Uniform versus non-uniform dose prescription for proton stereotactic body radiotherapy of liver tumors investigated by extensive motion-including treatment simulations

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Uniform versus non-uniform dose prescription for proton stereotactic body radiotherapy of liver tumors investigated by extensive motion-including treatment simulations. / Worm, Esben Schjodt; Hansen, Rune; Hoyer, Morten; Weber, Britta; Mortensen, Hanna; Poulsen, Per Rugaard.

I: Physics in Medicine and Biology, Bind 66, Nr. 20, 205009, 10.2021.

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

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@article{1ffd3d361b364881846a05b7b9b58b60,
title = "Uniform versus non-uniform dose prescription for proton stereotactic body radiotherapy of liver tumors investigated by extensive motion-including treatment simulations",
abstract = "Compared to x-ray-based stereotactic body radiotherapy (SBRT) of liver cancer, proton SBRT may reduce the normal liver tissue dose. For an optimal trade-off between target and liver dose, a non-uniform dose prescription is often applied in x-ray SBRT, but lacks investigation for proton SBRT. Also, proton SBRT is prone to breathing-induced motion-uncertainties causing target mishit or dose alterations by interplay with the proton delivery. This study investigated non-uniform and uniform dose prescription in proton-based liver SBRT, including effects of rigid target motion observed during planning-4DCT and treatment. The study was based on 42 x-ray SBRT fractions delivered to 14 patients under electromagnetic motion-monitoring. For each patient, a non-uniform and uniform proton plan were made. The uniform plan was renormalized to be iso-toxic with the non-uniform plan using a NTCP model for radiation-induced liver disease. The motion data were used in treatment simulations to estimate the delivered target dose with rigid motion. Treatment simulations were performed with and without a repainting scheme designed to mitigate interplay effects. Including rigid motion, the achieved CTV mean dose after three fractions delivered without repainting was on average (SD) 24.8 8.4% higher and the D98% was 16.2 11.3% higher for non-uniform plans than for uniform plans. The interplay-induced increase in D2% relative to the static plans was reduced from 3.2 4.1% without repainting to -0.5 1.7% with repainting for non-uniform plans and from 1.5 2.0% to 0.1 1.3% for uniform plans. Considerable differences were observed between estimated CTV doses based on 4DCT motion and intra-treatment motion. In conclusion, non-uniform dose prescription in proton SBRT may provide considerably higher tumor doses than uniform prescription for the same complication risk. Due to motion variability, target doses estimated from 4DCT motion may not accurately reflect the delivered dose. Future studies including modelling of deformations and associated range uncertainties are warranted to confirm the findings. ",
keywords = "intrafraction motion, liver SBRT, particle therapy, treatment planning",
author = "Worm, {Esben Schjodt} and Rune Hansen and Morten Hoyer and Britta Weber and Hanna Mortensen and Poulsen, {Per Rugaard}",
note = "Publisher Copyright: {\textcopyright} 2021 Institute of Physics and Engineering in Medicine.",
year = "2021",
month = oct,
doi = "10.1088/1361-6560/ac2880",
language = "English",
volume = "66",
journal = "Physics in Medicine and Biology",
issn = "0031-9155",
publisher = "Institute of Physics Publishing Ltd.",
number = "20",

}

RIS

TY - JOUR

T1 - Uniform versus non-uniform dose prescription for proton stereotactic body radiotherapy of liver tumors investigated by extensive motion-including treatment simulations

AU - Worm, Esben Schjodt

AU - Hansen, Rune

AU - Hoyer, Morten

AU - Weber, Britta

AU - Mortensen, Hanna

AU - Poulsen, Per Rugaard

N1 - Publisher Copyright: © 2021 Institute of Physics and Engineering in Medicine.

PY - 2021/10

Y1 - 2021/10

N2 - Compared to x-ray-based stereotactic body radiotherapy (SBRT) of liver cancer, proton SBRT may reduce the normal liver tissue dose. For an optimal trade-off between target and liver dose, a non-uniform dose prescription is often applied in x-ray SBRT, but lacks investigation for proton SBRT. Also, proton SBRT is prone to breathing-induced motion-uncertainties causing target mishit or dose alterations by interplay with the proton delivery. This study investigated non-uniform and uniform dose prescription in proton-based liver SBRT, including effects of rigid target motion observed during planning-4DCT and treatment. The study was based on 42 x-ray SBRT fractions delivered to 14 patients under electromagnetic motion-monitoring. For each patient, a non-uniform and uniform proton plan were made. The uniform plan was renormalized to be iso-toxic with the non-uniform plan using a NTCP model for radiation-induced liver disease. The motion data were used in treatment simulations to estimate the delivered target dose with rigid motion. Treatment simulations were performed with and without a repainting scheme designed to mitigate interplay effects. Including rigid motion, the achieved CTV mean dose after three fractions delivered without repainting was on average (SD) 24.8 8.4% higher and the D98% was 16.2 11.3% higher for non-uniform plans than for uniform plans. The interplay-induced increase in D2% relative to the static plans was reduced from 3.2 4.1% without repainting to -0.5 1.7% with repainting for non-uniform plans and from 1.5 2.0% to 0.1 1.3% for uniform plans. Considerable differences were observed between estimated CTV doses based on 4DCT motion and intra-treatment motion. In conclusion, non-uniform dose prescription in proton SBRT may provide considerably higher tumor doses than uniform prescription for the same complication risk. Due to motion variability, target doses estimated from 4DCT motion may not accurately reflect the delivered dose. Future studies including modelling of deformations and associated range uncertainties are warranted to confirm the findings.

AB - Compared to x-ray-based stereotactic body radiotherapy (SBRT) of liver cancer, proton SBRT may reduce the normal liver tissue dose. For an optimal trade-off between target and liver dose, a non-uniform dose prescription is often applied in x-ray SBRT, but lacks investigation for proton SBRT. Also, proton SBRT is prone to breathing-induced motion-uncertainties causing target mishit or dose alterations by interplay with the proton delivery. This study investigated non-uniform and uniform dose prescription in proton-based liver SBRT, including effects of rigid target motion observed during planning-4DCT and treatment. The study was based on 42 x-ray SBRT fractions delivered to 14 patients under electromagnetic motion-monitoring. For each patient, a non-uniform and uniform proton plan were made. The uniform plan was renormalized to be iso-toxic with the non-uniform plan using a NTCP model for radiation-induced liver disease. The motion data were used in treatment simulations to estimate the delivered target dose with rigid motion. Treatment simulations were performed with and without a repainting scheme designed to mitigate interplay effects. Including rigid motion, the achieved CTV mean dose after three fractions delivered without repainting was on average (SD) 24.8 8.4% higher and the D98% was 16.2 11.3% higher for non-uniform plans than for uniform plans. The interplay-induced increase in D2% relative to the static plans was reduced from 3.2 4.1% without repainting to -0.5 1.7% with repainting for non-uniform plans and from 1.5 2.0% to 0.1 1.3% for uniform plans. Considerable differences were observed between estimated CTV doses based on 4DCT motion and intra-treatment motion. In conclusion, non-uniform dose prescription in proton SBRT may provide considerably higher tumor doses than uniform prescription for the same complication risk. Due to motion variability, target doses estimated from 4DCT motion may not accurately reflect the delivered dose. Future studies including modelling of deformations and associated range uncertainties are warranted to confirm the findings.

KW - intrafraction motion

KW - liver SBRT

KW - particle therapy

KW - treatment planning

UR - http://www.scopus.com/inward/record.url?scp=85117685230&partnerID=8YFLogxK

U2 - 10.1088/1361-6560/ac2880

DO - 10.1088/1361-6560/ac2880

M3 - Journal article

C2 - 34544071

AN - SCOPUS:85117685230

VL - 66

JO - Physics in Medicine and Biology

JF - Physics in Medicine and Biology

SN - 0031-9155

IS - 20

M1 - 205009

ER -