In principle, tomographic imaging of breast implants provides the information needed to compute implant volume. We have investigated the reliability of this measurement as a means of diagnosing the loss of gel from the implant. We find that measurement errors, postimplantation changes of the implant, uncertainties in the patients' records, and lack of knowledge of the implant temperature in the body can lead to significant discrepancies, making this measurement unreliable as a diagnostic tool.