SU-E-I-40: Phantom Research On Monochromatic Images Taken by Dual CBCT with Multiple Energy Sets

Authors

  • Gao R,

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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  • Wang H,

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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  • Zhang Y,

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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  • Mao R,

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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  • Ren L,

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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  • Yin F

    1. Duke University, Durham, NC - North Carolina
    2. Shandong University, Jinan, Shandong
    3. The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan
    4. Duke University Medical Center, Durham, NC
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Abstract

Purpose:

To evaluate the quality of monochromatic images at the same virtual monochromatic energy using dual cone-beam computed tomography (CBCT) with either kV/kV or MV/kV or MV/MV energy sets.

Methods:

CT images of Catphan 504 phantom were acquired using four different KV and MV settings: 80kV, 140kV, 4MV, 6MV. Three sets of monochromatic images were calculated: 80kV-140kV, 140kV-4MV and 4MV-6MV. Each set of CBCT images were reconstructed from the same selected virtual monochromatic energy of 1MeV. Contrast-to-Noise Ratios (CNRs) were calculated and compared between each pair of images with different energy sets.

Results:

Between kV/MV and MV/MV images, the CNRs are comparable for all inserts. However, differences of CNRs were observed between the kV/kV and kV/MV images. Delrin's CNR ratio between kV/kV image and kV/MV image is 1.634. LDPE's (Low-Density Polyethylene) CNR ratio between kV/kV and kV/MV images is 0.509. Polystyrene's CNR ratio between kV/kV image and kV/MV image is 2.219.

Conclusion:

Preliminary results indicated that the CNRs calculated from CBCT images reconstructed from either kV/MV projections or MV/MV projections for the same selected virtual monochromatic energy may be comparable.

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