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There are errors that can happen during targeting

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for stereotactic core biopsies.

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On pre-fire imaging, I mentioned

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that the needle should point directly at the

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target on both views.

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In this particular situation, the needle is to the right

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of the target on both views.

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If this is symmetric to the right

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or the left of the target, the error is in the x axis

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or horizontal to the floor.

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So we just need to manually move the needle

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to the left along the x axis to align the tip

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of the needle with the target.

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This is a schematic of a post-fire image.

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Remember that on the post-fire image,

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the target should be aligned with the trough.

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In this case, on the post-fire image,

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the calcifications are aligned with the trough,

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but they're too far away.

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So this is an error in the Y axis,

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and all we need to do is move the needle superiorly

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or towards the patient's chest wall on a prones stereotactic

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table in order to be at the appropriate site.

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Here's an example of a post-fire image

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where the needle is still pointing at the calcifications.

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Recall that I mentioned that on the post-fire images,

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the calcifications or the target should align

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with the trough on both views.

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In this case, if the trough is symmetrically proximal

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or distal to the target on both views,

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the error is then in the x axis.

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So here we would just need to advance the needle

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to bring the trough adjacent to the calcifications.

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On both views. There are times

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where errors are compounded.

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Again, as a reminder, on post-fire images,

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the calcifications should align

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with the trough on the post-fire images.

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In this example, one image looks correct,

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but the other doesn't.

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That means that there must be two errors and it's usually X

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and Z that are compounded.

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If we move the needle to the left, uh, along the x axis

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and also then advance the needle, we would bring the uh,

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trough adjacent to the calcifications on both views.