Photo-Medical Research Cooperation

11-2 One Optical Fiber Can Both Observe and Treat–Development of Extra-Fine Endoscope with Laser Radiation
Function–
Umbilical
cord B

Umbilical
cord AAmniocentesis(symptomatic treatment)

Laser source Coupling device
TV monitor

Fetal endoscope

Excess blood

Placenta
Vascularcauterization bylaser irradiation(radical treatment)

Vascularanastomoses

PC monitor

Umbilical
cord

Mono-villus,
diamniotic twins
Approximately 45 to 50%
of all Japanese twins areof the mono-villus,
biamniotic type, of whom
10 to 15% may develop
TTTS as a complication.

UterusPlacenta
Excessamniotic
fluid

Insufficient blood,
Insufficientamniotic fluid

Treatment of TTTS: Increases the likelihood of both fetuses
being delivered normally

Light source
for illumination

Anastomotic vessels
in the placenta cut
using a laser

Fig.11-7 Example of congenital disease: Twin-to-Twin Transfusion
Syndrome (TTTS)
In TTTS, the blood vessels to twins become connected inside theplacenta, resulting in one twin receiving less blood than the other. If
left untreated, there is a 70% or greater probability that one or bothfetuses will die. A radical treatment is vascular cauterization method bylaser irradiation (FLP).
The laser can be targetedat the center of the image

Abdominal side
Placenta

Blood vessel (simulation)

UterusBack sidePC

Composite-type
optical fiberscope

Fig.11-8 Extra-fine endoscope having a laser
radiation function
We produced a trial system which performs laser
radiation and observation at the same time by
one optical fiberscope with an outside diameterof 2 mm.

Fig.11-9 Technology that enables placenta
treatment at all positions
This device enables treatment even if theplacenta is in front.

Bent-type external pipe
(containing composite-type optical fiberscope)

Twin to twin transfusion syndrome (popular name TTTS) is
one of the congenital diseases that twins develop in utero. Thisdisease that only occurs in cases consisting of two amnions andone placenta (mono-villus diamniotic twins) requires highly
advanced medical treatment. In the case of normal monovillus diamniotic-twins, each blood vessel is connected to theplacenta and the balance of blood circulating through each isgood. When blood flow between twins becomes unbalanced,
and blood continues flowing to only one fetus, TTTS develops.
A laser treatment method while observing with an endoscope(popular name FLP) recently is attracting attention as a radical
therapy of TTTS, (Fig.11-7).
However, experience in FLP treatment is superficial
nationwide, and the reality is that there are only a few hospitals
nationwide that can perform FLP treatment. In addition, there
are the following problems because this treatment is intended
for a fetus floating in the uterus (in amniotic fluid) which isa small space; (1) the definite vascular configuration (a map)of connection to the placenta is not clear, (2) the distance
between the tip of the optical fiber and a blood vessel is notclear, (3) quantitative determination whether the bloodstream
is stopped or not is not possible, (4) the endoscope image isnarrow, and (5) it is hard if the placenta is in front of the fetuses(placenta previa). Advanced technical progress and a highly

skilled doctor are necessary to do such an operation with theconventional endoscope.
Therefore to make a contribution to FLP treatment, byutilizing a composite-type optical fiber by which observationand laser irradiation are possible in one optical fiber at thesame time, we produced a device which promises to solve theproblems with the conventional endoscope (Fig.11-8). We notethat this device was created as a spin-off from development ofa robot for inspecting and maintaining nuclear fusion reactors.
In this system, the middle of an image can be laser-irradiated,
and there are functions to measure the distance to an object
and blood quantity/flow speed. This allows laser radiation to
be applied precisely, safely and comparatively easily. Thisinstrument has potential for prenatal surgical treatment of
the congenital disease mentioned above. In addition, thismakes laser radiation easy even in the case of placenta previa(Fig.11-9). Furthermore, because the diameter of the hole(possibly through the abdomen) can be reduced by reducing
the endoscopic external diameter to as little as 2 mm, we canexpect that the burden to a mother's body will be reduced
greatly (Minimally Invasive Treatment). The efficacy of thissystem has already been confirmed in animal experiments.
We are proceeding with development for clinical applications
now.

Reference
Oka, K., Development of Extra-fine Endoscope Having a Laser Radiation Function -We Apply It to Prenatal Treatment-, Energy Review, vol.27, no.7, 2007,
p.7-10 (in Japanese).

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JAEA R&D Review 2008