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Open Access Publications from the University of California

No Tool Left Behind

  • Author(s): Kudva, Aditya
  • Bhatnagar, Shrishti
  • Shah, Anand
  • Strack, Dacoda
  • et al.
No data is associated with this publication.

Background:  Our aim is to design a device that tackles the issue of surgical tools being left behind in a patient's body after an operation. Such objects are referred to as Retained Foreign Objects (RFO).


Unintentionally retained surgically placed foreign bodies have been associated with increased morbidity and mortality, as well as increased costs and medicolegal consequences.


Hence the need to develop a technology that can detect RFO's arises, since there is no room for error. Small pieces of magnets are attached to a surgical sponge (RFO). The magnets will help detect the sponges if they are left behind, by wrapping two mats around the patient securing them using a safety strap.

The tiles on the mats have magnetometers that detect the presence of the sponge in the patient's body. Two readings are taken using the mats. The first one is taken before the operation and the second one, after.


This allows us to measure the change in the earth's magnetic field by comparing the two readings. The data is sent to a smartphone device where the heat maps are generated and compared to pinpoint the location of the sponges.


Faculty Adviser:  Professor G. P. Li, Department of Electrical Engineering and Computer Science              ;

Dr. Michael Klopfer, Cal IT2

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No Tool Left Behind