Patients are approached during routine or first-time outpatient clinics of Endocrinology and Surgery, where they are presented to the project, made due explanations and signed the TCLE. This work was conducted under the responsibility of the physician Charbel Pereira Damião, and performed during the hours of operation of the respective attendances without interference in the outpatient routine.

After inclusion in the study, all patients will be evaluated clinically and laboratorially, and will undergo thyroid ultrasonography and thermography. According to the Brazilian guideline, the nodules that have indication are evaluated through Fine Needle Aspiration Puncture. If indicated, patients are referred for surgery.

Clinical evaluation

Clinical evaluation is performed during outpatient visits. The information will be collected from the anamnesis and data of the patient's chart in data collection form: sex, age, color, comorbidities, family history of thyroid disease, history of external radiation or ionizing head and neck in childhood / adolescence .

Laboratory evaluation

The patient's blood is collected by the HUAP routine laboratory, where TSH, free T4 are dosed, which are already part of the routine investigation of thyroid nodules. Therefore, there will be no additional costs to perform them.

Ultrasound evaluation of the thyroid

Patients underwent thyroid Doppler ultrasonography. The examination is performed by the radiology department of the HUAP and is already part of the routine investigation of thyroid nodules. In this examination the ultrasound characteristics of the thyroid nodule are evaluated, such as: echogenicity, contours, presence of halo, microcalifications, presence of suspicious lymph nodes and, at Doppler, the presence of intra and / or extranodal vascularization.

Cytopathological evaluation

Patients are submitted to (PAAF) guided by Ultrasonography of the thyroid nodules according to the Brazilian consensus. The examination is previously scheduled as routine, which is not different from the usual investigation of suspected thyroid nodules. The material for the examination is collected by the radiology department of HUAP and then sent to the pathology department of HUAP for proper analysis.

Thermographic evaluation

The patients recruited, after the outpatient appointments, are referred by the physician Charbel Pereira Damião for the accomplishment of thyroid thermography. The exam is held at HUAP by the graduate students in Computer Science at the UFF Computer Institute, in the presence of the specialist doctor. The exam has an average time of 15 minutes. After adequate patient positioning, its axillary temperature will be verified by means of a clinical thermometer and thermal images will be captured with a FLIR thermographic camera model SC620. Capturing these images does not pose any risk to the patient. The patient will remain in a seated position, with the hyperextending neck resting on a bracket attached to the chair in an air-conditioned room within 0.6 meters of the infrared camera. After the neck is cooled by a ventilator until it reaches the necessary temperature to acquire the images, the patient stays as still as possible for 5 minutes. It is a painless, non-invasive procedure because the patient is not touched or exposed to any kind of radiation. There is no contraindication to its realization, as well as health risks to the patient.

The objective of the thermographic imaging is to capture the temperature distribution over the anterior cervical region where the thyroid is located and its variation with cooling under ventilation in this region. This temperature distribution is captured by a thermal camera (which records them as infrared images) of the brand FLIR model SC620 with 640x480 resolution (= 307200 pixels) in the image and 0.4 degrees Celsius in temperature. Temperature variations in healthy people represent a thermal pattern that is symmetrical in relation to the axis of symmetry situated in the median plane of the human body. A modification of this symmetry on the map at different times of the same subject may be a sign of an abnormality. In this context, 20 images of the neck region where changes in temperature can be recorded in a time interval must be acquired in the same acquisition protocol.