## 1 Introduction  
Lung nodules are tiny clusters of cells that are highly frequent in the lungs. The majority of lung nodules are scar tissue from previous lung infections. Lung nodules seldom cause symptoms. They are frequently discovered by chance on a chest X-ray or CT scan performed for another purpose. Some lung nodules are malignant, while others are not. The majority of nodules are harmless. People may seek medical attention if a nodule grows fast or continues for an extended period. Small, non-cancerous lung nodules usually have little effect on your quality of life. According to a 2020 study, persons with solitary malignant nodules had a 3-year overall survival rate of 93.6% and a 5-year overall survival rate of 89.8% [1]. Shortness of breath, back discomfort, weight loss, weakness, and weariness are all symptoms of lung nodules. When a patient exhibits signs of a respiratory ailment or infection, a doctor will often order a chest X-ray or a CT scan. A CT scan provides a more comprehensive image and can detect nodules as tiny as 1 cm. The optimal therapy for a lung nodule typically relies on whether it contains characteristics that indicate cancer risk. Lung cancer is the leading cause of cancer-related mortality in the United States and the third most prevalent cause of death overall [2]. Cancer comprises a group of illnesses distinguished from one another by the uncontrolled development of aberrant cells. Cancer is a catchall term for a group of diseases that have the potential to invade other sections of the body or spread after they have established a foothold in one area. After receiving a cancer diagnosis, a patient's prognosis may be influenced by various circumstances, including treatment options. It is crucial to note that while there is a strong correlation between the advancement of cancer to later stages (stages 3-4) and a poorer prognosis, this association is not always cut and dried. It is far more difficult to precisely diagnose and treat a specific patient because there are more than a hundred forms of cancer [3; 4; 5]. The degree of difficulty varies depending on the kind of sickness and the patient's current state of health. It is of the utmost importance to provide the medical community with unique shortcuts to enable a rapid diagnosis of the specific kind of cancer and the stage at which it was discovered. Lung cancer is a danger to the general public's health on a global scale. With over 884,000 occurrences yearly, lung cancer is the third most prevalent cancer in developed nations. Breast and colon cancer are the two most pervasive kinds [6]. In an attempt to lower the mortality rates brought on by lung cancer, the governments of several countries have made the construction of early detection and screening programs for the disease a top priority. The National Lung Screening estimates that low-dose computerized tomography (CT) screening might lower the mortality rate from lung cancer by 20%. Radiologists risk missing specific tiny lung cancer nodules by looking at a large volume of medical pictures when evaluating patients utilizing LDCT. Radiologists may identify patients more quickly and accurately using computer-aided detection systems (CADs), which may offer potential nodules with particular placements. In the United States of America, there will be around 222,500 new cases of cancer diagnosed in 2020. Early detection of uncontrolled cell growth is essential since it may considerably increase a patient's chances of surviving the illness because unchecked cell proliferation is the primary cause of lung cancer. Lung cancer patients can now start treatment sooner because of the advent of CT imaging, which has significantly increased the likelihood of achieving an early diagnosis. The focused opacity and size range of three to thirty millimeters of a nodule may be utilized to identify it. The development of computer tomography has led to the discovery of many lung nodules that vary in kind and size [7].