I have a fear of getting lukemia or lung cancer from one chest ct scan which i had one month ago. is it dangerous to have ct scan? can i get cancer ?

Perspective: The risk is too small to measure reliably, and the claims i've seen about diagnostic x-rays causing thousands of cases of cancer yearly look to me to be flawed. You also need to be aware that you're exposed to background radiation constantly that makes up a far greater amount of your exposure. Dna mutates even from quantum fluctuations. If you still can't manage this fear, your doctor can help.

Unlikely: There is some radiation, but very low risk with only one ct.

Risk and Reality: You should not undergo unnecessary CT scans, there is a risk of about 1/10,000. Leukemia is not a real concern. The scan was likely done to assess for a blood clot on the lung. You had a chance of dying if that were true larger than risk of cancer from the CT scan.

No risk: A single chest CT does not pose a risk to you of developing any type of malignancy. Multiple scans over time can increase risk.