1. 1)Dep. of Phys, Kyoto Univ., Kyoto, Japan,
On-time Imaging of the distribution of 10B in BNCT by the detection of 478keV prompt gammas with Electron Tracking Compton Camera (ETCC)
TPC
Pixel Scintillator Arrays (PSA)
RI reagent
40cm
New Medical ETCC made by Kyoto COI project (2015)
First Medical ETCC(2008)
Introduction of Electron Tracking Compton Camera (ETCC)
ETCC in Medical Imaging
Result from Neutron Beam test
Summary
16/Dec/2015
T.Tanimori1 A.Takada, T.Mizumoto, S.Sonoda, D.Tomono
on behalf of SMILE team
1)Dep. of Phys, Kyoto Univ., Kyoto, Japan,

2. Electron-Tracking Compton Camera (ETCC) in Astro
ARM (Angular Resolution Measure)
SPD (Scatter Plane Deviation)
30cm-cube Gaseous Time Projection Chamber
--- tracking of recoil electron ---
SPD (Scatter Plane Deviation) + dE/dx + a
Scintillator Array for scattered g
Gaseous TPC
Large Field of View >4 str
m-PIC
Scintillator Array
SPD ~100o
Image of 3 point sources(662keV) with several SPD resolution
no use of SPD
SPD 90o (<80keV) SPD 45o (>80keV)
SPD ~200o
SPD ~100o

3. Imaging and Point Spread Function (PSF)
General Imaging
(measures q and f)
Two directional angles
f(q, f) = x
g(q, f) = y
Transformation
Compton Imaging (only q )
Electron Tracking Imaging
imaging with q and f
PSF(Q ~20-40o) (Q ~ average of q) Q
imaging
with only q
PSF(Q ~1o)
SPD g e q g’ f
2D position q f CC y x
Compton Camera -> only electrically collimated
ETCC -> Electrically Focused
Tanimori et al., ApJ (2015), 810, 28

4. Point Spread Function in Compton Camera
Efficiency for analyzed gammas useful imaging
SMILE-I type ETCC
10 cm-cubic, Ar (1 atm), 1 R.L.
30 cm-cubic Ar (1 atm), 1 R.L.
30 cm-cubic
Ar (1 atm), 3 R.L.
40 cm-cubic CF4 (3 atm), 3 R.L.
50 cm-cubic, CF4 (3 atm), 10 R.L.
10-2
10-3
10-4
10-5
PSF(q) =½ gammas from point in radius of q
Efficiency
Conventional CC PSF(3-50o)
SPD 50o ARM 5o PSF(7o)
SPD 25o ARM 5o PSF(5o)
SPD 5o ARM 2o PSF(1.2o)
PSF of Compton Camera is by  (NOT by ARM).
PSF of ETCC is Max{ARM, SPD}
Sensitivity is perfectly determined by Eff. x PSF
ARM
SPD
Conventional CC
120o

5. Compact ETCC for multipurpose medical imaging
10x10x10cmETCC (2014)
Clear images for >300keV g in mice (08-12)
(I-131:364keV)
Thyroid gland phantom from one direction　
364keV
10x10x15cmETCC (15)
Tacking efficiency 10% -> 100%
Fast DAQ 30Hz -> ~1KHz
Good Angular resolution 10o ->5o x5
improved
1st Medical 10cm-cube ETCC(06~12)
Multicolor image (3 energy gs) 2014type ETCC
W(I-131:364keV)
2015
2014
2006 5

6. Proton Therapy Beam-on Imaging with advanced ETCC for Astrophysics
Strong Background
Rejection by dE/dx
of tracks in gas TPC
140MeV p-bean
~1nA at RCNP of
Osaka Univ.

7. Imaging Test in Neutron Beam
KUANS Compact neutron source (Kyoto)
3.5MeV p-lineac + Be target
thermal neutron /cm2s (3x103 cm2s)
Target 10B 4x10-3mol -> body ~20kg
Polyethylene (5%B) target Ge
ETCC
Thermal n
40cm
ETCC 10x10x15cm 1.5atm Ar
Efficiency
Trigger rate ~15Hz (6hrs Observ.)
Back Projection of 478±47keV
D=8cm
ETCC Energy Spectrum Ge

8. Separation of 478keV from511keV
22Na source set on Polyethylene brock
22Na is quite stronger than 478keV from 10B
478 keV±15%
478 keV -15% ~ -7.5%
511 keV +7.5% ~+15%
Poly-brock
22Na Ge
ETCC Energy Spectrum GSO DE/E ~12%
Main Position source -> possibly Collimator
In ETCC Observation,
511keV is expected to smaller flux than 478keV
Even if 511keV appeared strongly,
GAGG DE/E ~6% eparation is OK and
Imaging gives quite strong separation !!

9. BNCT-SPECT is Possible?D L T DW
D+t
Type D
(mm) T L
Aperture (D/(D+T))2
DW (D/L)2
Weight
30x30cm
(kg) lead
99mTc :140keV
1.4
0.15 32
0.82
2.1x10-3
5.9
High E,300keV
3.1
2.0 60
0.37
2.7x10-3
22.6
BNCT 487keV 2 12
200
0.02
10-4
204
SPECT
Au-198(410keV
Typical dose for SPECT 500MBq
Similar number of g for BNCT-SPECT
0.5 x550 ~ 250GBq needed
BNCT 106g/cc.s. 10kg-> g/s 10GBq
Heavy collimator => Strong Background Source .

10. Imaging for Boron chemicals in BNCT
Imaging of Boron chemicals(BC)
BC+ 18F for PET
However, no guarantee for BC+18F with same distribution as BC in body
Imaging for BNCT in human
10B a few mmol/cc human 6x104g
ETCC eff. 1x10-3 x 3-5 modules
Required 478keV g 105 gammas/5kg
(5-7mm resolution)
Measurement Time a few 10sec.
Needed neutron flux 106n/cm2s
3 order weaker beam than treatment -> Modulated Mode
Imaging System of mice is inevitable for developing new BCs
10B a few mmol/cc mouse 20g
Use enhanced 10B ETCC eff. 5x10-4
Required 478keV gammas ~ (1-2mm resolution)
Measurement time 100sec.
Needed neutron flux 106n/cm2s
Next Development for Medical ETCC
( a few years later)
Resolution　-> 2-3mm in human
Efficiency　 -> >1% (3atm CF4 20cmETCC)
High counting rate ~100KHz
Solution:
Small neutron source + ETCC

11. Features of ETCC for Molecular Imaging & Nuclear Medicine
ETCC provides clear images by well-defined PSF similar to Optical camera with small background
ETCC would be a versatile gamma-ray imager in Medicine covering gammas from lots of RIs.
ETCC would enable following new approaches
Low Dose Imaging
New Tracers with new RIs (decay time ~1day) Visualizations of immunity and enzyme :
Multi RI Tracer Image 99mTc +18F
Imaging for beam therapy (proton, ion, BNCT) 　　　　　　　 　　

12. Acknowledgements
SMILE Team: H.Kubo1,, S.Iwaki1, T.Kishimoto1, S.Komura1, Y.Matsuoka1, , T.Miyamoto, K.Miuchi2 Y.Mizumura1, K.Nakamura1, M.Oda1, J.D.Parker1, T.Sawano3 ,S.Sonoda1, T.Takemura1, 1)Dep. of Physics, Kyoto University, Japan, 2) Dep.of Physics, Kobe University, Japan, 3)Dep. of Physics, Kanazawa University, Japan
Center of Innovation Program in Kyoto University(The Last 5X innovation R&D Center for a Smart, Happy, and Resilient Society) with CANON co. Ltd.
Prof. H.Kimura : Department of Analytical & Bioinorganic Chemistry, Kyoto pharmaceutical University Japan
Prof. T.Nagae, Dr. H.Fujioka, Mr. M.Hirose, Hadron Group, Department of Physics, Kyoto Univ. Japan
Dr. S.Kabuki, Department of Medicine, Tokai Univ. Japan

13. Supplemental slides

14. SPD resolution in TPC with mPIC
Multiple scattering angle
e- energies
E>80kev
E<80kev
Present 800mm pitch
Linear Fitting
Between vertex to 1cm
Electron track
vertex
1cm
U,V,X electrodes in TPC
Spline Fitting Between vertex to 0.5cm
Scattering 1mm in gas
=> <1mm in Solid state
Real hits
500keV Gamma Ee ~150keV SPD: 15o - 5o
>1MeV Gamma Ee ~300keV SPD: 10o - 2o
PSF(q =1.2o) SPD 5o ARM 2o PSF(q ) q -> 1o~2o possible

15. Comparison with Semi-Conductor in Medical use
With Similar cost
Type
BG rejection
ARM＠511keV
+PSF
Efficiency
Analysis time
Area (cm2)
Detectable
gamma
(relative) Ge ×
~2o
(~50o)
Few %
x ~10
3ｘ3
　~10 Si
~3o
(50o)
few %
5x5
~10
Gas　ETCC ○
>x 　
(1~10o)
0.1~a few %
　　　１
30ｘ30
　100～ 1000