Assess the value of PET/CT in the diagnosis, staging, response evaluation, and relapse monitoring of lung cancer.

Lung cancer is a leading cause of cancer-related mortality worldwide, accounted for 1.80 million deaths in 2020.(1)Egyptian statistics showed that lung cancer in men represents 8.2% of among all cancers of men according to the Egyptian National Cancer Program in 2014 (3).Epidemiological data indicate that the main risk factor for the development of lung cancer is cigarette smoking.(4)Lung cancer is histologically divided into: Non-small-cell lung cancer (NSCLC), which accounts for 85% of cases and Small cell lung cancer (SCLC).(5)Due to absence of screening, most patients with lung cancer are not diagnosed until later stages, when the prognosis is poor.(6)Radiologic manifestations of bronchogenic carcinoma include obstructive pneumonitis or atelectasis, lung nodule or mass, apical mass, cavitated mass, or nodule or mass associated with lymphadenopathy(6)Conventional chest radiography, computed tomography (CT), magnetic resonance imaging, radionuclide scintigraphy, and positron emission tomography (PET) all have been used for NSCLC staging.(7)PET/CT is a well-established radiological modality with high diagnostic accuracy in metastases detection compared to usual CT. Also, it has been reported that up to 10% of patients with bronchogenic carcinoma are found to have metastases on PET/CT that were not detected on CT with subsequent different patients' staging. The high accuracy of PET/CT in tumor staging makes it important for the treatment strategy of either surgical treatment, radiotherapy, or chemotherapy. Also, it becomes essential during the follow-up to detect recurrence. PET/CT shows a higher ability to evaluate the early response to the treatment as chemotherapy by its ability to detect the metabolic response even before the size change.(8)The prognosis of lung tumors depends on early and accurate staging as well as the histopathological type of the primary tumor, with the squamous cell carcinoma type regarded to be of a worse prognosis than that of adenocarcinoma.(9)

Inclusion Criteria:

• Pathologically proven lung cancer patients.

Exclusion Criteria:

• Patients with second malignancy.
• Severely ill patient (patient with disturbed consciousness level, or couldn't lie during the imaging).
• Uncontrolled diabetic patient with blood glucose level more than 200mg\dl.
• Pregnant women.
• Patient age <18 years.

All the pathologically proved lung cancer patient in the oncology department at the sohag oncology Centre.