**10. Treatment verification and delivery**

Portal images by electronic portal imaging device on treatment machines are taken on first 3 days on treatment and then weekly afterwards. These are compared and registered with digitally reconstructed radiography (DRR) from CT simulations to allow offline corrections. For SBRT, cone beam CT by onboard imaging on treatment machine is done daily to allow online correction before delivery of each fraction of treatment.

During treatment period, patients should be reviewed at least once by radiation oncologists for assessment of any acute radiation side effects. Mild chest symptoms like cough or dyspnea are common but concomitant chest infection should be excluded if symptoms worsened. Dysphagia can occur due to esophagitis which usually start at around third week. Adequate analgesics and diet advice should be given to minimize severity and the impact on nutrition or weight loss.
