MIBG test advised. As malignant?

My current treating doctor suspected pheochromocytoma since I have been having frequent spells of high blood pressure. The first time it was detected was 4 years back. The blood pressure keeps fluctuating and gets intense during stressful situations. I was also diagnosed with anxiety disorder 4 years back accompanied with chronic panic attacks which didn't show resistance to the anti-anxiety and antidepressants. I also developed a depressive episode 1 year back and still on antidepressants and anti-anxiety medications. Got my plasma test and 24hr urine test done and report enclosed. Today my doctor has recommended MIBG test for further imaging and diagnosis. Would like to know more about MIBG test and does the report suggests that it could be pheochromocytoma? Also are there a possibility of pheochromocytoma tumor being detected as malignant?