TY - JOUR
T1 - Clinical benefit of range uncertainty reduction in proton treatment planning based on dual-energy CT for neuro-oncological patients
AU - Taasti, Vicki Trier
AU - Decabooter, Esther
AU - Eekers, Daniëlle
AU - Compter, Inge
AU - Rinaldi, Ilaria
AU - Bogowicz, Marta
AU - van der Maas, Tim
AU - Kneepkens, Esther
AU - Schiffelers, Jacqueline
AU - Stultiens, Cissy
AU - Hendrix, Nicole
AU - Pijls, Mirthe
AU - Emmah, Rik
AU - Fonseca, Gabriel Paiva
AU - Unipan, Mirko
AU - van Elmpt, Wouter
PY - 2023/9
Y1 - 2023/9
N2 - OBJECTIVE: Several studies have shown that dual-energy CT (DECT) can lead to improved accuracy for proton range estimation. This study investigated the clinical benefit of reduced range uncertainty, enabled by DECT, in robust optimisation for neuro-oncological patients. METHODS: DECT scans for 27 neuro-oncological patients were included. Commercial software was applied to create stopping-power ratio (SPR) maps based on the DECT scan. Two plans were robustly optimised on the SPR map, keeping the beam and plan settings identical to the clinical plan. One plan was robustly optimised and evaluated with a range uncertainty of 3% (as used clinically; denoted 3%-plan); the second plan applied a range uncertainty of 2% (2%-plan). Both plans were clinical acceptable and optimal. The dose-volume histogram parameters were compared between the two plans. Two experienced neuro-radiation oncologists determined the relevant dose difference for each organ-at-risk (OAR). Moreover, the OAR toxicity levels were assessed. RESULTS: For 24 patients, a dose reduction >0.5/1?Gy (relevant dose difference depending on the OAR) was seen in one or more OARs for the 2%-plan; . for brainstem D in 10 patients, and hippocampus D in 6 patients. Furthermore, 12 patients had a reduction in toxicity level for one or two OARs, showing a clear benefit for the patient. CONCLUSION: Robust optimisation with reduced range uncertainty allows for reduction of OAR toxicity, providing a rationale for clinical implementation. Based on these results, we have clinically introduced DECT-based proton treatment planning for neuro-oncological patients, accompanied with a reduced range uncertainty of 2%. ADVANCES IN KNOWLEDGE: This study shows the clinical benefit of range uncertainty reduction from 3% to 2% in robustly optimised proton plans. A dose reduction to one or more OARs was seen for 89% of the patients, and 44% of the patients had an expected toxicity level decrease.
AB - OBJECTIVE: Several studies have shown that dual-energy CT (DECT) can lead to improved accuracy for proton range estimation. This study investigated the clinical benefit of reduced range uncertainty, enabled by DECT, in robust optimisation for neuro-oncological patients. METHODS: DECT scans for 27 neuro-oncological patients were included. Commercial software was applied to create stopping-power ratio (SPR) maps based on the DECT scan. Two plans were robustly optimised on the SPR map, keeping the beam and plan settings identical to the clinical plan. One plan was robustly optimised and evaluated with a range uncertainty of 3% (as used clinically; denoted 3%-plan); the second plan applied a range uncertainty of 2% (2%-plan). Both plans were clinical acceptable and optimal. The dose-volume histogram parameters were compared between the two plans. Two experienced neuro-radiation oncologists determined the relevant dose difference for each organ-at-risk (OAR). Moreover, the OAR toxicity levels were assessed. RESULTS: For 24 patients, a dose reduction >0.5/1?Gy (relevant dose difference depending on the OAR) was seen in one or more OARs for the 2%-plan; . for brainstem D in 10 patients, and hippocampus D in 6 patients. Furthermore, 12 patients had a reduction in toxicity level for one or two OARs, showing a clear benefit for the patient. CONCLUSION: Robust optimisation with reduced range uncertainty allows for reduction of OAR toxicity, providing a rationale for clinical implementation. Based on these results, we have clinically introduced DECT-based proton treatment planning for neuro-oncological patients, accompanied with a reduced range uncertainty of 2%. ADVANCES IN KNOWLEDGE: This study shows the clinical benefit of range uncertainty reduction from 3% to 2% in robustly optimised proton plans. A dose reduction to one or more OARs was seen for 89% of the patients, and 44% of the patients had an expected toxicity level decrease.
KW - Humans
KW - Protons
KW - Proton Therapy/methods
KW - Uncertainty
KW - Tomography, X-Ray Computed/methods
KW - Radiotherapy Planning, Computer-Assisted/methods
U2 - 10.1259/bjr.20230110
DO - 10.1259/bjr.20230110
M3 - Article
SN - 0007-1285
VL - 96
JO - British Journal of Radiology
JF - British Journal of Radiology
IS - 1149
M1 - 20230110
ER -