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The optimization of needle electrode number and placement for irreversible electroporation of hepatocellular carcinoma.

Adeyanju OO, Al-Angari HM, Sahakian AV - Radiol Oncol (2012)

Bottom Line: We also found the distance between electrodes was far more important in influencing the outcome measures when compared with the depth of electrode insertion.Overall, the distribution of electric field is highly dependent upon the electrode configuration, but the optimal configuration can be determined using numerical modeling.Our findings can help guide the clinical application of IRE as well as the selection of the best optimization algorithm to use in finding the optimal electrode configuration.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Irreversible electroporation (IRE) is a novel ablation tool that uses brief high-voltage pulses to treat cancer. The efficacy of the therapy depends upon the distribution of the electric field, which in turn depends upon the configuration of electrodes used.

Methods: We sought to optimize the electrode configuration in terms of the distance between electrodes, the depth of electrode insertion, and the number of electrodes. We employed a 3D Finite Element Model and systematically varied the distance between the electrodes and the depth of electrode insertion, monitoring the lowest voltage sufficient to ablate the tumor, V(IRE). We also measured the amount of normal (non-cancerous) tissue ablated. Measurements were performed for two electrodes, three electrodes, and four electrodes. The optimal electrode configuration was determined to be the one with the lowest V(IRE), as that minimized damage to normal tissue.

Results: The optimal electrode configuration to ablate a 2.5 cm spheroidal tumor used two electrodes with a distance of 2 cm between the electrodes and a depth of insertion of 1 cm below the halfway point in the spherical tumor, as measured from the bottom of the electrode. This produced a V(IRE) of 3700 V. We found that it was generally best to have a small distance between the electrodes and for the center of the electrodes to be inserted at a depth equal to or deeper than the center of the tumor. We also found the distance between electrodes was far more important in influencing the outcome measures when compared with the depth of electrode insertion.

Conclusions: Overall, the distribution of electric field is highly dependent upon the electrode configuration, but the optimal configuration can be determined using numerical modeling. Our findings can help guide the clinical application of IRE as well as the selection of the best optimization algorithm to use in finding the optimal electrode configuration.

No MeSH data available.


Related in: MedlinePlus

A–C. Graphical depiction of VIRE values upon distance at several depths. There appears to be a parabolic minima at 2 cm distance between the electrodes for the two electrode set, whereas the VIRE values for both three and four electrodes decrease linearly with the distance between the electrodes. D–F Graphical depiction of the dependence of the VANT values upon distance at several depths. The VANT values decrease with distance for all electrode setups. Two electrodes overall have the lowest VANT values, followed by four electrodes and then three electrodes.
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f2-rado-46-02-126: A–C. Graphical depiction of VIRE values upon distance at several depths. There appears to be a parabolic minima at 2 cm distance between the electrodes for the two electrode set, whereas the VIRE values for both three and four electrodes decrease linearly with the distance between the electrodes. D–F Graphical depiction of the dependence of the VANT values upon distance at several depths. The VANT values decrease with distance for all electrode setups. Two electrodes overall have the lowest VANT values, followed by four electrodes and then three electrodes.

Mentions: The VIRE results for two, three, and four electrodes are graphically depicted in Figure 2 A–C. The highest VIRE values consistently occur at the largest distances for all three sets of electrodes. The two electrode data show a parabolic minimum at a distance of 2 cm. We can observe two regions from the results in Figure 2A, the first where the electrodes are placed inside the tumor and the second where the electrodes are outside the tumor. The two-electrode data show a drop in the voltage as the distance increases from 1 cm, before it rises again near the tumor-tissue boarder at a distance of 2.5 cm. This behavior is observed for all electrode depths. The lowest VIRE values occur at depths of 1 cm and 1.25 cm, which correspond to the center of the electrode overlapping with the center of the tumor. The higher VIRE values generally occur at a depth of 1.5 cm and then 0.5 cm, indicating the highest VIRE values are at the shallowest depth of insertion, and the deepest insertions (lower overlap) produce lower VIRE values.


The optimization of needle electrode number and placement for irreversible electroporation of hepatocellular carcinoma.

Adeyanju OO, Al-Angari HM, Sahakian AV - Radiol Oncol (2012)

A–C. Graphical depiction of VIRE values upon distance at several depths. There appears to be a parabolic minima at 2 cm distance between the electrodes for the two electrode set, whereas the VIRE values for both three and four electrodes decrease linearly with the distance between the electrodes. D–F Graphical depiction of the dependence of the VANT values upon distance at several depths. The VANT values decrease with distance for all electrode setups. Two electrodes overall have the lowest VANT values, followed by four electrodes and then three electrodes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472940&req=5

f2-rado-46-02-126: A–C. Graphical depiction of VIRE values upon distance at several depths. There appears to be a parabolic minima at 2 cm distance between the electrodes for the two electrode set, whereas the VIRE values for both three and four electrodes decrease linearly with the distance between the electrodes. D–F Graphical depiction of the dependence of the VANT values upon distance at several depths. The VANT values decrease with distance for all electrode setups. Two electrodes overall have the lowest VANT values, followed by four electrodes and then three electrodes.
Mentions: The VIRE results for two, three, and four electrodes are graphically depicted in Figure 2 A–C. The highest VIRE values consistently occur at the largest distances for all three sets of electrodes. The two electrode data show a parabolic minimum at a distance of 2 cm. We can observe two regions from the results in Figure 2A, the first where the electrodes are placed inside the tumor and the second where the electrodes are outside the tumor. The two-electrode data show a drop in the voltage as the distance increases from 1 cm, before it rises again near the tumor-tissue boarder at a distance of 2.5 cm. This behavior is observed for all electrode depths. The lowest VIRE values occur at depths of 1 cm and 1.25 cm, which correspond to the center of the electrode overlapping with the center of the tumor. The higher VIRE values generally occur at a depth of 1.5 cm and then 0.5 cm, indicating the highest VIRE values are at the shallowest depth of insertion, and the deepest insertions (lower overlap) produce lower VIRE values.

Bottom Line: We also found the distance between electrodes was far more important in influencing the outcome measures when compared with the depth of electrode insertion.Overall, the distribution of electric field is highly dependent upon the electrode configuration, but the optimal configuration can be determined using numerical modeling.Our findings can help guide the clinical application of IRE as well as the selection of the best optimization algorithm to use in finding the optimal electrode configuration.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Irreversible electroporation (IRE) is a novel ablation tool that uses brief high-voltage pulses to treat cancer. The efficacy of the therapy depends upon the distribution of the electric field, which in turn depends upon the configuration of electrodes used.

Methods: We sought to optimize the electrode configuration in terms of the distance between electrodes, the depth of electrode insertion, and the number of electrodes. We employed a 3D Finite Element Model and systematically varied the distance between the electrodes and the depth of electrode insertion, monitoring the lowest voltage sufficient to ablate the tumor, V(IRE). We also measured the amount of normal (non-cancerous) tissue ablated. Measurements were performed for two electrodes, three electrodes, and four electrodes. The optimal electrode configuration was determined to be the one with the lowest V(IRE), as that minimized damage to normal tissue.

Results: The optimal electrode configuration to ablate a 2.5 cm spheroidal tumor used two electrodes with a distance of 2 cm between the electrodes and a depth of insertion of 1 cm below the halfway point in the spherical tumor, as measured from the bottom of the electrode. This produced a V(IRE) of 3700 V. We found that it was generally best to have a small distance between the electrodes and for the center of the electrodes to be inserted at a depth equal to or deeper than the center of the tumor. We also found the distance between electrodes was far more important in influencing the outcome measures when compared with the depth of electrode insertion.

Conclusions: Overall, the distribution of electric field is highly dependent upon the electrode configuration, but the optimal configuration can be determined using numerical modeling. Our findings can help guide the clinical application of IRE as well as the selection of the best optimization algorithm to use in finding the optimal electrode configuration.

No MeSH data available.


Related in: MedlinePlus