The treatment of an adenoma depends on the chance that it may be a cancer and whether or not it is raising hormone levels. When an adrenal tumor is found accidentally, tests are often done to see if it is making hormones. If it is, surgery is often recommended. Otherwise, surgery may only be recommended if it is likely to be a cancer. Small tumors are less likely to be cancer, and are often watched but not treated right away. The CT (or MRI) scan can be repeated in 6 to 24 months to see if the tumor has grown. If it has, it may need to be removed. If it hasn't grown, hormone levels will be watched over the next few years. If the tumor stays small and doesn't make any hormones, it might not need to be treated at all.
Catecholamines are produced in chromaffin cells in the medulla of the adrenal gland, from tyrosine , a non-essential amino acid derived from food or produced from phenylalanine in the liver. The enzyme tyrosine hydroxylase converts tyrosine to L-DOPA in the first step of catecholamine synthesis. L-DOPA is then converted to dopamine before it can be turned into noradrenaline. In the cytosol , noradrenaline is converted to epinephrine by the enzyme phenylethanolamine N-methyltransferase (PNMT) and stored in granules. Glucocorticoids produced in the adrenal cortex stimulate the synthesis of catecholamines by increasing the levels of tyrosine hydroxylase and PNMT.  
A chemical called I-123-MIBG (meta-iodobenzylguanidine) may be used to show up the site of a phaeochromocytoma on a scan. I-123-MIBG contains mildly radioactive iodine and is taken up by adrenal cells. The scan takes place over two consecutive days in the nuclear medicine department. On the first day, you will go to the department twice. In the morning you will be given an injection in the arm. You can then stay in, or leave, the hospital. You will go back to the department in the afternoon to have a scan with a gamma camera, which lasts for about an hour. The next morning you will have more pictures taken for about one and a quarter hours. At this point you may be given another injection.