Monte Carlo evaluation of scattering correction methods in <sup>131</sup>I studies using pinhole collimator

Main Article Content

Adlin López Díaz
Sunay Rodríguez Pérez
Angelina Díaz García
Aley Palau San Pedro
Juan Miguel Martín Escuela

Abstract

Scattering is quite important for image activity quantification. In order to study the scattering factors and the efficacy of 3 multiple window energy scatter correction methods during 131I thyroid studies with a pinhole collimator (5 mm hole) a Monte Carlo simulation (MC) was developed. The GAMOS MC code was used to model the gamma camera and the thyroid source geometry. First, to validate the MC gamma camera pinhole-source model, sensibility in air and water of the simulated and measured thyroid phantom geometries were compared. Next, simulations to investigate scattering and the result of triple energy (TEW), Double energy (DW) and Reduced double (RDW) energy windows correction methods were performed for different thyroid sizes and depth thicknesses. The relative discrepancies to MC real event were evaluated. Results: The accuracy of the GAMOS MC model was verified and validated. The image’s scattering contribution was significant, between 27-40 %. The discrepancies between 3 multiple window energy correction method results were significant (between 9-86 %). The Reduce Double Window methods (15%) provide discrepancies of 9-16 %. Conclusions: For the simulated thyroid geometry with pinhole, the RDW (15 %) was the most effective.

Article Details

How to Cite
López Díaz, A., Rodríguez Pérez, S., Díaz García, A., Palau San Pedro, A., & Martín Escuela, J. M. (1). Monte Carlo evaluation of scattering correction methods in <sup>131</sup&gt;I studies using pinhole collimator. Nucleus, (61), 11-15. Retrieved from http://nucleus.cubaenergia.cu/index.php/nucleus/article/view/12
Section
Ciencias Nucleares

References

[1] STOKKEL MP, HANDKIEWIC D, LASSMANN M, et. al. EANM procedure guidelines for therapy of benign thyroid disease. Eur J Nucl Med Mol Imaging. 2010; 37(11): 2218-2228.
[2] MERRILL S, HOROWITZ J, TRAINO AC, et. al. Accuracy and optimal timing of activity measurements in estimating the absorbed dose of radioiodine in the treatment of Graves’ disease. Phys Med Biol. 2011; 56(3): 557-71.
[3] DELOAR HM, WATABE H, AOI T & IIDA H. Evaluation of penetration and scattering components in conventional pinhole SPECT: phantom studies using Monte Carlo simulation. Phys. Med. Biol. 2003; 48(8): 995-1008.
[4] SMITH MF & JASZCZAK J. The effect of gamma ray penetration on angle-dependent sensitivity for pinhole collimation in nuclear medicine. Med. Phys. 1997; 24(11): 1701-9.
[5] ZAIDI H. Quantitative analysis in nuclear medicine imaging. Springer, 2006.
[6] LJUNGBERG M AND STRAND S. Scatter and attenuation corrections in SPECT using density maps and Monte Carlo simulated scatter functions. J Nucl Med. 1990; 31(9): 1560-1567.
[7] ESPAÑA S, HERRAIZ JL, VICENTE E, et. al. PeneloPET, a Monte Carlo PET simulation tool based on PENELOPE: features and validation. Phys Med Biol. 2009; 54(6): 1723-1742.
[8] ALLISON J. Geant4 developments and applications. IEEE Transactions on Nuclear Science. 2006; 53(1): 270 -278.
[9] AMIDE: Amide's a Medical Imaging Data Examiner. AMIDE.exe 0.9.2 [software online]. Disponible en: http://amide.sourceforge.net [May 2013].
[10] GAMOS 2011. User’s Guide [guide online]. Disponible en: http://fismed.ciemat.es/GAMOS/gamos_userguide.php. [January 2013].
[11] NORRGREN K, SVEGBORN S, AREBERG J & MATTSSON S. Accuracy of the quantification of organ activity from planar gamma camera images. Cancer Biother Radiopharm. 2003; 1(18): 125-131.
[12] DEWARAJA YK, LJUNGBERG M, GREEN AJ, et. al. MIRD Pamphlet No. 24: guidelines for quantitative 131I SPECT in dosimetry applications. J Nucl Med. 2013; 54(12): 2182-2188.
[13] DEWARAJA YK, FREY EC, SGOUROS G, et. al. MIRD Pamphlet No. 23: quantitative SPECT for patient-specific 3-dimensional dosimetry in internal radionuclide therapy. J Nucl Med. 2012; 53(8): 1310-1325.
[14] STABIN M. Uncertainties in internal dose calculations for radiopharmaceuticals. J Nucl Med. 2008; 49(5): 853-860.

Most read articles by the same author(s)