Development of high‐resolution YAP(Ce) x‐ray camera for the imaging of astatine‐211(At‐211) in small animals

Nakanishi, Keiji; Yamamoto, Seiichi; Watabe, Tadashi; Kaneda-Nakashima, Kazuko; Shirakami, Yoshifumi; Ooe, Kazuhiro; Toyoshima, Atsushi; Shinohara, Atsushi; Teramoto, Tokuo; Hatazawa, Jun; Kamada, Kei; Yoshikawa, Akira

doi:10.1002/mp.14455

Cited by 12 publications

(6 citation statements)

References 20 publications

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“…In the accumulate mode, the gamma ray images were accumulated in the preset acquisition time and the resulting image was stored in the laptop PC's -2 - memory. The positioning circuit and data-acquisition system were basically the same as those used for other experiments [12][13][14].…”

Section: Developed Simultaneous Imaging Systemmentioning

confidence: 99%

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

Nagata¹,

Yamamoto²,

Noguchi³

et al. 2021

J. Inst.

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In high-dose-rate (HDR) brachytherapy, verification of the Ir-192 source's position during treatment is needed because such a source is extremely radioactive. One of the methods used to measure the source position is based on imaging the gamma rays from the source, but the absolute position in a patient cannot be confirmed. To confirm the absolute position, it is necessary to acquire an optical image in addition to the gamma ray image at the same time as well as the same position. To simultaneously image the gamma ray and optical images, we developed an imaging system composed of a low-sensitivity, high-resolution gamma camera integrated with a CMOS camera. The gamma camera has a 1-mm-thick cerium-doped yttrium aluminum perovskite (YAIO3: YAP(Ce)) scintillator plate optically coupled to a position-sensitive photomultiplier (PSPMT), and a 0.1-mm-diameter pinhole collimator was mounted in front of the camera to improve spatial resolution and reduce sensitivity. We employed the concept of a periscope by placing two mirrors tilted at 45 degrees facing each other in front of the gamma camera to image the same field of view (FOV) for the gamma camera and the CMOS camera. The spatial resolution of the imaging system without the mirrors at 100 mm from the Ir-192 source was 3.2 mm FWHM, and the sensitivity was 0.283 cps/MBq. There was almost no performance degradation observed when the mirrors were positioned in front of the gamma camera. The developed system could measure the Ir-192 source positions in optical and gamma ray images. We conclude that the developed imaging system has the potential to measure the absolute position of an Ir-192 source in real-time clinical measurements.

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Section: Developed Simultaneous Imaging Systemmentioning

confidence: 99%

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

Nagata¹,

Yamamoto²,

Noguchi³

et al. 2021

J. Inst.

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“…In our previous study, the observation of the shape of a thyroid gland of a mouse administered [At-211]NaAt needed much higher spatial resolution (about 1.5 mm FWHM) compared with the spatial resolutions in this study [17], so the spatial resolution of a clinical scintillation camera system is not enough for imaging the distribution of At-211 in small organs of small animals, even if the LEHR collimator is used. However, a clinical scintillation system is useful for grasping the distribution in the whole body of a small animal using this imaging [10].…”

Section: Discussionmentioning

confidence: 69%

Monte Carlo approach to comparison of parallel-hole collimators of clinical scintillation camera system for imaging astatine-211 (At-211)

2022

Self Cite

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Astatine-211 (At-211) is a promising alpha particle emitter for targeted radionuclide therapy. Since its daughter isotope (polonium-211(Po-211)) emits characteristic X-rays of about 80 keV, the distribution of At-211 in the body can be imaged by detecting the X-rays with a scintillation camera. However, the isotopes also emit high-energy gamma photons that are collimated with difficulty for a parallel-hole collimator of a clinical scintillation camera system, and thus the selection of a collimator is important. In this study, we compared the performances of low-energy high-resolution (LEHR), low-energy all-purpose (LEAP), medium-energy (ME), and high-energy (HE) parallel-hole collimators for At-211 using Monte Carlo simulation. We simulated a clinical scintillation camera system with the collimators using the Geant4 toolkit. The energy spectra, sensitivities, and spatial resolutions for the point source of At-211 were evaluated. Moreover, we simulated imaging of six sphere sources of At-211 in a 1-cm-thick cylindrical phantom filled with At-211 solution to evaluate image contrast. All of the results in this study are simulation data. The spatial resolution with LEHR was 7.6 mm full width at half maximum (FWHM) and the highest between collimators, while the sensitivity with LEAP was 85 cps/MBq and the highest. The image contrast acquired with the ME collimator was superior to those with the other collimators. We concluded that the LEHR, LEAP, and ME collimators had their advantages, so an optimum collimator should be selected depending on the purpose of imaging of At-211, although there was no advantage in using the HE collimator for the imaging of At-211.

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“…12 As a last remark, let us mention that the decay of 211 At yields X-rays with energies of 77-92 keV that allow in vivo imaging for biodistribution studies in animal models. 13,14 The twofold purpose of this paper was (a) to benchmark the Monte Carlo track structure (MCTS) code TILDA-V (Transport d'Ions Lourds Dans l'Aqua & Vivo) against the well-known Particle and Heavy Ion Transport code System (PHITS), to demonstrate its usefulness for event-by-event 𝛼-particle transport; and (b) to apply TILDA-V for performing a first cell dosimetry study of 211 At.…”

Section: Introductionmentioning

confidence: 99%

Physics and small‐scale dosimetry of α$\alpha$‐emitters for targeted radionuclide therapy: The case of 211At$^{211}{\rm At}$

Alcocer‐Ávila,

Larouze,

Groetz

et al. 2024

Medical Physics

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BackgroundMonte Carlo simulations have been considered for a long time the gold standard for dose calculations in conventional radiotherapy and are currently being applied for the same purpose in innovative radiotherapy techniques such as targeted radionuclide therapy (TRT).PurposeWe present in this work a benchmarking study of the latest version of the Transport d'Ions Lourds Dans l'Aqua & Vivo (TILDA‐V ) Monte Carlo track structure code, highlighting its capabilities for describing the full slowing down of ‐particles in water and the energy deposited in cells by ‐emitters in the context of TRT.MethodsWe performed radiation transport simulations of ‐particles (10 keV –100 MeV ) in water with TILDA‐V and the Particle and Heavy Ion Transport code System (PHITS) version 3.33. We compared the predictions of each code in terms of track parameters (stopping power, range and radial dose profiles) and cellular S‐values of the promising radionuclide astatine‐211 (). Additional comparisons were made with available data in the literature.ResultsThe stopping power, range and radial dose profiles of ‐particles computed with TILDA‐V were in excellent agreement with other calculations and available data. Overall, minor differences with PHITS were ascribed to phase effects, that is, related to the use of interaction cross sections computed for water vapor or liquid water. However, important discrepancies were observed in the radial dose profiles of monoenergetic ‐particles, for which PHITS results showed a large underestimation of the absorbed dose compared to other codes and experimental data. The cellular S‐values of computed with TILDA‐V agreed within 4% with the values predicted by PHITS and MIRDcell.ConclusionsThe validation of the TILDA‐V code presented in this work opens the possibility to use it as an accurate simulation tool for investigating the interaction of ‐particles in biological media down to the nanometer scale in the context of medical research. The code may help nuclear medicine physicians in their choice of ‐emitters for TRT. Further research will focus on the application of TILDA‐V for quantifying radioinduced damage on the deoxyribonucleic acid (DNA) molecule.

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Development of high‐resolution YAP(Ce) x‐ray camera for the imaging of astatine‐211(At‐211) in small animals

Cited by 12 publications

References 20 publications

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

Monte Carlo approach to comparison of parallel-hole collimators of clinical scintillation camera system for imaging astatine-211 (At-211)

Physics and small‐scale dosimetry of α$\alpha$‐emitters for targeted radionuclide therapy: The case of 211At$^{211}{\rm At}$

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