Investigation of the Partial Volume Effect in Pre-Dosimetry of Liver Tumors for 90Y Radioembolization: A Phantom Study.

IF 1.1 Q4 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING
Ayşe Dilaver Akar, Nami Yeyin, Sinem Akyol, Özge Demir, Eylem Gülce Çoker, Mustafa Demir
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引用次数: 0

Abstract

Objectives: Yttrium-90 (90Y) radioembolization has become increasingly important in the treatment of liver tumors. This study aims to experimentally determine the extent to which small liver tumors are affected by the partial volume effect (PVE) in single photon emission computed tomography/computed tomography (SPECT/CT) scintigraphy using technetium-99m-macroaggregated albumin (Tc-99m-MAA), and to investigate the impact of PVE on tumor dosimetry and image quality.

Methods: In this experimental study, a custom-designed liver phantom containing four tumor mimics with diameters of 1 cm, 2 cm, 3 cm, and 5 cm was used. The tumor and liver parenchyma volumes were filled with Tc-99m at a ratio of 4.86: 1. The phantom was imaged in a water tank using SPECT/CT according to standard clinical protocols. Volumetric regions of interest were drawn for each lesion and tumor volumes, contrast values (C), contrast to noise ratios (CNR), and absorbed tumor doses were calculated from the counts obtained. Since this study does not involve live subjects and was conducted solely on a phantom model, ethical approval, informed consent, and consent forms are not required for this study.

Results: Tumor diameters measured on SPECT/CT images matched those obtained from both CT images and the actual dimensions. The contrast values calculated from the SPECT/CT images for lesions with diameters of 2 cm and 5 cm were 2.03 and 3.89, respectively. Similarly, the corresponding CNR values were 8.64 and 21.07. Tumor-to-normal tissue ratios were 2.03 and 3.89 for the 2 cm and 5 cm lesions, respectively. For the 2 cm lesion, the actual and SPECT/CT-derived absorbed doses were 15.3 Gy and 7.87 Gy, respectively. For the 5 cm lesion, these values were 15.4 Gy and 13.38 Gy, respectively. the absorbed tumor doses significantly decreased as tumor diameter decreased due to the influence of PVE.

Conclusion: Tumors smaller than 2 cm in diameter were markedly affected by the PVE. Considering the influence of PVE, or applying appropriate corrections in dosimetric calculations, is of critical importance for improving the accuracy of dosimetry results.

肝肿瘤90Y放射栓塞前剂量测定部分体积效应的研究:一项虚幻研究。
目的:90钇(90Y)放射栓塞在肝脏肿瘤的治疗中越来越重要。本研究旨在通过实验确定在单光子发射计算机断层扫描/计算机断层扫描(SPECT/CT)中使用锝-99m-巨聚集白蛋白(Tc-99m-MAA)的部分体积效应(PVE)对肝脏小肿瘤的影响程度,并探讨PVE对肿瘤剂量学和图像质量的影响。方法:在本实验研究中,采用定制设计的肝模体,其中包含4个直径分别为1cm、2cm、3cm和5cm的肿瘤模拟物。肿瘤和肝实质体积以4.86:1的比例充满Tc-99m。根据标准临床方案,在水箱中使用SPECT/CT对幻体进行成像。为每个病变绘制感兴趣的体积区域,并根据所获得的计数计算肿瘤体积、对比值(C)、噪声对比比(CNR)和吸收肿瘤剂量。由于本研究不涉及活体受试者,并且仅在虚拟模型上进行,因此本研究不需要伦理批准、知情同意和同意书。结果:SPECT/CT图像测量的肿瘤直径与CT图像和实际尺寸相匹配。对于直径为2 cm和5 cm的病变,SPECT/CT图像的对比值分别为2.03和3.89。相应的CNR值分别为8.64和21.07。2 cm和5 cm病变的肿瘤与正常组织的比值分别为2.03和3.89。对于2 cm病变,实际和SPECT/ ct衍生的吸收剂量分别为15.3 Gy和7.87 Gy。对于5cm病变,这些值分别为15.4 Gy和13.38 Gy。由于PVE的影响,肿瘤吸收剂量随肿瘤直径的减小而显著降低。结论:PVE对直径小于2cm的肿瘤有明显影响。考虑PVE的影响,或在剂量学计算中应用适当的校正,对于提高剂量学结果的准确性至关重要。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Molecular Imaging and Radionuclide Therapy
Molecular Imaging and Radionuclide Therapy RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING-
CiteScore
1.30
自引率
0.00%
发文量
50
期刊介绍: Molecular Imaging and Radionuclide Therapy (Mol Imaging Radionucl Ther, MIRT) is publishes original research articles, invited reviews, editorials, short communications, letters, consensus statements, guidelines and case reports with a literature review on the topic, in the field of molecular imaging, multimodality imaging, nuclear medicine, radionuclide therapy, radiopharmacy, medical physics, dosimetry and radiobiology.
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