How can i convince my md to give me a chest ct? i'm petrified i already have cancer somewhere from smoking.

Not sure: Not sure how you can convince your doctor but the recommendations for screening ct for lung cancer are after you've smoked 1 pack per day for 30 years or the equivalent (ie 2 packs/day for 15 years). If you fall into this category, it may be a convincing argument.

Diagnostic testing: Chest cts are not screening tests for cancer. It is a diagnostic test for symptoms or other high risk patients. Discuss with your primary care doctor your concerns and see if there is a definitive indication for a ct.

Weigh benefits: Many physicians are now screening smokers with chest ct's from time to time, excising the little cancers that can only be seen on ct. This has brought about a considerable increase in the number of lung cancers found and "cured" but has had very little impact on total deaths. But if you are "petrified" your emotional state alone might justify one of these pop screens. Good luck.