I hope you can identify some ways to decrease your anxiety re this test. I cannot tell you if one test is better than another but your Dr. has chosen this test so perhaps you want to talk to him re why this test over the treadmill.
Most people that have the scan also do the physical exercise as well.
I have read that Myoview stress test with a scan before and after the exercise portion is more accurate than the standard exercise test. However whenever we read something you can bet there is another study somewhere that will contradict what you read.
If the scan is correct 80% of the time there must be a follow-up of some sort that the cardiologists use if they suspect the tests results are incorrect.
Be sure to write all your questions down so you can ask your Dr. as he is truly the one with the best answers as well as he ordered the test so he should be explaining why he chose this test and he knows what your issues are that brought you in to see him in the first place.
I do know how hard it is to remain calm but remember we all have anxiety so do what you have done in the past to control your worries and just make it through the test.