1. Default ○ Clear lung ○ Visible rib ○ Normal heart + diaphragm contours ○ Trachea midline does not have any signs of masses 2. Tuberculosis ○ Aortic enlargement could be seen i. Due to chronic inflammation ii. Cardiovascular strain ○ Calcification - granulomatous infection , lesions ○ Scarring visible ○ Chronic TB i. Or could be prior pleuritis ○ Lesion could mean inactive or active TB i. Could be seen in upper lobe fibrosis 3. Lung tumor ○ Nodule/Mass i. Rounded opacities = primary/secondary tumor ○ Lung opacity i. Hemorrhage ii. Infection iii. Can indicate collapse ○ Can be seen as solitary pulmonary nodules when metastasized ○ Silhouette signs i. Normal border cannot be seen near heart and aorta ii. Localizing information of tumor ○ Not recommended for routine treatment (change in mass size) in some cases 4. Pneumonia (bottom left + bottom right) ○ Bilateral lung opacity i. Alveolar consolidation - bacterial pneumonia ○ Asymmetrical distribution i. Affects in 1+ lobes ○ Air bronchograms are present ○ Shows white patches with fluid filled alveoli insead of air Limited role in screening ● LDCt (low dose CT) ○ Only effective for high risk population ■ Used to target lung cancer or age related cancer therapy ■ ex) individuals with old age with smoking history ● age) 50-80 ● Current smoker, quit within 15 year ● Asymptomatic or is healthy to undergo treatment when tumor is found during screening ● Need decision making before screening ○ Patients and guardians must know about benefits and harm in followup ○ Lower radiation doses compared to standard scan ■ Reduce tube current (mA) + peak voltage (kVp) ■ Quick table speed ■ Reconstruction