Abstract
Breast thermography is an emerging adjunct tool to mammography in early breast cancer detection due to its non-invasiveness and safety. Steady-state infrared imaging proves promising in this field as it is not affected by tissue density. The main aim of the present study is to develop a computational thermal model of breast cancer using real breast surface geometry and internal tumor specification. The model depicting the thermal profile of the subject's aggressive ductal carcinoma is calibrated by variation of blood perfusion and metabolic heat generation rate. The subject's IR image is used for validation of the simulated temperature profile. The thermal breast model presented here may prove useful in monitoring the response of tumor post-chemotherapy for female subjects with similar breast cancer characteristics.
TopIntroduction
One of the most common cancers among women is breast cancer (BC). In 2018 BC had the second highest rate of mortality among women (“Breast Cancer Facts and Figures 2019-2020,” n.d.)(“Breast cancer statistics in India,” n.d.).Infrared Imaging (IRI) or breast thermography is a comparatively inexpensive diagnostic technique as compared to mammography and has the potential to indicate thermal abnormalities indicating BC. This enables IRI to be used as an adjunct tool to mammography. In IR imaging, an IR camera captures the infrared radiations emitted by a human body and records the variation of surface temperature of that body. Cancer causes patho-physiological changes within the breast including metabolic and vascular changes. The intensity of the radiation emitted is dependent on the temperature of the body, given by Planck’s Radiation Law:
(1) Where I is the intensity of radiation, 𝜆 is the wavelength, T is the absolute temperature,
h is the Planck’s constant,
c is the speed of light in vacuum and
k is the Boltzmann constant. For human body, most of the radiation is within IR spectrum in the bands between 2 and 20μm. The main purpose of using IR thermography is that it doesn’t cause exposure to ionizing radiations and is useful for dense breast tissue. In the present study, thermal simulation of aggressive tumor based on variable blood perfusion rate and metabolic heat generation rate in a realistic three dimensional breast model, is performed. The resulting surface temperature profile is matched with pre-processed and segmented IR images of the subject. The main objective of the present study is to compute the thermal characteristics of aggressive grade 2 breast cancer by calibrating the bioheat model with real clinical data.
Key Terms in this Chapter
Ductal Carcinoma: Presence of abnormal cells inside a milk-duct in the breast.
Contra-Lateral: Denoting the side of the body opposite to that on which a particular condition occurs.
Thermal Conductivity: Quantity of heat that passes per unit time through a unit area of a particular thickness, where opposite faces differs in temperature by 1 K.
Biopsy: The removal of some tissues from somebody’s body in order to find out about a disease that a person may have.
Pre-Processing: Operations on images at the lowest level of abstraction in order to improve the image data.
Adjunct: Something that is joined or added to another thing but is not an essential part of it.
Blood Perfusion Rate: Volume of blood per unit time per unit tissue mass.
Continuum: Gradual transitions from condition to another without abrupt change.