Minimum Dose Computed Tomography of the Thorax for Follow-up in Patients With Resected Lung Carcinoma

Lung Carcinoma is expected to kill 18,900 men and women in Canada in 2004. This is more than the combined total for the next three common cancers. The most important factor that determines patient survival is the stage of disease at presentation. Surgical resection is the best chance of cure. However, patients who undergo lung resection with curative intent have a significant incidence of a second lung cancer at 2% per year and a recurrence rate of 38% at 5 years. The current follow-up of these patients relies on periodic physical examination and chest radiography(CXR). However, CXR is insensitive in the detection of lung nodules when compared to standard Computed Tomography of the thorax (SDCT). Computed Tomography detects smaller lung nodules than CXR however, the radiation dose from a SDCT is roughly equivalent to 20 CXR examinations. Screening studies using Low Dose CT of the Thorax (LDCT) in subjects at high risk for lung cancer have demonstrated that LDCT detects three times as many nodules as CXR and four times as many primary lung cancers at one-third the dose of SDCT. Phantom and clinical work with LDCT performed at UHN/MSH suggests that a further reduction in radiation dose (Minimum Dose CT -MnDCT) is possible for nodule detection. Minimum dose CT is performed at a dose one sixth of a SDCT.In addition, if MnDCT is confirmed to be a more sensitive nodule detection technique, it could be used to

1. Increase the interval between repeat out-patient assessment and thereby 2. Reduce the overall cost of surveillance and inconvenience to the patient and 3. Free up clinic time for the surgeon to review more patients and reduce waiting lists