Is It Serious To Warrant Thallium Tmt?

my ecg came with remark of non specific t flattening /inversion, advised tmt and echo, result of echo EF 64%, no RWMA and result of TMT was mild TR, have been advised thallium tmt

my bp is normal 135/82, cholestral 174 (with medication atorva 20 mg), exercise moderately brisk walk everday 40 mins, weights twice a week

is it serious to warrant thallium tmt