MRI-based inter- and intrafraction motion analysis of the pancreatic tail and spleen as preparation for adaptive MRI-guided radiotherapy in neuroblastoma

Radiation Oncology

Research

Enrica Seravalli¹  Petra S. Kroon¹  Fasco Van Ommen¹  Mirjam E. Willemsen-Bosman¹  Gaelle A.T. le Quellenec²  Max M. van Noesel³  Geert O. Janssens³  Marry M. van den Heuvel-Eibrink⁴ 

[1] Department of Radiation Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands;Department of Radiation Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands;Department of Radiation Oncology, Institut de Cancérologie de l’Ouest, Nantes, France;Department of Radiation Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands;Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands;Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands;

关键词: Neuroblastoma;    Pediatric radiotherapy;    Interfraction motion;    Intrafraction motion;    MRI-guided radiotherapy;   

DOI  :  10.1186/s13014-023-02347-9

 received in 2023-06-28, accepted in 2023-09-06,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundIn pediatric radiotherapy treatment planning of abdominal tumors, dose constraints to the pancreatic tail/spleen are applied to reduce late toxicity. In this study, an analysis of inter- and intrafraction motion of the pancreatic tail/spleen is performed to estimate the potential benefits of online MRI-guided radiotherapy (MRgRT).Materials and methodsTen randomly selected neuroblastoma patients (median age: 3.4 years), irradiated with intensity-modulated arc therapy at our department (prescription dose: 21.6/1.8 Gy), were retrospectively evaluated for inter- and intrafraction motion of the pancreatic tail/spleen. Three follow-up MRIs (T2- and T1-weighted ± gadolinium) were rigidly registered to a planning CT (pCT), on the vertebrae around the target volume. The pancreatic tail/spleen were delineated on all MRIs and pCT. Interfraction motion was defined as a center of gravity change between pCT and T2-weighted images in left-right (LR), anterior-posterior (AP) and cranial-caudal (CC) direction. For intrafraction motion analysis, organ position on T1-weighted ± gadolinium was compared to T2-weighted. The clinical radiation plan was used to estimate the dose received by the pancreatic tail/spleen for each position.ResultsThe median (IQR) interfraction motion was minimal in LR/AP, and largest in CC direction; pancreatic tail 2.5 mm (8.9), and spleen 0.9 mm (3.9). Intrafraction motion was smaller, but showed a similar motion pattern (pancreatic tail, CC: 0.4 mm (1.6); spleen, CC: 0.9 mm (2.8)). The differences of Dmean associated with inter- and intrafraction motions ranged from − 3.5 to 5.8 Gy for the pancreatic tail and − 1.2 to 3.0 Gy for the spleen. In 6 out of 10 patients, movements of the pancreatic tail and spleen were highlighted as potentially clinically significant because of ≥ 1 Gy dose constraint violation.ConclusionInter- and intrafraction organ motion results into unexpected constrain violations in 60% of a randomly selected neuroblastoma cohort, supporting further prospective exploration of MRgRT.

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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