Estimation of tumor characteristics in a breast tissue with known skin surface temperature Koushik Das, Subhash C. Mishra n Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India article info Article history: Received 29 December 2012 Accepted 2 April 2013 Available online 10 April 2013 Keywords: Bioheat transfer Skin surface temperature Tumor characteristics Finite volume method Inverse analysis abstract Presence of a tumor and its characteristics like location, size and properties are estimated. Estimation is based on the measurement of the skin surface temperature of the breast. Consideration is given to a 2-D breast tissue infected with a tumor. Heat transfer in the breast tissue modeled using the Pennes bioheat equation is solved by the finite volume method. Skin surface temperature profile of the breast is characteristic of the tumor location, its size and grade. In the inverse analysis, the objective function is minimized using the genetic algorithm. Exact estimation is obtained if one parameter is estimated at a time. However, the accuracies are acceptable even when blood perfusion rate, location and size are estimated simultaneously. & 2013 Elsevier Ltd. All rights reserved. 1. Introduction Cancer is a life threatening disease. All over the globe, millions of people are in its grasp. No country is spared. Its effect is traumatic. It does not only affect an individual's physical body, but shatters the minds of the patient and his/her near and dear ones. Irrespective of caste, creed and religion, it is growing like an epidemic. Controlling its growth and curing the affected ones, remain a great challenge. As per the latest report of GLOBOCAN, over a period of five years ending in 2008, the number of new cancer cases (incidence) was 12,662,554 and over the same period, the numbers of cancer patients (prevalence) were 28,803,166. Breast cancer is the most common cancer in females. And, over the same 5-year period, the incidence and prevalence of breast cancer were 1,383,155 and 5,189,028 (GLOBOCAN report). Mortality rate varies from cancer to cancer. With breast cancer, it is 33% (GLOBOCAN report). This number is huge. About 3000 females die of breast cancer alone every day. Breast cancer normally starts in the area where the milk is produced i.e., lobules and the milk ducts. Lobular Carcinoma in Situ (LCIS), in its non-invasive form, is a pre-cancerous condition that forms and stays in the lobules. Invasive LCIS is the type of cancer that invades through lobules with a potential to spread to other parts of the body. Ductal Carcinoma in Situ (DCIS), in its non- invasive form, develops in the milk ducts and it does not spread (National Breast Cancer Foundation). If cancer spreads beyond the milk ducts, it is known as ductal carcinoma. Sometimes, cancer in a breast starts in the stromal tissues, fatty and fibrous connective tissues of the breast. Treating any cancer, more so the breast cancer, at an early stage is very important. If left untreated, it has a potential to invade healthy breast tissues and lymph nodes. After it enters the lymph system, there is a likelihood of cancer spreading very easily to other parts of the body (National Breast Cancer Foundation). Depending on the stages of the breast cancer, the size of the cancerous tumor may vary from few centimeters to 5 cm or may be bigger (Fisher et al., 1969). Prognosis and survival rate for any cancer including breast cancer vary depending on its type, stage and geographical location of the patient. In the western countries, the survival rates are high. More than 8 out of 10 women in England diagnosed with breast cancer survive for at least 5 years (World Cancer Report, 2008). This number is lower for the developing countries. The above statistics indicates the volume of research work needed for the diagnosis and the treatment of a breast cancer. Diagnosis is the first and the foremost step in the treatment of any disease. Earlier diagnosis means better chances of cure and survival. This is more so for a cancer. Modern techniques and equipment like computed tomography (CT) scan, magnetic reso- nance imaging (MRI), X-ray mammography, etc., quite efficiently detect malignancies in the body. But, many times a patient has to undergo cumbersome procedures related to these techniques, such as long duration of the diagnostic procedure, side-effects of radiation, high diagnosis cost, etc. (Byrns et al., 2000). Thus, research is needed to develop a simple and less expensive diagnostic procedure without any side effect. The present work focuses on potential application of one such procedure. Considera- tion is given to the estimation of the nature of the tumor in a breast. Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/jtherbio Journal of Thermal Biology 0306-4565/$ - see front matter & 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jtherbio.2013.04.001 n Corresponding author. Tel.: +91 361 2582660; fax: +91 361 2690762. E-mail address: scm_iitg@yahoo.com (S.C. Mishra). Journal of Thermal Biology 38 (2013) 311–317