Anatomical robust optimization to account for nasal cavity filling variation during intensity-modulated proton therapy: a comparison with conventional and adaptive planning strategies

被引：45

作者：

van de Water, Steven ^{[1
]}

Albertini, Francesca ^{[2
]}

Weber, Damien C. ^{[2
,3
]}

Heijmen, Ben J. M. ^{[1
]}

Hoogeman, Mischa S. ^{[1
]}

Lomax, Antony J. ^{[2
]}

机构：

[1] Erasmus MC, Dept Radiat Oncol, Canc Inst, Groene Hilledijk 301, NL-3075 EA Rotterdam, Netherlands

[2] Paul Scherrer Inst, Ctr Proton Therapy, CH-5232 Villigen, Switzerland

[3] Univ Hosp Bern, Dept Radiat Oncol, Bern, Switzerland

来源：

PHYSICS IN MEDICINE AND BIOLOGY | 2018年 / 63卷 / 02期

关键词：

proton therapy; IMPT; robust optimization; adaptive radiotherapy; plan adaptation; nasal cavity filling; sinonasal tumors; OROPHARYNGEAL CANCER-PATIENTS; LONG-TERM OUTCOMES; TREATMENT UNCERTAINTIES; MOTION MANAGEMENT; PARANASAL SINUS; BEAM ANGLE; RADIOTHERAPY; IMRT; SENSITIVITY; MODEL;

D O I：

10.1088/1361-6560/aa9c1c

中图分类号：

R318 [生物医学工程];

学科分类号：

0831 ;

摘要：

The aim of this study is to develop an anatomical robust optimization method for intensity-modulated proton therapy (IMPT) that accounts for interfraction variations in nasal cavity filling, and to compare it with conventional single-field uniform dose (SFUD) optimization and online plan adaptation. We included CT data of five patients with tumors in the sinonasal region. Using the planning CT, we generated for each patient 25 'synthetic' CTs with varying nasal cavity filling. The robust optimization method available in our treatment planning system 'Erasmus-iCycle' was extended to also account for anatomical uncertainties by including (synthetic) CTs with varying patient anatomy as error scenarios in the inverse optimization. For each patient, we generated treatment plans using anatomical robust optimization and, for benchmarking, using SFUD optimization and online plan adaptation. Clinical target volume (CTV) and organ-at-risk (OAR) doses were assessed by recalculating the treatment plans on the synthetic CTs, evaluating dose distributions individually and accumulated over an entire fractionated 50 Gy(RBE) treatment, assuming each synthetic CT to correspond to a 2 Gy(RBE) fraction. Treatment plans were also evaluated using actual repeat CTs. Anatomical robust optimization resulted in adequate CTV doses (V-95% >= 98% and V-107% <= 2%) if at least three synthetic CTs were included in addition to the planning CT. These CTV requirements were also fulfilled for online plan adaptation, but not for the SFUD approach, even when applying a margin of 5 mm. Compared with anatomical robust optimization, OAR dose parameters for the accumulated dose distributions were on average 5.9 Gy(RBE) (20%) higher when using SFUD optimization and on average 3.6 Gy(RBE) (18%) lower for online plan adaptation. In conclusion, anatomical robust optimization effectively accounted for changes in nasal cavity filling during IMPT, providing substantially improved CTV and OAR doses compared with conventional SFUD optimization. OAR doses can be further reduced by using online plan adaptation.

引用

页数：11