J Korean Soc Ther Radiol Oncol.  2010 Dec;28(4):224-230. 10.3857/jkstro.2010.28.4.224.

Evaluation of Scatter Reduction Effect of the Aft-Multiple-Slit (AMS) System Using MC Simulation

• Chang J
• Suh TS
• Jang DY
• Jang HS
• Kim S

• KMID: 1460140
• DOI: http://doi.org/10.3857/jkstro.2010.28.4.224

Abstract

PURPOSE
We designed the aft-multiple-slit (AMS) system to reduce scatter in cone-beam computed tomography (CBCT). As a preliminary study, we performed a Monte Carlo N-Particle Transport Code (MCNP) simulation to verify the effectiveness of this system.
MATERIALS AND METHODS
The MCNPX code was used to build the AMS geometry. An AMS is an equi-angled arc to consider beam divergence. The scatter-reduced projection images were compared with the primary images only and the primary plus scatter radiation images with and without AMS to evaluate the effectiveness of scatter reduction. To obtain the full 2 dimensional (2D) projection image, the whole AMS system was moved to obtain closed septa of the AMS after the first image acquisition.
RESULTS
The primary radiation with and without AMS is identical to all the slit widths, but the profiles of the primary plus scattered radiation varied according to the slit widths in the 2D projection image. The average scatter reduction factors were 29%, 15%, 9%, and 8% when the slit widths were 5 mm, 10 mm, 15 mm, and 20 mm, respectively.
CONCLUSION
We have evaluated the scatter reduction effect of the AMS in CBCT imaging using the Monte Carlo (MC) simulations. A preliminary study based on the MCNP simulations showed a mount of scatter reduction with the proposed system.

Keyword

Aft-multiple-slit (AMS); Scatter reduction; Cone-beam CT (BCT)

MeSH Terms

Cone-Beam Computed Tomography