Quantitative assessment of deformable image registration accuracy for cumulative dose estimation in multi-site stereotactic re-irradiation
5 affiliations
- 1Department of Oncology, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
- 2Clinical Research, King Abdullah International Medical Research Center (KAIMRC), Riyadh, Kingdom of Saudi Arabia
- 3Advanced Management of Liver Malignancies Program, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
- 4Radiotherapy Unit, Pusat Perubatan Universiti Sains Malaysia, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
- 5Radiological Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
Abstract
Background: Re-irradiation of previously treated anatomical sites requires precise cumulative dose estimation to balance tumor control with organ-at-risk (OAR) tolerance. Conventional physical dose summation fails to account for inter-treatment anatomical deformations, potentially leading to systematic over- or underestimation of OAR doses. This study evaluates intensity-based deformable image registration (DIR) for improving dose accumulation accuracy in multiple stereotactic ablative radiotherapy (SABR) re-irradiation across different anatomical sites.
Methods: Sixty patients (226 lesions) who underwent robotic CyberKnife-based SABR re-irradiation (2–5 courses) to liver (36.7%), brain (36.7%), lung (10%), and spine (16.7%) metastases between 2016 and 2025 were analyzed. Cumulative OAR doses were calculated using both DIR-based approach and traditional physical summation. DIR registration accuracy was quantified using dice similarity coefficient (DSC), jaccard index (JI). Biologically effective dose (BED) and equivalent dose in 2 Gy fractions (EQD2) conversions were evaluated for dose assessments across heterogeneous fractionation schedules.
Results: DIR-based dose accumulation demonstrated significantly lower maximum doses compared with physical summation: liver maximum dose decreased from 123.8 ± 55.6 Gy to 83.2 ± 28.0 Gy (p < 0.001) and chest wall maximum dose reduced from 82.9 ± 22.4 Gy to 66.9 ± 18.6 Gy (p = 0.05). DIR yielded excellent spatial agreement for relatively rigid structures, including the heart, liver, kidneys, and brainstem (DSC > 0.90; JI > 0.84), whereas highly deformable organs such as the bowel and stomach demonstrated markedly inferior agreement (DSC < 0.50; JI < 0.35). Biological dose assessment revealed that DIR-guided workflow more accurately reflected cumulative dose patterns.
Conclusion: Deformable registration improves cumulative dose estimation accuracy for multiple SABR re-irradiation. Integration of validated DIR with quantitative quality assurance and biological dose modeling provides a robust framework for multiple re-irradiation workflows. Future prospective studies correlating DIR-derived doses with clinical toxicity are warranted to validate the clinical impact of improved dosimetric accuracy.
Related
- FlexiMIND: Combined Pretrained Vision Features and Local Structure for Training-Free Deformable Medical Image Registration
- Impact of segmented deformable mirrors on high-contrast testbeds for exoplanet imaging with future large space telescopes: contrast stability assessment on the HiCAT bench
- Assessment of Calculation Grid Size Impact on Plan Quality and Gamma Evaluation Metrics in Intracranial Stereotactic Radiotherapy
- Quantitative assessment of the influence of tapered dies and compaction position on the propensity of lamination due to air entrapment during pharmaceutical compression
- Optimization of a deformable mirror using covariance matrix adaptation evolution strategy.
BibTeX
@article{yoosuf2026quantitative,
title = {{Quantitative assessment of deformable image registration accuracy for cumulative dose estimation in multi-site stereotactic re-irradiation}},
author = {Ahamed Badusha Mohamed Yoosuf and Mohd Zahri Abdul Aziz and Salem Alshehri and Mamdouh Alqathami},
journal = {Radiation Oncology (London, England)},
year = {2026},
month = jul,
doi = {10.1186/s13014-026-02897-8},
url = {https://doi.org/10.1186/s13014-026-02897-8},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Quantitative assessment of deformable image registration accuracy for cumulative dose estimation in multi-site stereotactic re-irradiation
AU - Ahamed Badusha Mohamed Yoosuf
AU - Mohd Zahri Abdul Aziz
AU - Salem Alshehri
AU - Mamdouh Alqathami
PY - 2026
DA - 2026/07/31
JO - Radiation Oncology (London, England)
DO - 10.1186/s13014-026-02897-8
UR - https://doi.org/10.1186/s13014-026-02897-8
AB - Background: Re-irradiation of previously treated anatomical sites requires precise cumulative dose estimation to balance tumor control with organ-at-risk (OAR) tolerance. Conventional physical dose summation fails to account for inter-treatment anatomical deformations, potentially leading to systematic over- or underestimation of OAR doses. This study evaluates intensity-based deformable image registration (DIR) for improving dose accumulation accuracy in multiple stereotactic ablative radiotherapy (SABR) re-irradiation across different anatomical sites. Methods: Sixty patients (226 lesions) who underwent robotic CyberKnife-based SABR re-irradiation (2–5 courses) to liver (36.7%), brain (36.7%), lung (10%), and spine (16.7%) metastases between 2016 and 2025 were analyzed. Cumulative OAR doses were calculated using both DIR-based approach and traditional physical summation. DIR registration accuracy was quantified using dice similarity coefficient (DSC), jaccard index (JI). Biologically effective dose (BED) and equivalent dose in 2 Gy fractions (EQD2) conversions were evaluated for dose assessments across heterogeneous fractionation schedules. Results: DIR-based dose accumulation demonstrated significantly lower maximum doses compared with physical summation: liver maximum dose decreased from 123.8 ± 55.6 Gy to 83.2 ± 28.0 Gy (p < 0.001) and chest wall maximum dose reduced from 82.9 ± 22.4 Gy to 66.9 ± 18.6 Gy (p = 0.05). DIR yielded excellent spatial agreement for relatively rigid structures, including the heart, liver, kidneys, and brainstem (DSC > 0.90; JI > 0.84), whereas highly deformable organs such as the bowel and stomach demonstrated markedly inferior agreement (DSC < 0.50; JI < 0.35). Biological dose assessment revealed that DIR-guided workflow more accurately reflected cumulative dose patterns. Conclusion: Deformable registration improves cumulative dose estimation accuracy for multiple SABR re-irradiation. Integration of validated DIR with quantitative quality assurance and biological dose modeling provides a robust framework for multiple re-irradiation workflows. Future prospective studies correlating DIR-derived doses with clinical toxicity are warranted to validate the clinical impact of improved dosimetric accuracy.
SN - 1748-717X
ER -