Why would a urologist ask for a ct chest scan and bone scan after ct scans of abdomen?

It depends.....: Something on the ct of the abdomen may have lead to a search for metastatic disease. Perhaps a primary malignancy of the kidneys, bladder or prostate. Non-urological disease is also a possibility (such as of the liver). There may also have been evidence of metastatic disease on the abdomen ct and they are now looking for a primary. Bone scan would be done looking for bone metastasis.

Many reasons: If ct of abdomen showed abnormality in kidney or bladder suspicious for cancer. Abnormalities in other organs such as liver, pancreas, bowel can also be seen. Ct exam also demonstrates lower lung field and if something a nodule or pleural effusion was visualized. A bone scan is survey looking for metastatic bone disease. Sometimes bone abnormalities suspicious for tumor can also be detected on ct.