EARLY LUNG CANCER DETECTION USING COMPUTED TOMOGRAPHY

INTRODUCTION Lung cancer is the leading cause of cancer-related death in United States and worldwide with around 1.3 million death per year. But general prognosis of lung cancer is poor. Overall, 16% of people in the United States diagnosed with lung cancer survive five years after the diagnosis [1]. Late diagnosis is the primary reason for the high mortality. Lung cancer is assigned a stage from I to IV in order of severity. Stage is often advanced at the time of diagnosis. At presentation, 30-40% of cases of non-small cell lung cancer (NSCLC) are stage IV, and 60% of SCLC are stage IV. Higher-stage cancers generally have a worse prognosis than lower-stage cancers [2]. If lung cancer can be detected early, the survival rated can be improved significantly. Existing imaging tests for lung cancer detection include Positron Emission Tomography(PET), Magnetic Resonance Imaging (MRI) and Chest X-Ray. Young et al. have reported that positron emission tomography suffers the problem of low resolution and high false positives. As for MRI, Collette et al.’s research points out that people with metal implants in their body may not be able to have a MRI performed. Because MRI is done using a very strong magnetic field which is possibly move the metal parts in the body [3]. Chest X-Ray has similar problems as PET and it’s not sensitive enough due to Fred et al.’s research. Besides imaging test, lung biopsy is also used. A biopsy is a procedure in which a small tissue sample is removed from the nodule so it can be examined under a microscope. It’s usually invasive and painful. As compared to these traditional tests, Computed Tomography (CT) provides a promising approach in early lung cancer detection. Its high resolution characteristic allows researchers to count the blood vessels within tumors. Although previous research has been conducted to explore efficient methods for early lung cancer detection, little progress is made. This is because early lung cancer is usually symptomless. It often progresses to an incurable stage before being detected. Lung cancer is the uncontrolled growth of abnormal cells in one or both lungs. These abnormal cells do not carry out the functions of normal lung cells and do not develop into healthy lung tissue. Cancer spreads by metastasis, the ability for cancer cells to penetrate into lymphatic and blood vessels, circulate through bloodstream, and then invade and grow in normal tissues elsewhere. Metastasis requires angiogenesis which is the formation of a network of new blood vessels. With angiogenesis, tumor growth proceeds [4]. It is known that tumor growth requires angiogenesis, but it is still unknown that whether there is a relationship between angiogenesis and the malignancy likelihood of pulmonary tumors. Objective and Success Criteria By taking advantage of CT’s high resolution characteristics, my project objective is to count the number of blood vessels within benign and malignant tumors and measure the nodule size (represented by radius, mm), thus determining whether there is a relationship between angiogenesis and the malignancy likelihood of pulmonary tumors. Based on Bagri et al. and Komen et al.’s research, the success criteria is that the malignant pulmonary tumors will exhibit more angiogenesis and will be larger as compared to benign pulmonary tumors[5].