Effects of radiation dose level on calcification visibility in cone beam breast CT: A preliminary study

Chao Jen Lai*, Chris C. Shaw, Mustafa C. Altunbas, Yang Meng, Lingyun Chen, Shu Ju Tu, Tianpeng Wang, Xinming Liu, Wei T. Yang, Gary J. Whitman

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

To investigate how the radiation dose level affects the detection of microcalcifications (MCs) in cone beam breast CT (CBCT), simulated MCs were embedded in simulated breast tissue and imaged with an experimental CBCT system. The system employs a 30 × 40 cm2 a-Si/CsI based flat panel detector with a pixel size of 194 microns. Three 5 × 5 clusters of simulated calcifications (212-224, 250-280, and 300-355 μm) were embedded in a stack of 11 cm diameter lunch meat and positioned at the center of each slice of lunch meat. 300 projection images over 360 degrees were acquired in the non-binning mode at various dose levels (4.2, 6, 12, 18, and 24 mGy) three times, and were reconstructed with the Feldkamp algorithm. After that, 767 × 757 × 9 volume data were extracted from the fifteen reconstructed images for each size group, resulting in 45 CBCT MC phantom images. An observer experiment was performed by counting the number of visible MCs for each MC phantom image. The phantom images were displayed on a review workstation with a 1600 × 1200 CRT monitor and reviewed by six readers independently. The order of the images was randomized for each reader. The ratios of the visible MCs were averaged over all readers and plotted as a function of the dose level. The CNR was calculated for each MC size and each doe level as well. The results showed that the performance of the reconstructed images acquired with 4.2 mGy was similar to the images acquired with 6 mGy, and the images acquired with 18 mGy performed similarly to those acquired with 24 mGy.

Original languageEnglish
Title of host publicationMedical Imaging 2006
Subtitle of host publicationPhysics of Medical Imaging
DOIs
StatePublished - 2006
Externally publishedYes
EventMedical Imaging 2006: Physics of Medical Imaging - San Diego, CA, United States
Duration: 12 02 200616 02 2006

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume6142 II
ISSN (Print)1605-7422

Conference

ConferenceMedical Imaging 2006: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego, CA
Period12/02/0616/02/06

Keywords

  • Cone-beam computed tomography
  • Flat-panel detector
  • Isocenter dose
  • Microcalcifications

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