SU‐FF‐I‐20: Visibility of Simulated Microcalcifications with An ASi/aSe Flat Panel Detector Based Cone Beam CT System

Y. Shen, S. Ge, L. Chen, Y. Yi, Z. You, T. Han, Y. Zhong, X. Liu, C. Lai, T. Wang, C. Shaw

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To investigate the visibility of microcalcifications (MCs) with an aSi/aSe flat panel detector (FPD14, Anrad Corporation) based cone beam CT (CBCT) system. Method and materials: A bench top experimental CBCT system was configured for breast imaging and used to image a breast phantom with embedded simulated MCs of various sizes. A paraffin cylinder with a diameter of 135 mm and a height of 40 mm was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125 to 425 μm in size, were used to simulate the microcalcifications. 25 MCs from same size group were arranged into a 5 × 5 cluster and embedded at the center of a 15 mm diameter paraffin rod to make an MC insert, which may be inserted into a hole at the center of the breast phantom for imaging. The breast phantom with MCs was scanned at various exposure levels. 300 projection images were acquired over 360° and reconstructed with Feldkamp's backprojection algorithm using a ramp filter. The images were reviewed by 6 readers. The ratios of visible MCs, averaged over all readers, were plotted as the function of the square root of measured dose level and image signal‐to‐noise ratio (SNR). Results: It was found that 90% visibility was achieved for 224 – 250 μm calcifications at an SNR of 16.8 or an isocenter dose of 5.2 mGys. 70% visibility was achieved for 224 – 250, 212 – 224, 200 – 212, 180 – 200, 160 – 180, 150 – 160 and 124 – 140 μm calcifications at an SNR of 16.8, 16.8, 25.1, 25.1, 44.5, 44.5 and 52.6, respectively. Conclusions: Percentage of visible MCs increased with the image SNR and isocenter dose. Higher SNRs and isocenter dose are required for imaging smaller MCs.

Original languageEnglish (US)
Number of pages1
JournalMedical Physics
Volume36
Issue number6
DOIs
StatePublished - Jan 1 2009

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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