The advantage of this technique is that there is no need to place the localisation mark on the day of surgery. Conventional wires however, need to be placed AND removed on the day of surgery. The wire end comes through the breast skin and can cause discomfort; furthermore if it is pushed/pulled, it can become misplaced. To avoid these problems surgery must take place soon after insertion, then removed again afterwards. A Radiologist is needed for each procedure, which can be difficult to organise. The 'seed' can be inserted/removed weeks or months before surgery, so lessening the stress incurred on that day.