Evidence map›Paper›PMID 41845446›Full record

ArticleRadiation oncology (London, England)2026

Dose calculation accuracy with extended CT scales near metal: phantom-patient evaluation using a beam-metal overlap metric.

Minsoo Chun, Hosik Kim, Jaewon Hong, Jin Hwa Choi, Seungwan Lee, Inbum Lee, Jung-In Kim, Seonghee Kang

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Article in Radiation oncology (London, England), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

8 authors.

Minsoo ChunDepartment of Radiation Oncology, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Gyeonggi-do, 14353, Republic of Korea.
Hosik KimDepartment of Radiation Oncology, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Gyeonggi-do, 14353, Republic of Korea.
Jaewon HongDepartment of Radiation Oncology, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Gyeonggi-do, 14353, Republic of Korea.
Jin Hwa ChoiDepartment of Radiation Oncology, Chung-Ang University College of Medicine, Seoul, 06974, Republic of Korea.
Seungwan LeeDepartment of Radiological Science, Konyang University, Daejeon, 35365, Republic of Korea.
Inbum LeeInstitute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.
Jung-In KimInstitute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.
Seonghee KangInstitute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea. kangsh012@gmail.com.

Funding

National Research Foundation of Korea RS-2023-00211810Seoul National University Hospital, South Korea 0420250540
6 · The paper itself

Abstract

backgroundWe evaluated whether 16-bit CT reconstruction with explicit CT-to-electron-density (CT-to-ED) calibration improves dose-calculation accuracy versus conventional 12-bit reconstruction in the presence of metallic implants, and whether geometric metrics can identify cases that benefit most.

methodsCT-to-ED tables were built for both bit depths. In Solid Water, dose profiles and absolute dose were compared against EBT4 film and TG-51 ion-chamber measurements. Eight clinical IMRT plans were optimized and cross-recalculated between bit-depth domains with segments and monitor units fixed. A beam–metal interaction metric, ηmetal (monitor-unit–weighted beam’s-eye-view overlap), and the volumetric overlap ratio (VOR) between metal and PTV were computed. Gamma passing rate (GPR, 3 mm/3%), mean gamma, profile error, and absolute-dose deviation were evaluated.

resultsIn the phantom, 16-bit improved agreement over 12-bit, yielding higher GPR, profile differences ≤ 2%, and absolute-dose errors ≤ 1.0%; 12-bit showed profile errors up to 5.4% (stainless steel) and 3.0% (titanium) and absolute-dose errors of 2.3% and 1.7%. In patients, ηmetal > 35% was associated with GPR < 90% when 12-bit plans were recalculated on 16-bit, whereas low ηmetal maintained ≥ 90%. ηmetal correlated positively with VOR and negatively with GPR, supporting pre-treatment triage via VOR.

conclusionsExtended-bit reconstruction mitigates HU saturation, improves RED assignment, and yields better agreement with measurements and calculation. These findings support adopting 16-bit CT with CT-to-ED calibration as the default for planning and verification in patients with metallic implants, with VOR or ηmetal flagging cases where benefit is greatest.

Indexed as

Image Processing, Computer-AssistedMetalsPhantoms, ImagingProstheses and ImplantsRadiotherapy Planning, Computer-AssistedTomography, X-Ray ComputedCalibrationHumansRadiotherapy DosageRadiotherapy, Intensity-ModulatedMetals16-bit reconstructionDose calculation accuracyExtended CT scaleHounsfield Unit saturationRadiotherapy for metal implants

Identifiers

PMID41845446
PMCPMC13107909

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.