Electrosurgical knife instantly detects cancer during surgery
18 July 2013
The iKnife is a surgical knife that cuts flesh using electrical
current and analyses the vapour to detect characteristic chemicals of
specific cancers using a mass spectrometer.
Invented by Dr Zoltan Takats of Imperial College London, the
iKnife can tell surgeons immediately whether the tissue they are
cutting is cancerous or not and help them determine which tissue to
The iKnife is based on electrosurgery, a technology invented in
the 1920s that is commonly used today. Electrosurgical knives use an
electrical current to rapidly heat tissue, cutting through it while
minimising blood loss. In doing so, they vaporise the tissue,
creating smoke that is normally sucked away by extraction systems.
Dr Takats realised that this smoke would be a rich source of
biological information so connected an electrosurgical knife to a
mass spectrometer. Different types of cell produce thousands of
metabolites in different concentrations, so the profile of chemicals
in a biological sample can reveal information about the state of
The technology was developed at the Imperial Clinical Phenome
Centre, based at St Mary’s Hospital, which was opened last November
and is the first of its type in the world. The Centre has a unique
collection of technologies for rapid molecular analysis in a
hospital setting, aiming to put them at the heart of clinical
decision-making. This includes technologies based on mass
spectrometry deployed in the operating theatre to give surgeons
useful diagnostic information in real-time.
Researchers from Imperial College first used the iKnife to
analyse tissue samples collected from 302 surgery patients,
recording the characteristics of thousands of cancerous and
non-cancerous tissues, including brain, lung, breast, stomach, colon
and liver tumours to create a reference library.
Testing the iKnife in the Clinical Phenome
at St Mary’s Hospital, London
In 91 tests, the tissue type identified by the iKnife matched the
post-operative diagnosis based on traditional methods, but provided
the information in less than three seconds, compared to up to half
an hour using standard laboratory tests.
In cancers involving solid tumours, removal of the cancer in
surgery is generally the best hope for treatment. The surgeon
normally takes out the tumour with a margin of healthy tissue.
However, it is often impossible to tell by sight which tissue is
cancerous. One in five breast cancer patients who have surgery
require a second operation to fully remove the cancer. In cases of
uncertainty, the removed tissue is sent to a lab for examination
while the patient remains under general anaesthetic.
“These results provide compelling evidence that the iKnife can be
applied in a wide range of cancer surgery procedures,” Dr Takats
said. “It provides a result almost instantly, allowing surgeons to
carry out procedures with a level of accuracy that hasn’t been
possible before. We believe it has the potential to reduce tumour
recurrence rates and enable more patients to survive.”
Although the current study focussed on cancer diagnosis, Dr
Takats says the iKnife can identify many other features, such as
tissue with an inadequate blood supply, or types of bacteria present
in the tissue. He has also carried out experiments using it to
distinguish horsemeat from beef.
Professor Jeremy Nicholson, Head of the Department of Surgery and
Cancer at Imperial College London, who co-authored the study, said,
“The iKnife is one manifestation of several advanced chemical
profiling technologies developed in labs our that are contributing
to surgical decision-making and real-time diagnostics. These methods
are part of a new framework of patient journey optimisation that we
are building at Imperial to help doctors diagnose disease, select
the best treatments, and monitor individual patients’ progress as
part our personalised healthcare plan.”
Lord Ara Darzi, Professor of Surgery at Imperial College London,
who also co-authored the study, said: “In cancer surgery, you want
to take out as little healthy tissue as possible, but you have to
ensure that you remove all of the cancer. There is a real need for
technology that can help the surgeon determine which tissue to cut
out and which to leave in. This study shows that the iKnife has the
potential to do this, and the impact on cancer surgery could be
The findings have been published in the journal Science
Translational Medicine . The study was funded by the National
Institute for Health Research (NIHR) Imperial Biomedical Research
Centre, the European Research Council and the Hungarian National
Office for Research and Technology.
1. J. Balog et al. Intraoperative tissue identification
using rapid evaporative ionization mass spectrometry. Sci. Transl.
Med. 5, 194ra93 (2013).