Bio‐Medical Precision Engineering LabIchiro Sakuma, Estuko Kobayshi, Takehiro AndoSchool of Engineering, The University of Tokyo

• Computer Aided Surgery• Robotics for CAS• Electrophysiology of Arrhythmia

real time segmentation

5-ALA2.8μmicro-Laser

log

real time segmentation

5-ALA2.8μmicro-Laser

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2.8μmicro-Laser

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• 5‐Aminolevulinic Acid (5‐ALA) and Protoporphyrin IX (PpIX)

• 5‐ALA accumulates on tumors, and metabolizes to PpIX in malignant glioma.

• PpIX is a fluorescent substance; emits red fluorescence when it is excited by blue light.

５－ALA for intraoperative identification of malignant brain tumor

tumorbrain surface

5-ALA leads to intracellular accumulation of fluorescent prophyrins PpIX in malignant gliomas

PpIX

5-ALA

(Friesen et al, 2002)

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System configuration

Medical Image Analysis 16(3): 1361‐8415.

Laser ablation of porcine brain stained with 5‐ALA(Noguchi M., 2006) 

Agar gel with intra‐lipid and Pp9(10[μg/ml])

• NEDO(New Energy and Industrial Technology Development Organization) “Intelligent Surgical Instrument Project”Sub‐project: Intelligent surgical instrument for minimally invasive thoracic surgery

• Periodic research meetings among researchers in clinical medicine, engineering, and industries

• Design modification through tests using prototypes in repeated workshops

http://www.nedo.go.jp/news/press/AA5_100145.htmlhttp://www.youtube.com/watch?v=aKdE8C8KcJI

Movie

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• Spiral is characterized by progressively increasing radius of curvature toward the center.

• Conduction velocity slows down toward the center because of progressive decrease of the source/sink ratio and eventually becomes zero.

• At the center, various phases of excitation meet and formulate singular point. The wavefront meets its own refractory tail and rotation persists around this pivot point.

Ventricular Tachycardia (VT), Ventricular fibrillation （VF)• Major cause of sudden cardiac death

• Reentrant excitation is one of the major cause of VT and VF

Optical Mapping of Cardiac Excitations

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Lig

ht I

nten

sity

Time

BackgroundComponent(F)

ΔF/F < 10%

Action PotentialAmplitude( F)Δ

Wavelength

Ligh

t stre

ngth Excitation

light

Resting

500 nm 600 nm

Excited

△F

Use of voltage sensitive dye: Di‐4‐ANEPPSSuppression of contraction by 2,3‐butandione monoxime(BDM)

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Application of visual feedback to eletctrical stimulation

High Speed

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