Electron-tracking Compton Camera Research Articles

High-energy extension of the gamma-ray band observable with an electron-tracking Compton camera

Although the MeV gamma-ray band is a promising energy-band window in astrophysics, the current situation of MeV gamma-ray astronomy significantly lags behind those of the other energy bands in angular resolution and sensitivity. An electron-tracking Compton camera (ETCC), a next-generation MeV detector, is expected to revolutionize the situation. An ETCC tracks each Compton-recoil electron with a gaseous electron tracker and determines the incoming direction of each gamma-ray photon; thus, it has a strong background rejection power and yields a better angular resolution than classical Compton cameras. Here, we study ETCC events in which the Compton-recoil electrons do not deposit all energies to the electron tracker but escape and hit the surrounding pixel scintillator array (PSA). The PSA provides additional information on the electron-recoil direction, which enables us to improve significantly the angular resolution. We developed an analysis method for this untapped class of events and applied it to laboratory and simulation data. We found that the energy spectrum obtained from the simulation agreed with that of the actual data within a factor of 1.2. We then evaluated the detector performance using the simulation data. The angular resolution for the new-class events was found to be twice as good as in the previous study at the energy range 1.0–2.0 MeV, where both analyses overlap. We also found that the total effective area is dominated by the contribution of the double-hit events above an energy of 1.5 MeV. Notably, applying this new method extends the sensitive energy range with the ETCC from 0.2–2.1 MeV in the previous studies to up to 3.5 MeV. Adjusting the PSA dynamic range should improve the sensitivity in even higher energy gamma-rays. The development of this new analysis method would pave the way for future observations by ETCC to fill the MeV-band sensitivity gap in astronomy.

Evaluating the capability of detecting recoil-electron tracks using an electron-tracking Compton camera with a silicon-on-insulator pixel sensor

Sub-MeV gamma-ray line observations are crucial for the understanding of high-energy astrophysical processes. In this energy range, the presence of a significant amount of background poses a serious problem. Therefore, it is essential to reduce this background to achieve high-sensitivity observations. An electron-tracking Compton camera can efficiently mitigate the impact of background on scientific results thanks to its ability to fully resolve the Compton process. In addition if we utilize a semiconductor detector as the sensor, the electron-tracking Compton camera can achieve high-energy resolution for the detection of gamma-ray lines. To operate the electron-tracking Compton camera effectively, the sensor needs to coincidence events for each detection signal and resolve the complex structure of recoiled-electron tracks of a few hundred μm. We focused on the silicon-on-insulator pixel sensor XRPIX2b developed for X-ray observations, which satisfies requirements. We developed a prototype electron-tracking Compton camera using XRPIX2b and carried out a quantitative evaluation of its detection capability for estimating the recoil directions of electrons at various angles. As a result, we successfully detected short recoil-electron tracks with a length of 100μm corresponded to scattering angles of 30°-40° for 511 keV gamma rays entering the sensor. In term of angular resolution measure and scatter plane deviation of a reconstructed image, the evaluations showed results of 15° and 40° (full width at half maximum), respectively, in cases where 511 keV gamma rays were scattered at 90° and recoil electrons tracked the surface of the sensor detection plane. We confirmed that these results were consistent with simulation results, within approximately a 15% margin.

Quantitative visualization of a radioactive plume with harmonizing gamma-ray imaging spectrometry and real-time atmospheric dispersion simulation based on 3D wind observation

ABSTRACT To propose a novel monitoring method for the quantitative visualization of 3D distribution of a radioactive plume in the vicinity of release point and source term estimation of released radionuclides, the feasibility of its analysis method is demonstrated by preliminary test. The proposed method is the combination of gamma-ray imaging spectroscopy with the electron tracking Compton camera (ETCC) and real-time high-resolution atmospheric dispersion simulation based on 3D wind observation with Doppler lidar. ETCC can acquire the angle distribution images of direct gamma-ray from a specific radionuclide in a target radioactive plume by quantitatively capturing gamma-ray incidence angles and spectrum distributions. The 3D distribution of each radionuclide in the radioactive plume is inversely reconstructed from direct gamma-ray images of each radionuclide by several ETCCs located around the target by harmonizing with the air concentration distribution pattern of the plume predicted by real-time atmospheric dispersion simulation. A prototype of the analysis method was developed, showing a sufficient performance in several test cases using hypothetical data generated by numerical simulations of atmospheric dispersion and radiation transport. The proposed method is expected to become an innovative monitoring framework for nuclear emergency.

First Observation of the MeV Gamma-Ray Universe with Bijective Imaging Spectroscopy Using the Electron-tracking Compton Telescope on Board SMILE-2+

MeV gamma-rays provide a unique window for the direct measurement of line emissions from radioisotopes, but observations have made little significant progress since COMPTEL on board the Compton Gamma-ray Observatory (CGRO). To observe celestial objects in this band, we are developing an electron-tracking Compton camera (ETCC) that realizes both bijective imaging spectroscopy and efficient background reduction gleaned from the recoil-electron track information. The energy spectrum of the observation target can then be obtained by a simple ON–OFF method using a correctly defined point-spread function on the celestial sphere. The performance of celestial object observations was validated on the second balloon SMILE-2+ , on which an ETCC with a gaseous electron tracker was installed that had a volume of 30 × 30 × 30 cm3. Gamma-rays from the Crab Nebula were detected with a significance of 4.0σ in the energy range 0.15–2.1 MeV with a live time of 5.1 hr, as expected before launch. Additionally, the light curve clarified an enhancement of gamma-ray events generated in the Galactic center region, indicating that a significant proportion of the final remaining events are cosmic gamma-rays. Independently, the observed intensity and time variation were consistent with the prelaunch estimates except in the Galactic center region. The estimates were based on the total background of extragalactic diffuse, atmospheric, and instrumental gamma-rays after accounting for the variations in the atmospheric depth and rigidity during the level flight. The Crab results and light curve strongly support our understanding of both the detection sensitivity and the background in real observations. This work promises significant advances in MeV gamma-ray astronomy.

Development of convolutional neural networks for an electron-tracking Compton camera

Abstract The Electron-Tracking Compton Camera (ETCC), which is a complete Compton camera that tracks Compton scattering electrons with a gas micro time projection chamber, is expected to open up MeV gamma-ray astronomy. The technical challenge for achieving several degrees of the point-spread function is precise determination of the electron recoil direction and the scattering position from track images. We attempted to reconstruct these parameters using convolutional neural networks. Two network models were designed to predict the recoil direction and the scattering position. These models marked 41$^\circ$ of angular resolution and 2.1 mm of position resolution for 75 keV electron simulation data in argon-based gas at 2 atm pressure. In addition, the point-spread function of the ETCC was improved to 15$^\circ$ from 22$^\circ$ for experimental data from a 662 keV gamma-ray source. The performance greatly surpassed that using traditional analysis.

MeV Gamma-ray imaging spectroscopic observation for Galactic Centre and Cosmic Background MeV gammas by SMILE-2+ Balloon Experiment

Recently, there appears lots of papers on the possibility of light Dark Matter (DM) in MeV and sub-GeV scale. Until now, only INTEGRAL and COMPTEL provided experimental data of 511keV of galactic center, and two spectra of Galactic Diffuse MeV gammas (GDMG) and COMPTEL provided the Cosmic Background MeV gammas (CBMG) for wide sky for indirect detection of light DMs. However except 511keV, those spectra for diffuse gammas included large statistical and systematic errors in spite of 10 years observation, since both two instruments suffered from severe background radiation in space. In 2018 April, we (SMILE-project in Comic-ray Group of Kyoto University) have observed MeV gamma rays for whole southern sky by Electron Tracking Compton Camera (ETCC) using JAXA balloon at Australia during one-day. (SMILE2+ Project) By measuring all parameters of Compton scattering in every gamma, ETCC has achieved for the first time to obtain the complete direction of MeV gammas as same as optical telescopes, and also to distinguish signal gammas from huge background gammas in space clearly. In this observation, ETCC with a large Field of View of 3sr observed MeV gammas from 3/5 of all sky including galactic centre, a half disk, crab, and most of CBMG By reconstructing the Compton process, we successfully obtained pure comic gammas by reducing background by more 2 orders, which is clearly certificated by the clear enhancement of detected gamma flux with ˜30% during galactic center passing through the Field of View, which is consistent with the ratio of CBMG and GDMG. Now 511keV gammas GDMG are preliminarily detected with ˜5 and >10σ respectively around Galactic Centre. Also we have obtained near 105events of CBMG in with quite low background of only a few 10% in total CBMG events. Thus we obtained good data for both with high statistics and very low systematics even one day observation.

Simulation study on SOI based electron tracking Compton camera using deep learning method

Compton imaging is a promising method of sub MeV to a few MeV gamma-rays and expected to use in various application field, such as medical imaging, environmental monitoring and astrophysics. Several types of Compton camera has beed developed using different materials. One of the drawbacks in conventional Compton imaging is relatively low signal to background ratio caused by its projected Compton cones. Recoil electron tracking is one straight-forward way to improve the signal-to-background ratio, however, it is only realized in gaseous detectors. The realization of electron tracking in solid detectors is under investigation because of its short track in scatter materials. We demonstrated the capability of electron tracking in silicon-on-insulator (SOI) pixel detector with 30 μm pixels size. The extraction of ejected direction of recoil electrons in Compton scattering is an important problem. In this work, we investigated the use of deep learning for estimating the angle in plane and depth using Geant 4 Monte Carlo simulation. The effect of pixel size to the estimation accuracy and SPD is characterized for the application of actual silicon-on-insulator based SOI detectors. The imaging capability is also characterized using predicted recoil electron direction.

Electron-tracking Compton camera imaging of technetium-95m.

Imaging was conducted using an electron tracking-Compton camera (ETCC), which measures γ-rays with energies in the range of 200–900 keV from 95mTc. 95mTc was produced by the 95Mo(p, n)95mTc reaction on a 95Mo-enriched target. A method for recycling 95Mo-enriched molybdenum trioxide was employed, and the recycled yield of 95Mo was 70%-90%. Images were obtained with the gate of three energies. The results showed that the spatial resolution increases with increasing γ-ray energy, and suggested that the ETCC with high-energy γ-ray emitters such as 95mTc is useful for the medical imaging of deep tissue and organs in the human body.

95gTc and 96gTc as alternatives to medical radioisotope 99mTc

We studied 95gTc and 96gTc as alternatives to the medical radioisotope 99mTc. 96gTc (95gTc) can be produced by (p, n) reactions on an enriched 96Mo (95Mo) target with a proton beam provided by a compact accelerator such as a medical cyclotron that generate radioisotopes for positron emission tomography (PET). The γ-rays are measured with an electron-tracking Compton camera (ETCC). We calculated the relative intensities of the γ-rays from 95gTc and 96gTc. The calculated γ-ray intensity of a 96gTc (95gTc) nucleus is as high as 63% (70%) of that of a 99mTc nucleus. We also calculated the patient radiation doses of 95gTc and 96gTc, which were larger than that of 99mTc by a factor of 2–3 based on the applied assumptions. A medical PET cyclotron which can provide proton beams with energies of 11–12 MeV and a current of 100 μA can produce 12 GBq (39 GBq) of 96gTc (95gTc) for operation time of 8 h, which can be used for 240 (200) diagnostic scans.

Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

Abstract X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factor over an FoV of up to 2π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 107 s exposure and over 20 GRBs down to a 6 × 10−6 erg cm−2 fluence and 10% polarization during a one-year observation.

First On-Site True Gamma-Ray Imaging-Spectroscopy of Contamination near Fukushima Plant

We have developed an Electron Tracking Compton Camera (ETCC), which provides a well-defined Point Spread Function (PSF) by reconstructing a direction of each gamma as a point and realizes simultaneous measurement of brightness and spectrum of MeV gamma-rays for the first time. Here, we present the results of our on-site pilot gamma-imaging-spectroscopy with ETCC at three contaminated locations in the vicinity of the Fukushima Daiichi Nuclear Power Plants in Japan in 2014. The obtained distribution of brightness (or emissivity) with remote-sensing observations is unambiguously converted into the dose distribution. We confirm that the dose distribution is consistent with the one taken by conventional mapping measurements with a dosimeter physically placed at each grid point. Furthermore, its imaging spectroscopy, boosted by Compton-edge-free spectra, reveals complex radioactive features in a quantitative manner around each individual target point in the background-dominated environment. Notably, we successfully identify a “micro hot spot” of residual caesium contamination even in an already decontaminated area. These results show that the ETCC performs exactly as the geometrical optics predicts, demonstrates its versatility in the field radiation measurement, and reveals potentials for application in many fields, including the nuclear industry, medical field, and astronomy.

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that “Electron Tracking Compton Camera” (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

Electron Pattern Recognition using trigger mode SOI pixel sensor for Advanced Compton Imaging

Compton imaging is a useful method for localizing sub MeV to a few MeV gamma-rays and widely used for environmental and medical applications. The direction of recoiled electrons in Compton scattering process provides the additional information to limit the Compton cones and increases the sensitivity in the system. The capability of recoiled electron tracking using trigger-mode Silicon-On-Insulator (SOI) sensor is investigated with various radiation sources. The trigger-mode SOI sensor consists of 144 by 144 active pixels with 30 μm cells and the thickness of sensor is 500 μm. The sensor generates the digital output when it is hit by gamma-rays and 25 by 25 pixel pattern of surrounding the triggered pixel is readout to extract the recoiled electron track. The electron track is successfully observed for 60Co and 137Cs sources, which provides useful information for future electron tracking Compton camera.

AN ELECTRON-TRACKING COMPTON TELESCOPE FOR A SURVEY OF THE DEEP UNIVERSE BY MeV GAMMA-RAYS

Photon imaging for MeV gammas has serious difficulties due to huge backgrounds and unclearness in images, which are originated from incompleteness in determining the physical parameters of Compton scattering in detection, e.g., lack of the directional information of the recoil electrons. The recent major mission/instrument in the MeV band, Compton Gamma Ray Observatory/COMPTEL, which was Compton Camera (CC), detected mere $\sim30$ persistent sources. It is in stark contrast with $\sim$2000 sources in the GeV band. Here we report the performance of an Electron-Tracking Compton Camera (ETCC), and prove that it has a good potential to break through this stagnation in MeV gamma-ray astronomy. The ETCC provides all the parameters of Compton-scattering by measuring 3-D recoil electron tracks; then the Scatter Plane Deviation (SPD) lost in CCs is recovered. The energy loss rate (dE/dx), which CCs cannot measure, is also obtained, and is found to be indeed helpful to reduce the background under conditions similar to space. Accordingly the significance in gamma detection is improved severalfold. On the other hand, SPD is essential to determine the point-spread function (PSF) quantitatively. The SPD resolution is improved close to the theoretical limit for multiple scattering of recoil electrons. With such a well-determined PSF, we demonstrate for the first time that it is possible to provide reliable sensitivity in Compton imaging without utilizing an optimization algorithm. As such, this study highlights the fundamental weak-points of CCs. In contrast we demonstrate the possibility of ETCC reaching the sensitivity below $1\times10^{-12}$ erg cm$^{-2}$ s$^{-1}$ at 1 MeV.

New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)

For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10×10×15cm3 TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30cm)3 medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector system. In addition, the event rate is also expected to dramatically increase during observation. Here, we describe both the concept and the performance of the new data-acquisition system with this (30cm)3 ETCC to manage 100 times more data while satisfying the severe restrictions regarding the weight and power consumption imposed by a balloon-borne observation. In particular, to improve the detection efficiency of the fine tracks in the TPC from ~10% to ~100%, we introduce a new data-handling algorithm in the TPC. Therefore, for efficient management of such large amounts of data, we developed a data-acquisition system with parallel data flow.

A performance study of an electron-tracking Compton camera with a compact system for environmental gamma-ray observation

An electron-tracking Compton camera (ETCC) is a detector that can determine the arrival direction and energy of incident sub-MeV/MeV gamma-ray events on an event-by-event basis. It is a hybrid detector consisting of a gaseous time projection chamber (TPC), that is the Compton-scattering target and the tracker of recoil electrons, and a position-sensitive scintillation camera that absorbs of the scattered gamma rays, to measure gamma rays in the environment from contaminated soil. To measure of environmental gamma rays from soil contaminated with radioactive cesium (Cs), we developed a portable battery-powered ETCC system with a compact readout circuit and data-acquisition system for the SMILE-II experiment [1,2]. We checked the gamma-ray imaging ability and ETCC performance in the laboratory by using several gamma-ray point sources. The performance test indicates that the field of view (FoV) of the detector is about 1 sr and that the detection efficiency and angular resolution for 662 keV gamma rays from the center of the FoV is (9.31 ± 0.95) × 10−5 and 5.9° ± 0.6°, respectively. Furthermore, the ETCC can detect 0.15 μSv/h from a 137Cs gamma-ray source with a significance of 5σ in 13 min in the laboratory. In this paper, we report the specifications of the ETCC and the results of the performance tests. Furthermore, we discuss its potential use for environmental gamma-ray measurements.

Performance of a new Electron-Tracking Compton Camera under intense radiations from a water target irradiated with a proton beam

We have developed an electron-tracking Compton camera (ETCC) for use in next-generation MeV gamma ray telescopes. An ETCC consists of a gaseous time projection chamber (TPC) and pixel scintillator arrays (PSAs). Since the TPC measures the three dimensional tracks of Compton-recoil electrons, the ETCC can completely reconstruct the incident gamma rays. Moreover, the ETCC demonstrates efficient background rejection power in Compton-kinematics tests, identifies particle from the energy deposit rate (dE/dX) registered in the TPC, and provides high quality imaging by completely reconstructing the Compton scattering process. We are planning the ``Sub-MeV gamma ray Imaging Loaded-on-balloon Experiment'' (SMILE) for our proposed all-sky survey satellite. Performance tests of a mid-sized (30 cm)3 ETCC, constructed for observing the Crab nebula, are ongoing. However, observations at balloon altitudes or satellite orbits are obstructed by radiation background from the atmosphere and the detector itself [1]. The background rejection power was checked using proton accelerator experiments conducted at the Research Center for Nuclear Physics, Osaka University. To create the intense radiation fields encountered in space, which comprise gamma rays, neutrons, protons, and other energetic entities, we irradiated a water target with a 140 MeV proton beam and placed a SMILE-II ETCC near the target. In this situation, the counting rate was five times than that expected at the balloon altitude. Nonetheless, the ETCC stably operated and identified particles sufficiently to obtain a clear gamma ray image of the checking source. Here, we report the performance of our detector and demonstrate its effective background rejection based in electron tracking experiments.

Development of a 30 cm-cube Electron-Tracking Compton Camera for the SMILE-II Experiment

To explore the sub-MeV/MeV gamma-ray window for astronomy, we have developed the Electron-Tracking Compton Camera (ETCC), and carried out the first performance test in laboratory conditions using several gamma-ray sources in the sub-MeV energy band. Using a simple track analysis for a quick first test of the performance, the gamma-ray imaging capability was demonstrated with clear images and 5.3 degrees of angular resolution measure (ARM) measured at 662 keV. As the greatest impact of this work, a gamma-ray detection efficiency on the order of 10−4 was achieved at the sub-MeV gamma-ray band, which is one order of magnitude higher than our previous experiment. This angular resolution and detection efficiency enables us to detect the Crab Nebula at the 5σ level with several hours observation at balloon altitude in middle latitude. Furthermore, good consistency of efficiencies between this performance test and simulation including only physical processes is very important; it means we achieve nearly 100% detection of Compton recoil electrons and means that our predictions of performance enhancement resulting from future upgrades are more realistic. We are planning to confirm the imaging capability of the ETCC by observation of celestial objects in the SMILE-II (Sub-MeV gamma ray Imaging Loaded-on-balloon Experiment II). The SMILE-II and following SMILE-III project will be an important key of sub-MeV/MeV gamma-ray astronomy.

SU-C-144-01: Imaging Study of An Electron-Tracking Compton Camera for Nuclear Medicine

Purpose: Conventional gamma-ray detector, PET and SPECT, have the limitation of energy. These limitations are major problems of studying for a new medical imaging. Therefore, we have developed the new imaging detector which is an electron-tracking Compton camera (ETCC). We show results of the update ETCC system and show the imaging Result of 95m-Tc which is one of the targets for new imaging reagents. Methods: The ETCC has a wide energy dynamic range and wide field of view. Also the ETCC can detect recoil-electron tracks which are generated from Compton scattering. We have developed the new ETCC system which have been modified the logic of catching the electron tracks and have better performance compared with old system. The 99m-Tc is the most important radioisotopes which are used in nuclear medicine. However, the lifetime of the 99m-Tc is 6 hours, it may not be possible to use imaging reagent for using antibody reaction because of accumulation time. The technetium, however, have many isotopes and many energy peaks. If we can reconstruct gamma rays which have various energy peaks, imaging technology for nuclear medicine will progress. The 95m-Tc (204, 582, 835 keV ) is one of the targets for a new imaging reagent. In this presentation, we show the new ETCC system performance and 95m-Tc imaging results. Results: ETCC achieved a wide energy dynamic range (200–1300keV) and wide field of view. We could catch the recoil electron tracks clearly using new ETCC system, and we succeeded in imaging of the 95m-Tc. Conclusion: We have developed the ETCC for new medical imaging device and succeeded in imaging of the 95m-Tc. We started to develop the ETCC which can image the mouse within 30 min. Thus, this detector has the possibility of new medical imaging.

SU-E-I-63: Performance Study of An Electron-Tracking Compton Camera for Medical Imaging.

Conventional gamma-ray detector, PET and SPECT, have the limitation of energy and field of view. These limitations are major problems of studying for a new medical imaging. Therefore, we have developed the new imaging detector which is an electron-tracking Compton camera (ETCC). A reconstruction method of Compton camera (CC) is using the physics principle. Because of using physics principle, CC can have a wide energy dynamic range and wide field of view. Conventional CC, however, cannot catch Compton recoil electron tracks, and this is one of the reasons of low imaging power. We have developed a time projection chamber (TPC) using micro pixel chamber (μPIC) as the new detector for ETCC. The μPIC is 2-dimensional gaseous detector and this position resolution is less than 400 μm. Using this detector, ETCC can get electron tracks which are generated from Compton scattering. In this paper, we show the prototype ETCC performance and imaging results. ETCC achieved a wide energy dynamic range (200-1300keV) and wide field of view (3 steradian). Also we succeeded in imaging new imaging reagents using mice as follows; (1) F-18-FDG (511 keV) and I-131-MIBG (364 keV) simultaneous imaging for double clinical tracer imaging, (2) Zn-65- porphyrin (1116 keV) imaging for high energy gamma-ray imaging and, (3) imaging of some minerals (Mn-54, Zn-65) in mice and so on. And we succeeded in 3-D imaging which has imaged only one direction using one head camera. We have developed the ETCC for new medical imaging device and succeeded in imaging the some imaging reagents. We started to develop the new ETCC which can image the mouse within 30 min. Thus, this detector has the possibility of new medical imaging.