open access

Vol 22, No 2 (2019)
Original articles
Published online: 2019-07-23
Submitted: 2018-06-10
Accepted: 2019-06-11
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Evaluation the effect of different collimators and energy window on Y-90 bremsstrahlung SPECT imaging by SIMIND Monte Carlo program

Payvand Taherparvar, Nazila Shahmari
DOI: 10.5603/NMR.a2019.0016
·
Pubmed: 31482556
·
Nucl. Med. Rev 2019;22(2):45-55.

open access

Vol 22, No 2 (2019)
Original articles
Published online: 2019-07-23
Submitted: 2018-06-10
Accepted: 2019-06-11

Abstract

BACKGROUND: Recently, the treatment efficiency of Yttrium 90 (Y-90) and providing reliable estimates of activity by single photon emission computed tomography (SPECT) imaging of bremsstrahlung radiation released during beta therapy have been evaluated. In the Y-90 bremsstrahlung SPECT imaging, the resulting energy spectrum is very complex and continuous, which creates many difficulties in the imaging protocol and image reconstruction. Furthermore, image quality and quantitative accuracy in the bremsstrahlung SPECT imaging are affected by collimator penetration and scatter. So, the collimator type and its geometry have impressive effects on the spatial resolution, system sensitivity and image contrast.

MATERIAL AND METHODS: Hereby, in this paper, we evaluated the effect of the energy window (three energy windows: 60 to 160 keV, 160 to 400 keV, and 60 to 400 keV) and the commercial parallel-hole collimators with different geometric parameters on the Y-90 bremsstrahlung spectrum and the image quality of the liver tumors based on criteria such as system sensitivity and image contrast. SIMIND Monte Carlo simulation code was used to generate the Y-90 bremsstrahlung SPECT images of the liver tumor with different diameters: 1.36, 2.04, 2.72, 3.4, 4.08, and 4.76 cm by use of the digital Zubal phantom. Furthermore, the tumor size was estimated by evaluating pixel intensity profile on the line drawn through the activity distribution image.

RESULTS: Our results showed that the collimator choice and energy window setting in the bremsstrahlung SPECT imaging have significant effects on the image quality and tumor size estimation. Optimal image quality could be acquired by the energy window of 60 to 400 keV and the SPECT system equipped with a Medium-Energy General-Purpose (MEGP) collimator of Millennium VG Kameran (GV) Company. Moreover, the estimation of distribution size was close to the actual value for tumor sizes larger than 2.04 cm, especially by using the SPECT system equipped with the GV-MEGP collimator in the wide energy window.

CONCLUSIONS: We found an optimal collimator to be more appropriate for improving the imaging quality of Y-90 bremsstrahlung photons, which can be used for reliable activity distribution estimates after radiation therapy.

Abstract

BACKGROUND: Recently, the treatment efficiency of Yttrium 90 (Y-90) and providing reliable estimates of activity by single photon emission computed tomography (SPECT) imaging of bremsstrahlung radiation released during beta therapy have been evaluated. In the Y-90 bremsstrahlung SPECT imaging, the resulting energy spectrum is very complex and continuous, which creates many difficulties in the imaging protocol and image reconstruction. Furthermore, image quality and quantitative accuracy in the bremsstrahlung SPECT imaging are affected by collimator penetration and scatter. So, the collimator type and its geometry have impressive effects on the spatial resolution, system sensitivity and image contrast.

MATERIAL AND METHODS: Hereby, in this paper, we evaluated the effect of the energy window (three energy windows: 60 to 160 keV, 160 to 400 keV, and 60 to 400 keV) and the commercial parallel-hole collimators with different geometric parameters on the Y-90 bremsstrahlung spectrum and the image quality of the liver tumors based on criteria such as system sensitivity and image contrast. SIMIND Monte Carlo simulation code was used to generate the Y-90 bremsstrahlung SPECT images of the liver tumor with different diameters: 1.36, 2.04, 2.72, 3.4, 4.08, and 4.76 cm by use of the digital Zubal phantom. Furthermore, the tumor size was estimated by evaluating pixel intensity profile on the line drawn through the activity distribution image.

RESULTS: Our results showed that the collimator choice and energy window setting in the bremsstrahlung SPECT imaging have significant effects on the image quality and tumor size estimation. Optimal image quality could be acquired by the energy window of 60 to 400 keV and the SPECT system equipped with a Medium-Energy General-Purpose (MEGP) collimator of Millennium VG Kameran (GV) Company. Moreover, the estimation of distribution size was close to the actual value for tumor sizes larger than 2.04 cm, especially by using the SPECT system equipped with the GV-MEGP collimator in the wide energy window.

CONCLUSIONS: We found an optimal collimator to be more appropriate for improving the imaging quality of Y-90 bremsstrahlung photons, which can be used for reliable activity distribution estimates after radiation therapy.

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Keywords

Yttrium-90; SPECT; energy window; parallel-hole collimators; image contrast; bremsstrahlung; Monte Carlo simulation

About this article
Title

Evaluation the effect of different collimators and energy window on Y-90 bremsstrahlung SPECT imaging by SIMIND Monte Carlo program

Journal

Nuclear Medicine Review

Issue

Vol 22, No 2 (2019)

Pages

45-55

Published online

2019-07-23

DOI

10.5603/NMR.a2019.0016

Pubmed

31482556

Bibliographic record

Nucl. Med. Rev 2019;22(2):45-55.

Keywords

Yttrium-90
SPECT
energy window
parallel-hole collimators
image contrast
bremsstrahlung
Monte Carlo simulation

Authors

Payvand Taherparvar
Nazila Shahmari

References (18)
  1. Ahmadzadehfar H, Biersack HJ, Ezziddin S. Radioembolization of liver tumors with yttrium-90 microspheres. Semin Nucl Med. 2010; 40(2): 105–121.
  2. Rong X, Frey EC. A collimator optimization method for quantitative imaging: application to Y-90 bremsstrahlung SPECT. Med Phys. 2013; 40(8): 082504.
  3. Minarik D, Sjögreen Gleisner K, Ljungberg M. Evaluation of quantitative (90)Y SPECT based on experimental phantom studies. Phys Med Biol. 2008; 53(20): 5689–5703.
  4. Rong X, Du Y, Ljungberg M, et al. Development and evaluation of an improved quantitative (90)Y bremsstrahlung SPECT method. Med Phys. 2012; 39(5): 2346–2358.
  5. Bonutti F, Avolio M, Magro G, et al. Optimization of the image contrast in SPECT-CT bremsstrahlung imaging for Selective Internal Radiation Therapy of liver malignancies with Y-90 microspheres. arXiv:1509.08857 [physics.med-ph]. 2015; 1–13. ArXiv:1509.08857.
  6. Chery SR, Sorenson JA, Phelps ME. Physics in Nuclear Medicine. Elsevier/ Saunders Philadelphia. 2012.
  7. Roshan HR, Mahmoudian B, Gharepapagh E, et al. Collimator and energy window optimization for ⁹⁰Y bremsstrahlung SPECT imaging: A SIMIND Monte Carlo study. Appl Radiat Isot. 2016; 108: 124–128.
  8. Walrand S, Hesse M, Wojcik R, et al. Optimal design of anger camera for bremsstrahlung imaging: monte carlo evaluation. Front Oncol. 2014; 4: 149.
  9. Förnvik D, Zackrisson S, Ljungberg O, et al. Breast tomosynthesis: Accuracy of tumor measurement compared with digital mammography and ultrasonography. Acta Radiol. 2010; 51(3): 240–247.
  10. Rong X, Du Y, Frey EC. A method for energy window optimization for quantitative tasks that includes the effects of model-mismatch on bias: application to Y-90 bremsstrahlung SPECT imaging. Phys Med Biol. 2012; 57(12): 3711–3725.
  11. Roshan HR, Azarm A, Mahmoudian B, et al. Advances in SPECT for Optimizing the Liver Tumors Radioembolization Using Yttrium-90 Microspheres. World J Nucl Med. 2015; 14(2): 75–80.
  12. Gonzalez-Guindalini FD, Botelho MPF, Harmath CB, et al. Assessment of liver tumor response to therapy: role of quantitative imaging. Radiographics. 2013; 33(6): 1781–1800.
  13. Hruska CB, O'Connor MK. Quantification of lesion size, depth, and uptake using a dual-head molecular breast imaging system. Med Phys. 2008; 35(4): 1365–1376.
  14. Tan YC, Chiu WK, Rajic N. Quantitative Defect Detection on the Underside of a Flat Plate Using Mobile Thermal Scanning. Procedia Engineering. 2017; 188: 493–498.
  15. Ljungberg M. The SIMIND Monte Carlo program. Monte Carlo Calculations in Nuclear Medicine: Applications in Diagnostic Imaging. CRC Press, Boca Raton U.S.A. 2012.
  16. DeWerd LA. The phantoms of medical and health physics. Kissick M (ed.), Springer 2014.
  17. MATLAB. version 8.1 (R2013a). Natick, Massachusetts: The MathWorks Inc.; 2013.
  18. Rong X, Ghaly M, Frey EC. Optimization of energy window for 90Y bremsstrahlung SPECT imaging for detection tasks using the ideal observer with model-mismatch. Med Phys. 2013; 40(6): 062502.

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