Role of Daily Plan Adaptation in MR-Guided Stereotactic Ablative Radiation Therapy for Adrenal Metastases

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Abstract

AbstractPurpose

To study inter-fractional organ changes during MR-guided stereotactic ablative radiotherapy (SABR) for adrenal metastases and to evaluate the dosimetric advantages of online plan adaptation.

Methods and Materials

Seventeen patients underwent a total of 84 fractions of video-assisted, respiration-gated MR-guided adaptive radiotherapy to deliver either 50 Gy (5 fractions), 60 Gy (8 fractions) or 24 Gy (3 fractions). An MR scan was repeated prior to each fraction, followed by rigid co-registration to the GTV on the pre-treatment MR scan. Contour deformation, PTV (GTV+3mm) expansion and online plan re-optimization were then performed. Re-optimized plans were compared to baseline treatment plans recalculated on the anatomy-of-the-day (‘predicted plans').

Inter-fractional changes in OARs were quantified according to OAR volume changes within a 3 cm distance from PTV surface, centre of mass (COM) displacements and the Dice Similarity Coefficient (DSC). Plan quality evaluation was based on target coverage (GTV and PTV), and also high dose sparing of all OARs (V36Gy, V33Gy and V25Gy).

Results

Substantial COM displacements were observed for stomach, bowel and duodenum of 17, 27 and 36 mm, respectively. Maximum volume changes for the stomach, bowel and duodenum within 3 cm of PTV were 23.8, 20.5 and 20.9 cc, respectively. DSC values for OARs ranged from 0.0 to 0.9 for all fractions.

Baseline plans recalculated on anatomy-of-the-day revealed underdosage of target volumes, and variable OAR sparing, leading to a failure to meet institutional constraints in a third of fractions. Online re-optimization improved target coverage in 63% of fractions, and reduced the number of fractions not meeting the V95% objective for GTV and PTV. Re-optimized plans exhibited significantly better sparing of OAR.

Conclusions

Significant inter-fractional changes in OARs positions were observed despite breath-hold SABR delivery under MR-guidance. Online re-optimization of treatment plans led to significant improvements in target coverage and OAR sparing.

Original languageEnglish
Pages (from-to)426-433
Number of pages8
JournalInternational journal of radiation oncology, biology, physics
Volume102
Issue number2
DOIs
Publication statusPublished - 1 Oct 2018

Cite this

@article{3e34f1b4cc2c444e82af17681f9091d4,
title = "Role of Daily Plan Adaptation in MR-Guided Stereotactic Ablative Radiation Therapy for Adrenal Metastases",
abstract = "AbstractPurposeTo study inter-fractional organ changes during MR-guided stereotactic ablative radiotherapy (SABR) for adrenal metastases and to evaluate the dosimetric advantages of online plan adaptation.Methods and MaterialsSeventeen patients underwent a total of 84 fractions of video-assisted, respiration-gated MR-guided adaptive radiotherapy to deliver either 50 Gy (5 fractions), 60 Gy (8 fractions) or 24 Gy (3 fractions). An MR scan was repeated prior to each fraction, followed by rigid co-registration to the GTV on the pre-treatment MR scan. Contour deformation, PTV (GTV+3mm) expansion and online plan re-optimization were then performed. Re-optimized plans were compared to baseline treatment plans recalculated on the anatomy-of-the-day (‘predicted plans').Inter-fractional changes in OARs were quantified according to OAR volume changes within a 3 cm distance from PTV surface, centre of mass (COM) displacements and the Dice Similarity Coefficient (DSC). Plan quality evaluation was based on target coverage (GTV and PTV), and also high dose sparing of all OARs (V36Gy, V33Gy and V25Gy).ResultsSubstantial COM displacements were observed for stomach, bowel and duodenum of 17, 27 and 36 mm, respectively. Maximum volume changes for the stomach, bowel and duodenum within 3 cm of PTV were 23.8, 20.5 and 20.9 cc, respectively. DSC values for OARs ranged from 0.0 to 0.9 for all fractions.Baseline plans recalculated on anatomy-of-the-day revealed underdosage of target volumes, and variable OAR sparing, leading to a failure to meet institutional constraints in a third of fractions. Online re-optimization improved target coverage in 63{\%} of fractions, and reduced the number of fractions not meeting the V95{\%} objective for GTV and PTV. Re-optimized plans exhibited significantly better sparing of OAR.ConclusionsSignificant inter-fractional changes in OARs positions were observed despite breath-hold SABR delivery under MR-guidance. Online re-optimization of treatment plans led to significant improvements in target coverage and OAR sparing.",
author = "M.A. Palacios and O. Bohoudi and A.M.E. Bruynzeel and {van S{\"o}rnsen-de Koste}, J.R. and P. Cobussen and B.J. Slotman and F.J. Lagerwaard and S. Senan",
year = "2018",
month = "10",
day = "1",
doi = "10.1016/j.ijrobp.2018.06.002",
language = "English",
volume = "102",
pages = "426--433",
journal = "International Journal of Radiation Oncology Biology Physics",
issn = "0360-3016",
publisher = "Elsevier Inc.",
number = "2",

}

TY - JOUR

T1 - Role of Daily Plan Adaptation in MR-Guided Stereotactic Ablative Radiation Therapy for Adrenal Metastases

AU - Palacios, M.A.

AU - Bohoudi, O.

AU - Bruynzeel, A.M.E.

AU - van Sörnsen-de Koste, J.R.

AU - Cobussen, P.

AU - Slotman, B.J.

AU - Lagerwaard, F.J.

AU - Senan, S.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - AbstractPurposeTo study inter-fractional organ changes during MR-guided stereotactic ablative radiotherapy (SABR) for adrenal metastases and to evaluate the dosimetric advantages of online plan adaptation.Methods and MaterialsSeventeen patients underwent a total of 84 fractions of video-assisted, respiration-gated MR-guided adaptive radiotherapy to deliver either 50 Gy (5 fractions), 60 Gy (8 fractions) or 24 Gy (3 fractions). An MR scan was repeated prior to each fraction, followed by rigid co-registration to the GTV on the pre-treatment MR scan. Contour deformation, PTV (GTV+3mm) expansion and online plan re-optimization were then performed. Re-optimized plans were compared to baseline treatment plans recalculated on the anatomy-of-the-day (‘predicted plans').Inter-fractional changes in OARs were quantified according to OAR volume changes within a 3 cm distance from PTV surface, centre of mass (COM) displacements and the Dice Similarity Coefficient (DSC). Plan quality evaluation was based on target coverage (GTV and PTV), and also high dose sparing of all OARs (V36Gy, V33Gy and V25Gy).ResultsSubstantial COM displacements were observed for stomach, bowel and duodenum of 17, 27 and 36 mm, respectively. Maximum volume changes for the stomach, bowel and duodenum within 3 cm of PTV were 23.8, 20.5 and 20.9 cc, respectively. DSC values for OARs ranged from 0.0 to 0.9 for all fractions.Baseline plans recalculated on anatomy-of-the-day revealed underdosage of target volumes, and variable OAR sparing, leading to a failure to meet institutional constraints in a third of fractions. Online re-optimization improved target coverage in 63% of fractions, and reduced the number of fractions not meeting the V95% objective for GTV and PTV. Re-optimized plans exhibited significantly better sparing of OAR.ConclusionsSignificant inter-fractional changes in OARs positions were observed despite breath-hold SABR delivery under MR-guidance. Online re-optimization of treatment plans led to significant improvements in target coverage and OAR sparing.

AB - AbstractPurposeTo study inter-fractional organ changes during MR-guided stereotactic ablative radiotherapy (SABR) for adrenal metastases and to evaluate the dosimetric advantages of online plan adaptation.Methods and MaterialsSeventeen patients underwent a total of 84 fractions of video-assisted, respiration-gated MR-guided adaptive radiotherapy to deliver either 50 Gy (5 fractions), 60 Gy (8 fractions) or 24 Gy (3 fractions). An MR scan was repeated prior to each fraction, followed by rigid co-registration to the GTV on the pre-treatment MR scan. Contour deformation, PTV (GTV+3mm) expansion and online plan re-optimization were then performed. Re-optimized plans were compared to baseline treatment plans recalculated on the anatomy-of-the-day (‘predicted plans').Inter-fractional changes in OARs were quantified according to OAR volume changes within a 3 cm distance from PTV surface, centre of mass (COM) displacements and the Dice Similarity Coefficient (DSC). Plan quality evaluation was based on target coverage (GTV and PTV), and also high dose sparing of all OARs (V36Gy, V33Gy and V25Gy).ResultsSubstantial COM displacements were observed for stomach, bowel and duodenum of 17, 27 and 36 mm, respectively. Maximum volume changes for the stomach, bowel and duodenum within 3 cm of PTV were 23.8, 20.5 and 20.9 cc, respectively. DSC values for OARs ranged from 0.0 to 0.9 for all fractions.Baseline plans recalculated on anatomy-of-the-day revealed underdosage of target volumes, and variable OAR sparing, leading to a failure to meet institutional constraints in a third of fractions. Online re-optimization improved target coverage in 63% of fractions, and reduced the number of fractions not meeting the V95% objective for GTV and PTV. Re-optimized plans exhibited significantly better sparing of OAR.ConclusionsSignificant inter-fractional changes in OARs positions were observed despite breath-hold SABR delivery under MR-guidance. Online re-optimization of treatment plans led to significant improvements in target coverage and OAR sparing.

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U2 - 10.1016/j.ijrobp.2018.06.002

DO - 10.1016/j.ijrobp.2018.06.002

M3 - Article

VL - 102

SP - 426

EP - 433

JO - International Journal of Radiation Oncology Biology Physics

JF - International Journal of Radiation Oncology Biology Physics

SN - 0360-3016

IS - 2

ER -