Several methods for a breast biopsy now exist. The most appropriate method of biopsy for a patient depends upon a variety of factors, including the size, location, appearance and characteristics of the abnormality. A self-organizing map (SOM) or self-organizing feature map (SOFM) is a type of artificial neural network that is trained using unsupervised learning to produce a low-dimensional (typically two-dimensional), discretized representation of the input space of the training samples, called a map. Self-organizing maps are different from other artificial neural networks in the sense that they use a neighborhood function to preserve the topological properties of the input space. A biopsy is a medical test commonly performed by a surgeon or an interventional radiologist involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. This article is about the human breast. For other animals, see Udder and Mammary gland. ‘Boobs’ redirects here. For other uses, see Boob (disambiguation). For other uses, see Breast (disambiguation) Breast File:Closeup of female breast. Diagnostic sonography (ultrasonography) is an ultrasound-based diagnostic imaging technique used for visualizing subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions. Obstetric sonography is commonly used during pregnancy and is widely recognized by the public. In physics, the term ‘ultrasound’ applies to all sound waves with a frequency above the audible range of human hearing, about 20 kHz. A lesion is any abnormality in the tissue of an organism (in layman’s terms, ‘damage’), usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury. Breast cancer is a type of cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas, those originating from lobules are known as lobular carcinomas. Breast cancer is a disease of humans and other mammals, while the overwhelming majority of cases in humans are women, men can sometimes also develop breast cancer. Redox (reduction-oxidation) reactions include all chemical reactions in which atoms have their oxidation state changed. This can be either a simple redox process, such as the oxidation of carbon to yield carbon dioxide (CO2) or the reduction of carbon by hydrogen to yield methane (CH4), or a complex process such as the oxidation of glucose (C6H12O6) in the human body through a series of complex electron transfer processes. Source.