[Rich66]

Doctors tout NanoKnife for easy tumor removal

February 5, 2010 By Fred Tasker A University of Miami doctor recently removed two cancerous tumors from a patient's liver using only three needle-like probes, a computer and a powerful burst of electricity.

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"We're still in the early stages of using it," he says. "It's good for tumors less than five centimeters; for really big tumors it's less good. My guess is it will be very effective in selective patients."

Hays, the Arkansas radiologist, agrees that, since the NanoKnife creates no heat or subfreezing temperatures, it can be used in some patients who can't undergo radiofrequency ablation and cryoablation.

• OCTOBER 5, 2010

Some Doctors Question New Cancer Treatment

NanoKnife Used in Select Hospitals Shows Promising Results, but Hasn't Received 'Gold Standard' Test, Maker Says

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AdvaMed, the medical-device industry association, says products approved through FDA shortcuts "have an extremely good overall record" of safety, and that any regulatory changes "should be directed toward device types where there have been demonstrated issues."
The NanoKnife was approved in 2008 because it was shown capable of destroying tissue similar to other existing devices that are used in heart surgery. But the NanoKnife, which isn't really a knife, was put to work treating cancer, excising malignant tumors that are near arteries, airways or other vulnerable tissues and thus difficult to remove.
The device, about the size of a small refrigerator, is connected to disposable electrode needles that are inserted into the tumor. Powerful electrical jolts fire from one needle to the other, creating microscopic holes in the cell membranes of cancer cells that are meant to destroy the tumor.
Medicare doesn't specifically pay for use of the NanoKnife, though hospitals and doctors get reimbursement under more general medical-treatment billing codes. Some private insurers, including Arkansas BlueCross BlueShield, decline to cover its use because of the lack of "scientific evidence of effectiveness in improving health outcomes."
Gary Onik, a retired interventional radiologist and the NanoKnife's inventor, says he has treated about 30 patients with the device and the result "was phenomenal." All but two of the patients were cancer-free two years after the procedure, he says.

Technol Cancer Res Treat. 2011 Aug;10(4):347-60.
The improvement of irreversible electroporation therapy using saline-irrigated electrodes: a theoretical study.

Adeyanju OO, Al-Angari HM, Sahakian AV.
Source

Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA. lolu@fsm.northwestern.edu

Abstract

Irreversible electroporation (IRE) is a novel therapy used to ablate tumors with high-field electric pulses applied in short durations. It is important to reduce the generation of heat in IRE to avoid the harmful effects of thermal damage. The objective of this simulation study was to examine the effects of saline irrigation in the reduction of heat upon electrodes used in IRE treatment of hepatocellular carcinoma. We used a two dimensional Finite Element Model of a tumor in a liver with electrodes placed at the center of the tumor. We simulated a typical electroporation protocol with varying thicknesses and conductivities of the saline layer, and we observed the maximum temperature and the distribution of the electric field and temperature in the tissue. Our results showed that the maximum temperature in the tissue decreases with the use of saline, but the surface area of the tumor that could potentially be thermally damaged may increase with the thickness and conductivity of the saline. With the use of saline, one can achieve upwards of a 17% reduction of the maximum temperature at the electrodes. Also, the distribution of temperature and the electric field becomes more homogenous between the electrodes as the conductivity of the saline layer increases for all thicknesses of saline. We conclude that irrigating electrodes with saline may be an effective measure to enhance the efficacy of irreversible electroporation by reducing the maximum temperature at the electrodes and also improving the extent and distribution of the electric field in the tissue. However, the properties of the saline should be adjusted so as to limit the increase of thermal damage propagated in the tissue.

PMID:

21728392

[PubMed - in process]