Dual Energy Metal Artifact Reduction for Iodine-125 Seed Identification in Postimplant CT after Prostate Brachytherapy

Chiaki Suzuki; Kosuke Matsubara; Yuta Ujihara; Kenta Isogai

doi:10.1093/bjr/tqae225

Dual Energy Metal Artifact Reduction for Iodine-125 Seed Identification in Postimplant CT after Prostate Brachytherapy

Br J Radiol. 2024 Nov 4:tqae225. doi: 10.1093/bjr/tqae225. Online ahead of print.

Authors

Chiaki Suzuki^{1

2}, Kosuke Matsubara³, Yuta Ujihara², Kenta Isogai²

Affiliations

¹ Department of Diagnostic Radiology, Seirei Mikatahara Hospital, Seirei Social Welfare Community, Hamamatsu-city, Shizuoka, JAPAN.
² Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, JAPAN.
³ Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, JAPAN.

PMID: 39495147
DOI: 10.1093/bjr/tqae225

Abstract

Objectives: To assess the metal artifact reductions of dual-energy computed tomography (DECT) high-energy virtual monochromatic images (VMI) combined with the single energy metal artifact reduction (SEMER) (CANON MEDICAL SYSTEMS, Otawara, Japan) processing techniques for iodine (I)-125 seed identification in postimplant computed tomography (CT) after prostate brachytherapy.

Methods: Dual-energy acquisition with fast tube voltage switching was performed on a prostate phantom with simulated seeds and six clinical cases treated with I-125 prostate brachytherapy. The images were retrospectively reconstructed at VMI energy levels of 65-200 keV and with and without SEMAR (SEMAR and non-SEMAR images). To estimate seed swelling, the caliber of iodine-125 seed was calculated as the full width at half maximum. The metal artifacts were evaluated using the artifact index (AI). The dose distributions were calculated and were compared among the high-energy VMI (SEMAR and non-SEMAR images) and low-energy VMI (SEMAR images).

Results: The blooming artifacts decreased at higher energy levels. In addition, the SEMAR process markedly reduced AI, which helped reduce overestimation of high dose ranges in the treatment planning dose map.

Conclusion: The locations and number of iodine-125 seed were clearly identified in the dose distribution map of the treatment planning using 200keV VMI with SEMAR.

Advance in knowledge: The high-energy VMI of the dual energy CT in combination with SEMAR is appropriate for the postimplant planning process of I-125 prostate brachytherapy.