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Demirtaş CK, Can M, Karadeniz Ö, Çilengiroğlu ÖV, Ertay T, Kaya GÇ. Energy window optimization in bremsstrahlung imaging after Yttrium-90 microsphere therapy. Biomed Phys Eng Express 2024; 10:025028. [PMID: 38306962 DOI: 10.1088/2057-1976/ad25ba] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/02/2024] [Indexed: 02/04/2024]
Abstract
In imaging of Yttrium-90 patients treated hepatic primary and metastatic cancers, bremsstrahlung photons produced in a wide energy range is used. However, the image quality depends on acquisition energy window. This research aimed energy window optimization for Yttrium-90 bremsstrahlung imaging and 48 patients with various types of cancer received radioembolization therapy were investigated. Patients were imaged using a GE Healthcare Optima NM/CT 640 series gamma camera system with a medium energy general-purpose (MEGP) collimator and planar images were acquired with 8 different energy windows in the 55-400 keV energy range. The data set, formed with the % FOV, contrast, and spatial resolution of image quality parameters calculated from these images, was statistically examined with ANOVA and Tukey tests. According to the visual evaluations and ANOVA/Tukey test results, it was statistically concluded that energy window of 90-110 keV is the optimal energy window while 60-400 keV energy ranges show the lowest image quality for Y-90 bremsstrahlung imaging.
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Affiliation(s)
- C Kayaş Demirtaş
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
| | - M Can
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Program of Nuclear Medicine Techniques, Vocational School of Health Services, Dokuz Eylül University, 35330, İnciralti, İzmir, Turkey
| | - Ö Karadeniz
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Physics, Faculty of Sciences, Dokuz Eylül University, 35390, Tınaztepe, Izmir, Turkey
| | - Ö Vupa Çilengiroğlu
- Department of Statistics, Faculty of Sciences, Dokuz Eylül University, 35390, Tınaztepe, Izmir, Turkey
| | - T Ertay
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, Inciraltı, Izmir, Turkey
| | - G Çapa Kaya
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, Inciraltı, Izmir, Turkey
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Deidda D, Denis-Bacelar AM, Fenwick AJ, Ferreira KM, Heetun W, Hutton BF, Robinson AP, Scuffham J, Thielemans K. Hybrid kernelised expectation maximisation for Bremsstrahlung SPECT reconstruction in SIRT with 90Y micro-spheres. EJNMMI Phys 2022; 9:25. [PMID: 35377085 PMCID: PMC8980141 DOI: 10.1186/s40658-022-00452-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/16/2022] [Indexed: 11/16/2022] Open
Abstract
Background Selective internal radiation therapy with Yttrium-90 microspheres is an effective therapy for liver cancer and liver metastases. Yttrium-90 is mainly a high-energy beta particle emitter. These beta particles emit Bremsstrahlung radiation during their interaction with tissue making post-therapy imaging of the radioactivity distribution feasible. Nevertheless, image quality and quantification is difficult due to the continuous energy spectrum which makes resolution modelling, attenuation and scatter estimation challenging and therefore the dosimetry quantification is inaccurate. As a consequence a reconstruction algorithm able to improve resolution could be beneficial. Methods In this study, the hybrid kernelised expectation maximisation (HKEM) is used to improve resolution and contrast and reduce noise, in addition a modified HKEM called frozen HKEM (FHKEM) is investigated to further reduce noise. The iterative part of the FHKEM kernel was frozen at the 72nd sub-iteration. When using ordered subsets algorithms the data is divided in smaller subsets and the smallest algorithm iterative step is called sub-iteration. A NEMA phantom with spherical inserts was used for the optimisation and validation of the algorithm, and data from 5 patients treated with Selective internal radiation therapy were used as proof of clinical relevance of the method. Results The results suggest a maximum improvement of 56% for region of interest mean recovery coefficient at fixed coefficient of variation and better identification of the hot volumes in the NEMA phantom. Similar improvements were achieved with patient data, showing 47% mean value improvement over the gold standard used in hospitals. Conclusions Such quantitative improvements could facilitate improved dosimetry calculations with SPECT when treating patients with Selective internal radiation therapy, as well as provide a more visible position of the cancerous lesions in the liver.
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Affiliation(s)
- Daniel Deidda
- National Physical Laboratory, Teddington, UK. .,Institute of Nuclear Medicine, University College London, London, UK.
| | | | | | | | | | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, London, UK
| | - Andrew P Robinson
- National Physical Laboratory, Teddington, UK.,Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK.,The University of Manchester, Manchester, UK
| | - James Scuffham
- National Physical Laboratory, Teddington, UK.,Department of Medical Physics, Royal Surrey NHS Foundation Trust, Guildford, UK
| | - Kris Thielemans
- Institute of Nuclear Medicine, University College London, London, UK
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Role of nanoparticles in transarterial radioembolization with glass microspheres. Ann Nucl Med 2022; 36:479-487. [PMID: 35199286 DOI: 10.1007/s12149-022-01727-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/06/2022] [Indexed: 11/01/2022]
Abstract
OBJECTIVE Transarterial Radioembolization (TARE) with 90Y-loaded glass microspheres is a locoregional treatment option for Hepatocellular Carcinoma (HCC). Post-treatment 90Y bremsstrahlung imaging using Single-Photon Emission Tomography (SPECT) is currently a gold-standard imaging modality for quantifying the delivered dose. However, the nature of bremsstrahlung photons causes difficulty for dose estimation using SPECT imaging. This work aimed to investigate the possibility of using glass microspheres loaded with 90Y and Nanoparticles (NPs) to improve the quantification of delivered doses. METHODS The Monte Carlo codes were used to simulate the post-TARE 90Y planar imaging. Planar images from bremsstrahlung photons and characteristic X-rays are acquired when 0, 1.2 mol/L, 2.4 mol/L, and 4.8 mol/L of Gold (Au), Hafnium (Hf), and Gadolinium (Gd) NPs are incorporated into the glass microspheres. We evaluated the quality of acquired images by calculating sensitivity and Signal-to-Background Ratio (SBR). Therapeutic effects of NPs were evaluated by calculation of Dose Enhancement Ratio (DER) in tumoral and non-tumoral liver tissues. RESULTS The in silico results showed that the sensitivity values of bremsstrahlung and characteristic X-ray planar images increased significantly as the NPs concentration increased in the glass microspheres. The SBR values decreased as the NPs concentration increased for the bremsstrahlung planar images. In contrast, the SBR values increased for the characteristic X-ray planar images when Hf and Gd were incorporated into the glass microspheres. The DER values decreased in the tumoral and non-tumoral liver tissues as the NPs concentration increased. The maximum dose reduction was observed at the NPs concentration of 4.8 mol/L (≈ 7%). CONCLUSIONS The incorporation of Au, Hf, and Gd NPs into the glass microspheres improved the quality and quantity of post-TARE planar images. Also, treatment efficiency was decreased significantly at NPs concentration > 4.8 mol/L.
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