Jacob D Aubrey, Emmett P Perkinson, Ge Wang, Peter J Bonitatibus
{"title":"Metal artifact reduction and contrast agent performance as a function of source spectral shape.","authors":"Jacob D Aubrey, Emmett P Perkinson, Ge Wang, Peter J Bonitatibus","doi":"10.1088/1361-6560/ae0be9","DOIUrl":null,"url":null,"abstract":"<p><p><i>Objective.</i>Empirically map the x-ray source of a Medipix All Resolution Scanner (MARS) photon counting CT (PCCT) with Cu and Sn pre-filters, assess metal artifact reduction (MAR) capabilities of these pre-filters, and measure pre-filtration impact on contrast performance (CP) of FDA approved iopromide and experimental tantalum oxide nanoparticles (TaO<i><sub>x</sub></i>NPs).<i>Approach.</i>The x-ray source of a MARS-PCCT system was empirically mapped with no pre-filtration, seven Cu filters (0.3-2.1 mm), and seven Sn filters (0.15-1.05 mm). A phantom with inserts containing water, lipid, iopromide, TaO<i><sub>x</sub></i>NPs, and metal was scanned with no pre-filtration and Cu and Sn pre-filters. Insert noise, signal, contrast-to-pooled-noise ratio (CPNR), and a fast Fourier transform artifact metric (FFTAM) were calculated for each filter to quantify MAR and CP.<i>Main results.</i>Thick filters for Cu and Sn shifted mean energy of the unfiltered x-ray source (47.9 keV) by 19.2 and 23.4 keV, respectively. Thick filtration, 2.1 mm Cu and 0.6 mm Sn, greatly reduced noise (up to 74%) and FFTAM (up to 71%) for all inserts and energy bins. Thin filtration, 0.3 mm Cu and 0.15 mm Sn, also reduced noise (up to 47%) and FFTAM (up to 41%). In most cases, iopromide lost significant contrast (up to 50%). TaO<i><sub>x</sub></i>NPs also lost contrast, though to a lesser extent (up to 38%). Pre-filtration improved image efficacy (i.e. CPNR), especially for TaO<i><sub>x</sub></i>(up to 61%).<i>Significance.</i>By empirically mapping the source spectrum of a MARS-PCCT system with pre-filters, valuable information was gathered about photon flux distribution and detector artifacts; these findings will prove insightful for applications such as energy binning for effective material decomposition. Furthermore, this information will potentially guide clinical MAR development, most notably for the MARS Extremity 5 × 120 recently deployed for first-in-human trials. Lastly, TaO<i><sub>x</sub></i>NPs were shown to be more compatible than iopromide with spectral shaping.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4000,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics in medicine and biology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1088/1361-6560/ae0be9","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, BIOMEDICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Objective.Empirically map the x-ray source of a Medipix All Resolution Scanner (MARS) photon counting CT (PCCT) with Cu and Sn pre-filters, assess metal artifact reduction (MAR) capabilities of these pre-filters, and measure pre-filtration impact on contrast performance (CP) of FDA approved iopromide and experimental tantalum oxide nanoparticles (TaOxNPs).Approach.The x-ray source of a MARS-PCCT system was empirically mapped with no pre-filtration, seven Cu filters (0.3-2.1 mm), and seven Sn filters (0.15-1.05 mm). A phantom with inserts containing water, lipid, iopromide, TaOxNPs, and metal was scanned with no pre-filtration and Cu and Sn pre-filters. Insert noise, signal, contrast-to-pooled-noise ratio (CPNR), and a fast Fourier transform artifact metric (FFTAM) were calculated for each filter to quantify MAR and CP.Main results.Thick filters for Cu and Sn shifted mean energy of the unfiltered x-ray source (47.9 keV) by 19.2 and 23.4 keV, respectively. Thick filtration, 2.1 mm Cu and 0.6 mm Sn, greatly reduced noise (up to 74%) and FFTAM (up to 71%) for all inserts and energy bins. Thin filtration, 0.3 mm Cu and 0.15 mm Sn, also reduced noise (up to 47%) and FFTAM (up to 41%). In most cases, iopromide lost significant contrast (up to 50%). TaOxNPs also lost contrast, though to a lesser extent (up to 38%). Pre-filtration improved image efficacy (i.e. CPNR), especially for TaOx(up to 61%).Significance.By empirically mapping the source spectrum of a MARS-PCCT system with pre-filters, valuable information was gathered about photon flux distribution and detector artifacts; these findings will prove insightful for applications such as energy binning for effective material decomposition. Furthermore, this information will potentially guide clinical MAR development, most notably for the MARS Extremity 5 × 120 recently deployed for first-in-human trials. Lastly, TaOxNPs were shown to be more compatible than iopromide with spectral shaping.
期刊介绍:
The development and application of theoretical, computational and experimental physics to medicine, physiology and biology. Topics covered are: therapy physics (including ionizing and non-ionizing radiation); biomedical imaging (e.g. x-ray, magnetic resonance, ultrasound, optical and nuclear imaging); image-guided interventions; image reconstruction and analysis (including kinetic modelling); artificial intelligence in biomedical physics and analysis; nanoparticles in imaging and therapy; radiobiology; radiation protection and patient dose monitoring; radiation dosimetry