Author: Sakuma, I. Presentation for the Biomedical & Mechatronics Workshop Forum UTokyo USP, 2013

1. Bio‐Medical Precision Engineering Lab
Ichiro Sakuma, Estuko Kobayshi, Takehiro Ando
School of Engineering, The University of Tokyo
• Computer Aided Surgery
• Robotics for CAS
• Electrophysiology of Arrhythmia
real time segmentation
log
5-ALA
2.8μmicro-Laser

2. ５－ALA for intraoperative identification of malignant
brain tumor
• 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.
tumor
brain surface
5-ALA
PpIX
(Friesen et al, 2002)
5-ALA leads to intracellular
accumulation of fluorescent
prophyrins PpIX in malignant
gliomas

3. System configuration
Medical Image Analysis 16(3): 1361‐8415.
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4. Laser ablation of porcine brain stained with 5‐ALA
(Noguchi M., 2006)
Agar gel with intra‐lipid
and Pp9(10[μg/ml])

5. • 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.html
http://www.youtube.com/watch?v=aKdE8C8KcJI

6. Movie

7. Ventricular Tachycardia (VT), Ventricular fibrillation （VF)
• Major cause of sudden cardiac death
• Reentrant excitation is one of the major cause of VT and VF
• 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.
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8. Excitation
light
Excited
Resting
△F
500 nm
600
nm
Wave
length
Light Intensity
Light strength
Optical Mapping of Cardiac Excitations
Background
Component(F)
Action Potential
Amplitude(Δ
F)
ΔF/F < 10%
Use of voltage sensitive dye: Di‐4‐ANEPPS
Suppression of contraction by 2,3‐butandione monoxime(BDM)
8
Time

9. Application of visual feedback to eletctrical stimulation
High Speed
9

10. 10