Hybrid modality dual-energy imaging aggregating complementary advantages of kV-CT and MV-CBCT: concept proposal and clinical validation

Junfeng Qi; Shutong Yu; Zhengkun Dong; Jiang Liu; Juan Deng; Guojian Mei; Chuou Yin; Qiao Li; Tian Li; Shi Wang; Yibao Zhang

doi:10.1088/1361-6560/ad84b1

Hybrid modality dual-energy imaging aggregating complementary advantages of kV-CT and MV-CBCT: concept proposal and clinical validation

Phys Med Biol. 2024 Oct 8. doi: 10.1088/1361-6560/ad84b1. Online ahead of print.

Authors

Junfeng Qi¹, Shutong Yu², Zhengkun Dong³, Jiang Liu⁴, Juan Deng⁴, Guojian Mei⁴, Chuou Yin⁴, Qiao Li⁴, Tian Li⁵, Shi Wang⁶, Yibao Zhang⁷

Affiliations

¹ Department of Engineering Physics, Tsinghua University, Haidian District, Beijing, P. R. China, Beijing, Beijing, 100084, CHINA.
² Peking University Health Science Center Institute of Medical Technology, Haidian District, Beijing, 100084, P. R. China, Beijing, 100142, CHINA.
³ Institute of Medical Technology, Peking University Health Science Center, 38 Xueyuan Rd , Haidian District,Beijing,China, Beijing, 100191, CHINA.
⁴ Deyang People's Hospital, Taishan North Road, Deyang City, Deyang, Sichuan, 618000, CHINA.
⁵ Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon，Hong Kong, Kowloon, Hong Kong SAR, 999077, HONG KONG.
⁶ Department of Engineering Physics, Tsinghua University, Haidian District, Beijing, 100084, P. R. China, Beijing, Beijing, 100084, CHINA.
⁷ Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing Cancer Hospital & Institute, Beijing, China, 38 Xueyuan Rd , Haidian District,Beijing,China, Beijing, 100142, CHINA.

PMID: 39378911
DOI: 10.1088/1361-6560/ad84b1

Abstract

Megavoltage cone-beam CT (MV-CBCT) is advantageous in metal artifact reduction during Image-Guided Radiotherapy (IGRT), although it is limited by poor soft tissue contrast. This study proposed and evaluated a novel hybrid modality dual-energy (DE) imaging method combining the complementary advantages of kV-CT and MV-CBCT.Approach: The kV-CT and MV-CBCT images were acquired on a planning CT scanner and a Halcyon linear accelerator respectively. After rigid registration, images of basis materials were generated using the iterative decomposition method in the volumetric images. The decomposition accuracy was quantitatively evaluated on a Gammex 1472 phantom. The performance of contrast enhancement and metal artifact reduction in virtual monochromatic images were evaluated on both phantom and patient studies.Main results: Using the proposed method, the mean percentage errors for RED and SPR were 0.90% and 0.81%, outperforming the clinical single-energy mapping method with mean errors of 1.28% and 1.07%, respectively. The contrasts of soft-tissue insets were enhanced by a factor of 2~3 at 40 keV compared to kV-CT. The standard deviation in the metal artifact area was reduced by ~67%, from 42 HU (kV-CT) to 14 HU (150 keV monochromatic). The head and neck patient test showed that the percent error of soft-tissue RED in the metal artifact area was reduced from 18.1% (HU-RED conversion) to less than 1.0% (the proposed method), which was equivalent to the maximum dosimetric difference of 28.7% based on the patient-specific plan.Significance: Without hardware modification or extra imaging dose, the proposed hybrid modality method enabled kV-MV DE imaging, providing improved accuracy of quantitative analysis, soft-tissue contrast and metal artifact suppression for more accurate IGRT.&#xD.

Keywords: Dual-energy imaging; IGRT; MV-CBCT; Material decomposition; Metal artifacts.