طراحي و ساخت يك فانتوم شبه ACR ، جهت استفاده در آزمون هاي كنترل كيفي دستگاه تصويربرداري ام آر آي

Design an‎d Fabrication of a Semi-ACR Phantom for Quality Control Tests of MRI Imaging System

مهندسي پزشكي

Magnetic Resonance Imaging (MRI) is one of the most accurate an‎d safest diagnostic modalities in medicine, an‎d its optimal performance depends on the regular implementation of quality control (QC) tests. The ACR stan‎dard phantom is considered the most reliable tool for eva‎luating these tests; however, its high cost an‎d complete dependence on imports have limited its widespread use in many imaging centers across the country. This limitation can reduce the frequency of periodic QC assessments, degrade image quality, an‎d increase the likelihood of diagnostic errors. In this study, an ACR like QC phantom was designed an‎d fabricated using plexiglass (PMMA) sheets an‎d MRI compatible filling materials. The design was based on the dimensions an‎d internal structure of the stan‎dard ACR phantom, an‎d the internal components—including the slice thickness wedge, resolution plates, low contrast plates, an‎d uniformity chamber—were reproduced according to QC test requirements. The fabrication process involved precise CNC cutting, layered assembly, complete sealing, an‎d geometric calibration. The final phantom was eva‎luated in three MRI centers using different scanners, an‎d the quantitative results were compared with those obtained from the original ACR phantom. The findings demonstrated that the designed phantom achieved approximately 97% equivalence to the stan‎dard ACR phantom in terms of geometric accuracy, uniformity, slice thickness accuracy, resolution, an‎d signal to noise ratio. The observed differences were within the acceptable limits of QC stan‎dards an‎d did not affect clinical applicability. Moreover, the production cost of the domestic phantom is nearly one tenth of the imported model, an‎d mass production is feasible. Additionally, the modular structure, customizability, use of locally available materials, an‎d potential for developing more specialized versions provide the capability to transform this phantom into a patentable domestic product suitable for the medical equipment market. These features can pave the way for establishing a national stan‎dard in MRI quality control an‎d reducing dependence on imported equipment. Keywords: MRI Quality Control, ACR Phantom, Indigenous Phantom, PMMA, Geometric Accuracy, Image Uniformity

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