## 4 Thermographic Techniques for Breast Cancer Detection
### Steady-State Thermography  
To create a data bank of normal breast thermograms, [PERSON] et al. [48] examined 50 healthy and normal mentrauting women by means of steady-state thermography to investigate the cyclic variation of temperature and vascularization of their normal breast thermograms. In fact, establishing the surface isotherm pattern of the healthy breasts and the normal range of cyclic variations of temperature over time is paramount to identifying the abnormal infrared images of diseased breasts. The examination was performed in a controlled room maintained at a temperature of 22 \({}^{\circ}\)C and a relative humidity between 60 and 70%. Thermal images were recorded using a contact thermogram system (encapsulated liquid crystal SINOTEST MSP8) with various thermographic plates after the subject rested for 15-20 min for acclimatization. The authors also established the best period for the thermographic examination of a female subject in relation to the menstrual cycle. A thermographic analysis of normal breasts was also performed by [PERSON] et al. [49]. Their study involved 35 healthy female patients whose breasts were imaged using steady-state thermography after a break of 5-10 min for acclimatization in a room that was maintained between 21 \({}^{\circ}\)C and 25 \({}^{\circ}\)C. However, during the examination, the temperature changes were ensured to be within 1 \({}^{\circ}\)C. Moreover, thermal images were acquired in the anteroposterior, left and right lateral, and left and right oblique views with the IR \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Study** & \begin{tabular}{c} **Thermal** \\ **Imaging** \\ **Technique** \\ \end{tabular} & \begin{tabular}{c} **Sample Size and** \\ **Lesion Type** \\ \end{tabular} & \begin{tabular}{c} **Camera** \\ **Specifications** \\ \end{tabular} & \begin{tabular}{c} **Cooling/Heating** \\ **Methods/** \\ **Accimatization** \\ **Information** \\ \end{tabular} & **Findings/Results** \\ \hline \begin{tabular}{c} [PERSON]- \\ rine and [PERSON] [44] \\ \end{tabular} & Lock-in Thermography. & \(\cdots\) & \begin{tabular}{c} IR camera and \\ temperature- \\ modulated air flow \\ \end{tabular} & \begin{tabular}{c} Temperature- \\ modulated air flow \\ synchronized with \\ the camera. \\ \end{tabular} & \begin{tabular}{c} Temperature- \\ modulated air flow \\ \end{tabular} & \begin{tabular}{c} Used lock-in \\ thermography for \\ dermatological \\ applications, \\ reported results for \\ benign skin lesions. \\ \end{tabular} \\ \hline \begin{tabular}{c} [PERSON] et al. [45] \\ \end{tabular} & Thermal Wave Imaging & \(\cdots\) & \begin{tabular}{c} IR camera and \\ controlled heating. \\ \end{tabular} & \
\begin{tabular}{c} Controlled heating of \\ the skin surface. \\ \end{tabular} &
\begin{tabular}{c} Theoretical feasibility \\ of FMVI for \\ detection and \\ differentiation of \\ melanoma stages. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._camera placed 1 m away from the patient. In particular, the HYIR I-1206 medical thermal imager, with an image resolution of 384 \(\times\) 288 pixels, a temperature sensitivity of 0.08 \({}^{\circ}\)C, and operating in the spectral range of 8-14 \(\mu\)m, was employed. The authors found evidence that the temperature distribution of healthy breasts was symmetrical and that the mean temperatures of both breasts were almost equal. However, slight differences in the temperature were reported between the upper left and right quadrants and between the upper and lower quadrants. [PERSON] et al. [50] selected a group of 276 women who were scheduled to undergo an excisional biopsy based on mammograms or ultrasounds to be examined using steady-state thermography the day before surgery.