Designing a phantom for dose evaluation in multi-slice CT

Samir F Abboud*, Andreu Badal, Stanley H. Stern, Iacovos S. Kyprianou

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Accurately representing radiation dose delivered in MSCT is becoming a concern as the maximum beam width of some modern CT scanners tends to become wider than the 100 mm charge-collection length of the pencil ionization chamber generally used in CT dosimetry. We investigate two alternative methods of dose evaluation in CT scanners. We investigate two alternative approaches for better characterization of CT dose than conventional evaluation of CTD 100-First, we simulate dose profiles and energy deposition in phantoms longer than the typically used 14-15 cm length right-circular cylinders. Second we explore the accuracy and practicality of applying mathematical convolution to a scatter kernel in order to generate dose profiles. A basic requirement for any newly designed phantom is that it be able to capture approximately the same dose as would an infinitely long cylinder, but yet be of a size and weight that a person could easily carry and position. Using the PENELOPE Monte Carlo package, we simulated dose profiles in cylindrical polymethyl methacrylate (PMMA) phantoms of 10, 16, 20, 24 and 32 cm diameter and 15, 30 and 300 cm length. Beam widths were varied from 1 cm to 60 cm. Lengths necessary to include within the dose integrals values associated with the scatter tails as well as with the primary radiation of the profile were then calculated as the full width at five percent of maximum dose. The resulting lengths suggest that to accommodate wide beam widths, phantoms longer than those currently used are necessary. The results also suggest that using a longer phantom is a relatively more accurate approach, while using mathematical convolution is simpler and more practical to implement than using the long phantoms designed according to direct Monte Carlo simulations.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2010
Subtitle of host publicationPhysics of Medical Imaging
EditionPART 2
StatePublished - 2010
EventMedical Imaging 2010: Physics of Medical Imaging - San Diego, CA, United States
Duration: Feb 15 2010Feb 18 2010

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
NumberPART 2
ISSN (Print)1605-7422


ConferenceMedical Imaging 2010: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego, CA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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