Spot on Lung xray

[cinders166]

last week I  had an xray of my lungs because I was going in for a yearly check up, and thought I should get a chest xray since I've been doing alot of coughing up junk, and have trouble breathing sometimes. By this breathing problem, I feel like someone is standing on my chest, (not pain, just heaviness), and at the same time someone is covering my mouth. I know this sounds weird but it's the only way I can explain it . My gut instinct (which is very good)  tells me something in my chest just isn't right.
Yes, I've been a smoker for 37 years.
The chest xray showed I had a spot on my upper right lobe of my right lung. A spiral cat scan was set up for the next day@ the hospital. When the doctor's nurse called me with the results of the spiral cat scan, she said it was negative. I asked what exactly that meant, and she said they found no spot.
My question is.... how does a spot show up on the xray, but not on a more thorough test like the cat scan. I still feel really uneasy about the results. My doctor told me to get another xray in 3 months, and another spiral cat scan in 6 months. I'm worried about waiting that long. Can someone please answer this question? Thank you

[cinders166]

Thanks so much for your quick response to my lung spot question. This is a truly valuable  website service that you do for people, and I'm sure glad your available. I hope you have a great evening, and again thank you so much, you made it so much more clear for me. Bless you.
Cinders166

[HeinrikMD]

Hi,

The chest Xray shows details that are overlapped. The heart is overlapped with the backbone, the ribs overlap on the lungs and on the other ribs. The CT scan takes images that are slices. My best description here is the magician’s trick of slicing the volunteer in half across the waist. Hence, if the slice is through the chest, the ribs would form a ring and the lung would be viewed without overlaps. The CT may miss small spots if the spot is in the interval between slices. The size of such a spot would usually be below the threshold capacity of  the X Ray.
Surveillance as a strategy has been done for a large number of patients, and algorithms have been developed. The strategy balances the risks of invasive diagnostic procedures with that of missing a potentially curable disease at an early stage. Stay positive.