warning: When the disease develops to a certain extent, organic tissue structure and morphological changes will occur. Before the disease changes in structure and morphology, temperature changes will occur in the lesion area. The information collected by the infrared camera can be used to detect the lesions early in the hospital and pay close attention to the pathological development to win valuable diagnosis time.
2. Diagnosis of disease: Infrared heat map can provide the distribution of thermal field in the lesion, so as to infer its circulation and metabolic state, determine the nature, extent and involvement of the lesion, so as to make a correct diagnosis and treatment plan.
3. Monitoring curative effect, guiding treatment course: using infrared thermal imager to collect temperature changes related to disease information at any time, real-time monitoring of curative effect, timely guiding medical procedures, adjusting treatment plan; inflammatory state, metabolic state, blood circulation state after medication Improvements are assessed.
4. Follow-up observations, predictive lesions: Clinical practice has shown that there is a change in temperature distribution before changes in tissue structure and morphology occur in new areas of tumor metastasis. The location of this temperature distribution change can be checked in advance by an infrared camera to know in advance the new ward where the cancer cells metastasize.
5. Medical science exploration: Because the infrared camera showed the two-dimensional distribution field of various parts of the human body in front of the scientific research workers for the first time, they first saw some unknown phenomena. A new topic has been proposed for scientific research in many disciplines.
三、Third, the advantages of infrared thermal imaging diagnosis:
1. Tumor warning, full monitoring, efficacy evaluation
Tumor tissue is accelerated by early metabolism, blood circulation is increased, and the volume is increased enough to be distinguished by MRI, CT, etc., generally at least 3-6 months. When normal cells begin to malignant and the cells proliferate at a high speed, in order to meet the needs of cell growth, blood circulation is inevitably accompanied, and local vasodilatation is brought about by the action of tumor toxic factors. The result of the above changes inevitably leads to an increase in local temperature. Medical infrared camera, high sensitivity, when the temperature changes more than 0.05 ° C, it can detect and record this change, showing abnormal high temperature parts, timely warning, to win time for early diagnosis. When the patient has a clear diagnosis of the tumor, the infrared thermography is the most ideal means for monitoring and evaluating the whole process.
(1) Significance in the diagnosis of thyroid cancer
The thyroid gland is a gland that is closer to the body surface in the endocrine system. In the case of infrared thermal image detection, the surrounding heat source has less interference, and it is easy to find early changes in the calorific value, and it is easy to confirm the diagnosis in combination with its metabolism.
Wang Peiqing et al used the temperature difference of thyroid on both sides of 0.24 °C as an indicator of thyroid cancer. Combined with the cold load test (70% ethanol coated on both sides of the thyroid region, let it cool, observe the temperature rise process) positive indicators, the two complement each other, confirm each other, the diagnostic rate of thyroid disease is significantly improved, reaching 85.4% (88/103), as shown in Table 1.
Table 1 The number of positive indicators of thyroid cancer and benign lesions (example)
According to Table 1, it can be a malignant tumor if one indicator is positive. According to one indicator, the diagnostic compliance rate of thyroid cancer was 88.9% (32/36); the diagnostic coincidence rate of benign lesions was 83.6% (56/67). Infrared thermography has a theoretical basis for the diagnosis of thyroid cancer. It can display qualitative functions in clinical practice and has good practical value. Moreover, its examination data can help to analyze and judge the extent of the lesion and the development stage of the disease course.
According to the data reported by Willamns, 75 patients with breast cancer were observed for 5 years of continuous skin temperature changes. The skin temperature increased by 1-2 °C, the mortality rate was 37%, and the skin temperature increased by 3 °C. %. The change of infrared thermogram temperature can not only estimate its prognosis, but also can guide the dosage of chemotherapy drugs and the length of medication, which has important clinical value for improving the survival rate of postoperative patients with breast cancer.
2. Significance in determining the location, nature and degree of soft tissue pain
At present, no device can record pain. But because the pain area must be accompanied by or/or abnormal metabolic changes, or/and changes in nervous state, or/or changes in blood circulation, these factors will inevitably lead to changes in temperature. Therefore, infrared thermography can reflect the nature, degree and range of pain by recording the temperature changes accompanying pain.
(1) Significance in the diagnosis of lumbar disc herniation
In patients with lumbar disc herniation, CT and MRI can clearly show the position, extent, and anterior-posterior relationship of the disc herniation. However, based on the results of CT and MRI images, it is quite difficult to clarify the current degree, nature and extent of the patient's pain. Moreover, in most cases, patients undergo conservative treatment, and after the symptoms disappear, CT and MRI are taken again, and there is little change in imaging. However, the infrared heat map is different. When it is painful, local conditions may cause high temperature due to aseptic inflammation and congestion. With aseptic inflammation, improved hyperemia, and improved symptoms, this hyperthermia heat map will gradually return to normal.
Studies have shown that heat maps can indicate the specific location of the pain, the size of the lesion, and the extent of the pain. The lumbosacral pain area is a red high temperature area on the heat map; the symptoms of radiation pain, numbness, cold limbs, and decreased muscle strength of the affected limb are shown on the heat map as a decrease in skin temperature, a shift in color to the black direction, and a physiological condition. The disappearance of the hot zone and the diameter ratio of the healthy limb are greater than l. In addition, the heat map when the symptoms are alleviated or disappeared is compared with that before the treatment, the red hot zone of the lumbosacral region is reduced, the waist temperature is lowered, the color is lightened, the color of the affected limb is close to the color of the healthy side, and the skin temperature of the lower limbs is poor. In reduction, the diameter ratio is close to l. This indicates that the heat map changes before and after treatment are very large. This kind of image results can be directly displayed to both doctors and patients, and the efficacy can be evaluated objectively compared with the patient's self-conscious symptoms and general physical examination.
(2) Application in neck and shoulder pain
The causes of neck, shoulder, back and back pain are complex, and the clinical manifestations are diverse. There is often no consistent close relationship between symptoms, physical examination and X-ray image changes. Therefore, the diagnosis is difficult. In recent years, the application of infrared thermal imaging technology in the medical field has provided new ideas for this diagnosis. Infrared thermography can sensitively reflect the heat distribution and functional status of patients with neck, shoulder and back pain through changes in skin temperature, which is of great value for diagnosis.
Wang Sheng and other studies found that the normal thermal image distribution of the human body conforms to the normal anatomical structure, and the upper and lower sides are symmetrical. The thermal image of the trunk is characterized by high temperature along the center of the spine, and the temperature of the back sides is symmetric, and there is no obvious temperature boundary zone. The thermal image of the lower back of the patient with neck, shoulder and back pain presents a high-temperature or low-temperature region with obvious flaky shape on the affected side. The thermal image is obviously asymmetrical, showing an abnormal thermal image or an obvious abnormal thermal image. From the temperature point of view, the temperature difference between the neck point, the back point, the back side point and the waist point temperature measurement point of the control group were both <0.5 ° C, and the infrared thermogram was a normal thermal image. The temperature difference between the neck point, the back point, the back point and the waist point of the patients with neck, shoulder and back pain was significantly higher than that of the control group, the difference was significant (P<0.01), and the thermogram was an abnormal thermal image.
3. Significance in the determination of the location, extent and extent of acute and chronic inflammation
Inflammation is a very common pathological phenomenon, and redness, heat and pain are the most common manifestations of inflammation. Clinically, inflammation is determined by tests such as blood routine and erythrocyte sedimentation rate, but where inflammation is, this is often a very concerned issue in diagnosis. This problem can be solved more easily by using an infrared heat map. Studies have shown that in the case of acute inflammation, the temperature must be high temperature; in chronic inflammation, due to mechanical adhesion, local blood circulation declines, its temperature will drop; if acute inflammation of the acute inflammation, it can occur high and low temperature staggered The situation, etc.
4. Brain and limb vascular function monitoring
Infrared heat map to detect vascular lesions, especially the blood supply status and functional status of limb blood vessels have certain advantages. Where arterial lesions affect blood supply, the distal end must be low temperature; for venous lesions, the distal end must be hyperthermia due to blood stasis and congestion; when the blood vessel is disconnected, the blood supply area must have a corresponding low temperature; After the recovery, the blood supply control area must have rewarming. Infrared thermal images are more convenient and intuitive than other methods such as ultrasonic Doppler and picometer measurement.
(1) Significance in the diagnosis of thromboangiitis obliterans
Thromboangiitis obliterans is an inflammatory and thrombotic occlusion dominated by limb arteries, especially in the lower extremities. Previous examinations of stage I thromboangiitis obliterans in the lower extremities were based on laboratory hemorheology (such as hematocrit and electrophoresis, blood and plasma viscosity) and hemodynamic examination (eg vascular murmur, ultrasound, arteries). Contrast, etc.). However, these methods are poor in the diagnosis of the disease, and there is still a lack of judgment on the extent of the disease. Infrared thermography has a high diagnostic value for determining the location of limb arterial occlusion and the degree of ischemia.
Wang Peiqing et al examined the lower extremities of 47 patients with lower extremity thromboangiitis obliterans and 21 normal subjects with infrared thermography. It was found that the normal human thermal image showed no significant difference in skin temperature between the lower limbs, the center of the thigh and calf was reddish, the surrounding area was green, the knee was light green, and the back of the foot was pale blue. The lower extremity thermal image of the affected limb of patients with lower extremity thromboangiitis obliterans is significantly different from that of normal people. Because the lesions appear on both sides of the lower limbs, the low temperature area is mixed with the non-low temperature area, the high temperature color is red in the phlebitis area, and the low temperature color green appears in the thrombus area, so uneven plaques appear on the thermal image. The temperature distribution of the affected limb is disordered, and the temperature difference between the high temperature zone and the low temperature zone is above 0.5 °C. The back of the foot and the toes are low-temperature blue. Moreover, using the temperature difference between the lower limbs, it was found that patients with long course of disease and severe disease had large temperature difference between the lower limbs; patients with short course and mild disease had small temperature difference between the lower limbs. Therefore, the temperature and image displayed by the thermal image group reflect the circulation state of the blood and the severity of the condition.
5. Other
(1) For some gynecological diseases, prostate diseases, and diseases of brain tissues, blood vessels and other organs, due to its deep position, soft tissue imaging cannot judge its functional status, and the examination is time consuming and laborious. The infrared camera is clear at a glance, and the inspection is convenient and fast. In addition, in the case of limb amputation, replantation of severed fingers, observation of burn degree, determination of skin graft survival, judgment of common diseases of ENT, physical examination of gland function, etc., because the test is non-contact, non-invasive, Convenient and accurate, so there will be a vast world of its own clinical.
(2) Infrared thermal imaging technology has also played an invaluable role in the monitoring and early warning of some major infectious diseases. During the epidemic of atypical pneumonia, China uses infrared thermal imaging cameras to detect the body temperature of each person in the normal state of circulation without touching the human body, and to alarm and lock the target to the abnormal temperature. It greatly facilitates the investigation of abnormal body temperature and has produced enormous social and economic benefits. Recently, the equipment successfully developed by Chongqing Weilian Technology Co., Ltd. has been listed as a national-level scientific and technological achievement promotion project by the Ministry of Science and Technology and listed as a high-tech industrialization project by the State Planning Commission.
Ⅳ ideal, complete imaging diagnosis
Infrared thermography is a category of functional imaging diagnostics. If combined with structural imaging such as CT, MRI, and B-ultrasound, it can understand the patient's organizational structure and understand the functional status of the tissue. In other words, the combination of structural imaging and functional imaging is the ideal modern imaging. The combination of the two will lead to early detection of many lesions, a more comprehensive understanding of the disease, and a more accurate diagnosis of the nature of the disease.
V. Problems and prospects
Infrared thermal imaging technology is an emerging functional imaging diagnostic technology. It was favored by medical workers because of its convenient use, non-invasiveness and high diagnostic accuracy. However, any instrument is not omnipotent, it also needs further improvement. (1) Skin thickness, fat thickness, tissue vitality, and stage of disease are all factors that affect the rate of diagnosis. Medical workers should conduct extensive communication with engineering and technical personnel to improve the accuracy and performance of the instrument, so that the diagnosis rate can be further improved. (2) Thermal activity runs through the whole process of human life, and the law of thermal activity is the basic law of life activities. So far, there have been no reports on the system and regularity of human thermal activity. This requires us to continuously explore in clinical applications, summarize the physiological laws and pathological laws of human thermal activity, provide more abundant diagnostic experience for clinicians, and lay a solid theory for clinical diagnosis of infrared thermography. basis.
Undoubtedly, medical infrared thermal imaging technology is a high-tech with high market prospects. It shows its infinite charm in many aspects such as tumor warning, pain diagnosis, inflammatory diagnosis, vascular function testing and sub-health monitoring and evaluation. With the gradual improvement of people's living standards and the growing awareness of health, there is a higher demand for early, rapid, accurate, convenient and non-invasive diagnosis. Medical infrared thermal imaging technology will rapidly develop and grow in this market background, and will make an invaluable contribution to the development of human health.
