No two brains are alike, making precision placement of the coils used in TMS therapy tricky. Precise and reliable positioning can make the difference between a successful result and an unsatisfactory one. Conventional coil placement is done using anatomical landmarks like the bridge of the nose, the projecting part of the back of the skull, etc. to align the coil over an intended brain target. This is called the “non-navigated approach." This approach does not need the patient’s MRI.

The “navigated approach,” on the other hand, uses the patient’s MRI, thereby taking into account the individual’s anatomy. From the MRI, one marks out desired brain targets using individual brain landmarks (gyri and sulci). Once marked, the coil can be positioned within a mm of precision over the target. Any subject or operator movement can be immediately compensated for as the brain target is always visible. This approach is similar to the one taken in image-guided stereotaxy when performing brain surgery. Studies have shown unequivocally greater benefit (up to twice as much) when using a navigated approach over the non-navigated one for TMS treatment.