Attenuation correction of 111In planar images by use of dual energy, fundamental study by Monte Carlo simulation

Seiji Shirakawa, Masanori Tadokoro, Hiroshi Hashimoto, Tomoya Ushiroda, Hiroshi Toyama

研究成果: Article

抄録

In this study, we devised and evaluated a method for attenuation correction of the hot spot in 111In planar images. By use of the difference in transmittance between two energies (171 and 245 keV), the depth of the hot spot was calculated. Planar images of point sources in a numerical phantom (water) with depths from 0 to 20 cm at 2 cm intervals were prepared by Monte Carlo simulation. From the linear attenuation coefficient of the two energies and the 171/245 keV count ratio-depth relationship, the depth of the point source was calculated, and an attenuation correction was performed. A simulation was made under conditions taking into account both attenuation and scatter (A(+)S(+)) and attenuation alone (A(+)S(−)). The attenuation correction was evaluated with use of corrected and true counts obtained from homogeneous phantoms mimicking attenuation in soft tissue, bone, and the lungs, and heterogeneous phantoms prepared by combining them. In the A(+)S(+) condition, images were affected markedly by scattered photons in all phantoms at depths of 4–8 cm. The errors at depths of 10 cm or greater were within ±10 % in water and within ±6 % in soft tissue. However, the errors were about −30 % in bone and about +70 % in lung, indicating that scatter distributions different from those in water increased the errors. In the A(+)S(−) condition, the errors were within ±5 % in all homogeneous and heterogeneous phantoms, and satisfactory results were obtained. Precise attenuation correction of scatter-corrected planar images was confirmed to be possible with this method.

元の言語English
ページ(範囲)36-45
ページ数10
ジャーナルRadiological Physics and Technology
8
発行部数1
DOI
出版物ステータスPublished - 01-01-2015

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attenuation
Water
Bone and Bones
Lung
simulation
Photons
energy
lungs
point sources
bones
water
attenuation coefficients
transmittance
intervals
photons

All Science Journal Classification (ASJC) codes

  • Radiation
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Radiology Nuclear Medicine and imaging

これを引用

Shirakawa, Seiji ; Tadokoro, Masanori ; Hashimoto, Hiroshi ; Ushiroda, Tomoya ; Toyama, Hiroshi. / Attenuation correction of 111In planar images by use of dual energy, fundamental study by Monte Carlo simulation. :: Radiological Physics and Technology. 2015 ; 巻 8, 番号 1. pp. 36-45.
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abstract = "In this study, we devised and evaluated a method for attenuation correction of the hot spot in 111In planar images. By use of the difference in transmittance between two energies (171 and 245 keV), the depth of the hot spot was calculated. Planar images of point sources in a numerical phantom (water) with depths from 0 to 20 cm at 2 cm intervals were prepared by Monte Carlo simulation. From the linear attenuation coefficient of the two energies and the 171/245 keV count ratio-depth relationship, the depth of the point source was calculated, and an attenuation correction was performed. A simulation was made under conditions taking into account both attenuation and scatter (A(+)S(+)) and attenuation alone (A(+)S(−)). The attenuation correction was evaluated with use of corrected and true counts obtained from homogeneous phantoms mimicking attenuation in soft tissue, bone, and the lungs, and heterogeneous phantoms prepared by combining them. In the A(+)S(+) condition, images were affected markedly by scattered photons in all phantoms at depths of 4–8 cm. The errors at depths of 10 cm or greater were within ±10 {\%} in water and within ±6 {\%} in soft tissue. However, the errors were about −30 {\%} in bone and about +70 {\%} in lung, indicating that scatter distributions different from those in water increased the errors. In the A(+)S(−) condition, the errors were within ±5 {\%} in all homogeneous and heterogeneous phantoms, and satisfactory results were obtained. Precise attenuation correction of scatter-corrected planar images was confirmed to be possible with this method.",
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Attenuation correction of 111In planar images by use of dual energy, fundamental study by Monte Carlo simulation. / Shirakawa, Seiji; Tadokoro, Masanori; Hashimoto, Hiroshi; Ushiroda, Tomoya; Toyama, Hiroshi.

:: Radiological Physics and Technology, 巻 8, 番号 1, 01.01.2015, p. 36-45.

研究成果: Article

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