Allam Ubaidillah, A. R. Fauzia, Adi Teguh Purnomo, N. Nasution, W. Wibowo, S. Pawiro
{"title":"Effect of the Small Field of View and Imaging Parameters to Image Quality and Dose Calculation in Adaptive Radiotherapy","authors":"Allam Ubaidillah, A. R. Fauzia, Adi Teguh Purnomo, N. Nasution, W. Wibowo, S. Pawiro","doi":"10.2478/pjmpe-2023-0014","DOIUrl":null,"url":null,"abstract":"Abstract Background The use of cone beam computed tomography (CBCT) for dose calculation in adaptive radiotherapy has been investigated in many studies. Proper acquisition and reconstruction of preset parameters could improve the accuracy of dose calculation based on CBCT images. This study evaluated the impact of the modified image acquisition and preset reconstruction parameter available in X-Ray Volumetric Imaging (XVI) to improve CBCT image quality and dose calculation accuracy. Materials and methods Calibration curves were generated by scanning the CIRS phantom using CBCT XVI Elekta 5.0.4 and Computed Tomography (CT) Simulator Somatom, which served as CT image reference. Rando and Catphan 503 phantoms were scanned with various acquisition and reconstruction parameters for dose accuracy and image quality tests. The image quality test is uniformity, low contrast visibility, spatial resolution, and geometrical scale test for each image by following the XVI image quality test module. Results Acquisition and reconstruction parameters have an impact on the Hounsfield Unit (HU) value that is used as the HU-Relative Electron Density (RED) calibration curve. The dose difference for all the calibration curves was within 1% and passed the gamma passing rate. Images acquired using 120 kVp, F1 (with Bowtie Filter), and 50 mA (F1-120-50-10) scored the highest Gamma Index (GI) of 98.5%. For the image quality test, it scored 1.20% on the uniformity test, 2.14% on the low contrast visibility test, and 11 lp/cm on the spatial resolution test. However, F1-120-50-10 reconstructed with different reconstructions scored 3.83% and 4 lp/cm in contrast and spatial resolution test, respectively. Conclusion CBCT reconstruction parameters work as a scatter correction. It could improve the dose accuracy and image quality. Nevertheless, without adequate CBCT acquisition protocols, it would produce an image with high uncertainty and cannot be fixed with reconstruction protocols. The F1-120-50-10 protocols generate the highest dose accuracy and image quality.","PeriodicalId":53955,"journal":{"name":"Polish Journal of Medical Physics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polish Journal of Medical Physics and Engineering","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2478/pjmpe-2023-0014","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract Background The use of cone beam computed tomography (CBCT) for dose calculation in adaptive radiotherapy has been investigated in many studies. Proper acquisition and reconstruction of preset parameters could improve the accuracy of dose calculation based on CBCT images. This study evaluated the impact of the modified image acquisition and preset reconstruction parameter available in X-Ray Volumetric Imaging (XVI) to improve CBCT image quality and dose calculation accuracy. Materials and methods Calibration curves were generated by scanning the CIRS phantom using CBCT XVI Elekta 5.0.4 and Computed Tomography (CT) Simulator Somatom, which served as CT image reference. Rando and Catphan 503 phantoms were scanned with various acquisition and reconstruction parameters for dose accuracy and image quality tests. The image quality test is uniformity, low contrast visibility, spatial resolution, and geometrical scale test for each image by following the XVI image quality test module. Results Acquisition and reconstruction parameters have an impact on the Hounsfield Unit (HU) value that is used as the HU-Relative Electron Density (RED) calibration curve. The dose difference for all the calibration curves was within 1% and passed the gamma passing rate. Images acquired using 120 kVp, F1 (with Bowtie Filter), and 50 mA (F1-120-50-10) scored the highest Gamma Index (GI) of 98.5%. For the image quality test, it scored 1.20% on the uniformity test, 2.14% on the low contrast visibility test, and 11 lp/cm on the spatial resolution test. However, F1-120-50-10 reconstructed with different reconstructions scored 3.83% and 4 lp/cm in contrast and spatial resolution test, respectively. Conclusion CBCT reconstruction parameters work as a scatter correction. It could improve the dose accuracy and image quality. Nevertheless, without adequate CBCT acquisition protocols, it would produce an image with high uncertainty and cannot be fixed with reconstruction protocols. The F1-120-50-10 protocols generate the highest dose accuracy and image quality.
摘要背景锥形束计算机断层扫描(CBCT)在适应性放疗中的剂量计算已被许多研究所探讨。对预设参数进行适当的获取和重建,可以提高基于CBCT图像的剂量计算精度。本研究评估了x射线体积成像(XVI)中改进的图像采集和预设重建参数对提高CBCT图像质量和剂量计算精度的影响。材料与方法采用CBCT XVI Elekta 5.0.4和CT模拟器Somatom作为CT图像参考,对CIRS假体进行扫描,生成校正曲线。用不同的采集和重建参数扫描Rando和Catphan 503模型,进行剂量精度和图像质量测试。图像质量测试是按照XVI图像质量测试模块对每张图像进行均匀性、低对比度可见度、空间分辨率和几何尺度测试。结果采集和重建参数对用作相对电子密度(RED)校准曲线的Hounsfield Unit (HU)值有影响。各校正曲线的剂量差值在1%以内,均通过伽玛通过率。使用120 kVp, F1(带领结滤镜)和50 mA (F1-120-50-10)获得的图像的Gamma指数(GI)最高,为98.5%。在图像质量测试中,均匀性测试得分为1.20%,低对比度可见性测试得分为2.14%,空间分辨率测试得分为11 lp/cm。不同重建方式重建的F1-120-50-10在对比度和空间分辨率测试中的得分分别为3.83%和4 lp/cm。结论CBCT重建参数具有散射校正的作用。它可以提高剂量精度和图像质量。然而,如果没有适当的CBCT采集协议,则会产生具有高不确定性的图像,无法用重建协议进行固定。F1-120-50-10方案产生最高剂量精度和图像质量。
期刊介绍:
Polish Journal of Medical Physics and Engineering (PJMPE) (Online ISSN: 1898-0309; Print ISSN: 1425-4689) is an official publication of the Polish Society of Medical Physics. It is a peer-reviewed, open access scientific journal with no publication fees. The issues are published quarterly online. The Journal publishes original contribution in medical physics and biomedical engineering.