Multispectral photon-counting for medical imaging and beam characterization

Brücken, E.; Bharthuar, S.; Emzir, Muhammad F.; Golovleva, M.; Gädda, A.; Hostettler, Roland; Härkönen, J.; Kirschenmann, S.; Litichevskyi, V.; Luukka, P.; Martikainen, L.; Naaranoja, T.; Ninca, Ilona; Ott, J.; Petrow, H.; Purisha, Zenith; Siiskonen, T.; Särkkä, Simo; Tikkanen, Joonas; Tuuva, T.; Winkler, Alexander

doi:10.1088/1748-0221/15/02/c02024

Cited by 5 publications

(7 citation statements)

References 25 publications

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“…For such a system, one would need to differentiate between the radiation types. With the multispectral CdTe detector it is in principle possible to register the prompt 𝛾-radiation from the 10 B(n,𝛼) 7 Li * reaction in the cancer cell as well as the 𝛾-radiation from the neutron background, reacting with the Cd in the detector via 113 Cd(n,𝛾) 114 Cd [2,17]. For this, spectrum-per-pixel information is needed to distinguish the radiation origin (dosimetry) and furthermore reconstruct the passed material with the different tissue types (monitoring).…”

Section: Reconstruction Of Multispectral Imagesmentioning

confidence: 99%

“…The ROC has a layout of 52 columns and 80 rows, accounting for 4160 pixel connections, with a pixel size of 100×150 𝜇m 2 . The processing procedure is described in more detail in [2,5,6]. However, the processing of Cadmium Telluride is more complicated than for standard materials such as silicon: it is a brittle material and we face problems such as cracking damages during processing, delamination of the insulation material, differences between the front and back sides of the crystals, and high leakage current of the manufactured detector.…”

Section: Introductionmentioning

confidence: 99%

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Quality assessment of Cadmium Telluride as a detector material for multispectral medical imaging

Kirschenmann,

Bezak,

Bharthuar

et al. 2022

Preprint

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Cadmium Telluride (CdTe) is a high-Z material with excellent photon radiation absorption properties, making it a promising material to include in radiation detection technologies. However, the brittleness of CdTe crystals as well as their varying concentration of defects necessitate a thorough quality assessment before the complex detector processing procedure. We present our quality assessment of CdTe as a detector material for multispectral medical imaging, a research which is conducted as part of the Consortium Project Multispectral Photon-counting for Medical Imaging and Beam characterization (MPMIB). The aim of the project is to develop novel CdTe detectors and obtain spectrum-per-pixel information that make the distinction between different radiation types and tissues possible. To evaluate the defect density inside the crystals -which can deteriorate the detector performance -we employ infrared microscopy (IRM). Posterior data analysis allows us to visualise the defect distributions as 3D defect maps. Additionally, we investigate front and backside differences of the material with current-voltage (IV) measurements to determine the preferred surface for the pixelisation of the crystal, and perform test measurements with the prototypes to provide feedback for further processing. We present the different parts of our quality assessment chain and will close with first experimental results obtained with one of our prototype PC detectors in a small tomographic setup.

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Section: Reconstruction Of Multispectral Imagesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quality assessment of Cadmium Telluride as a detector material for multispectral medical imaging

Kirschenmann,

Bezak,

Bharthuar

et al. 2022

Preprint

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“…The presented research is part of the project Multispectral Photon-counting for Medical Imaging and Beam characterization (MPMIB), funded via the Academy of Finland RADDESS programme [1]. The MPMIB project focuses on the development of a next-generation radiation detection system operating in a photon-counting (PC) mode [2]. The goal is the extraction of spectrum-per-pixel data, which will lead to higher efficiency and image quality, as well as the possibility to identify different materials and tissue types.…”

Section: Introductionmentioning

confidence: 99%

“…1 The ROC has a layout of 52 columns and 80 rows, accounting for 4160 pixel connections, with a pixel size of 100 × 150 μm 2 . The processing procedure is described in more detail in [2,5,6]. However, the processing of cadmium telluride is more complicated than for standard materials such as silicon: it is a brittle material and we face problems such as cracking damages during processing, delamination of the insulation material, differences between the front and back sides of the crystals, and high leakage current of the manufactured detector.…”

Section: Introductionmentioning

confidence: 99%

Quality assessment of cadmium telluride as a detector material for multispectral medical imaging

et al. 2022

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Cadmium telluride (CdTe) is a high-Z material with excellent photon radiation absorption properties, making it a promising material to include in radiation detection technologies. However, the brittleness of CdTe crystals as well as their varying concentration of defects necessitate a thorough quality assessment before the complex detector processing procedure. We present our quality assessment of CdTe as a detector material for multispectral medical imaging, a research which is conducted as part of the Consortium Project Multispectral Photon-counting for Medical Imaging and Beam characterization (MPMIB). The aim of the project is to develop novel CdTe detectors and obtain spectrum-per-pixel information that make the distinction between different radiation types and tissues possible. To evaluate the defect density inside the crystals — which can deteriorate the detector performance — we employ infrared microscopy (IRM). Posterior data analysis allows us to visualise the defect distributions as 3D defect maps. Additionally, we investigate front and backside differences of the material with current-voltage (IV) measurements to determine the preferred surface for the pixelisation of the crystal, and perform test measurements with the prototypes to provide feedback for further processing. We present the different parts of our quality assessment chain and will close with first experimental results obtained with one of our prototype photon-counting detectors in a small tomographic setup.

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“…Improved medical devices and technologies are crucial in the fight against cancer. A novel direct detection system based on photon counting (PC), which registers the energies of the incoming photons in every pixel of the radiation detector as described in [1], would mean a significant advancement. For such a system a detector material is needed which can cope with high fluence rates, has a good stopping power, allows for a fast readout and energy discrimination, and is PC-capable.…”

Section: Introductionmentioning

confidence: 99%

Employing infrared microscopy (IRM) in combination with a pre-trained neural network to visualise and analyse the defect distribution in Cadmium Telluride crystals

Kirschenmann,

Bharthuar,

Brücken

et al. 2021

Preprint

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While Cadmium Telluride (CdTe) excels in terms of photon radiation absorption properties and outperforms silicon (Si) in this respect, the crystal growth, characterization and processing into a radiation detector is much more complicated. Additionally, large concentrations of extended crystallographic defects, such as grain boundaries, twins, and tellurium (Te) inclusions, vary from crystal to crystal and can reduce the spectroscopic performance of the processed detector. A quality assessment of the material prior to the complex fabrication process is therefore crucial. To locate the Te-defects, we scan the crystals with infrared microscopy (IRM) in different layers, obtaining a 3D view of the defect distribution. This provides us with important information on the defect density and locations of Te inclusions, and thus a handle to assess the quality of the material. For the classification of defects in the large amount of IRM image data, a convolutional neural network is employed. From the post-processed and analysed IRM data, 3D defect maps of the CdTe crystals are created, which make different patterns of defect agglomerations inside the crystals visible. In total, more than 100 crystals were scanned with the current IRM setup. In this paper, we compare two crystal batches, each consisting of 12 samples. We find significant differences in the defect distributions of the crystals.

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Multispectral photon-counting for medical imaging and beam characterization

Cited by 5 publications

References 25 publications

Quality assessment of Cadmium Telluride as a detector material for multispectral medical imaging

Quality assessment of Cadmium Telluride as a detector material for multispectral medical imaging

Quality assessment of cadmium telluride as a detector material for multispectral medical imaging

Employing infrared microscopy (IRM) in combination with a pre-trained neural network to visualise and analyse the defect distribution in Cadmium Telluride crystals

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