Which one of the following techniques is safest for the detection...

Magnetic Resonance Imaging (MRI) is a non-invasive technique, which uses strong magnetic field and provides information about chemistry, metabolic and biochemical data of tissue without time consuming chemical analysis. It is the safest technique for the detection of cancer since it does not utilize radiations and therefore, does not cause any side effect. Histopathological study is not safe as it is invasive technique while radiography and Computed Tomography (CT) use harmful $\mathrm{X}$-rays.