Optimizing patient positioning for intensity modulated radiation therapy in hippocampal-sparing whole brain radiation therapy

Siglin, Joshua; Champ, Colin E.; Vakhnenko, Yelena; Witek, Matthew E.; Peng, Cheng; Zaorsky, Nicholas G.; Harrison, A; Shi, Wenyin

doi:10.1016/j.prro.2013.11.008

Cited by 18 publications

(6 citation statements)

References 13 publications

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“…Additionally, our future work will include investigation of other techniques such as head tilting for HA-WBRT setup. Other reports in the literature show the tilted head geometry may reduce treatment time for the static-field IMRT modality [ 32 ], though it is unknown if it would also improve the dosimetry compared to the current data.…”

Section: Discussionmentioning

confidence: 79%

Dosimetric Evaluation of Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Helical Tomotherapy for Hippocampal-Avoidance Whole Brain Radiotherapy

et al. 2015

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BackgroundWhole brain radiotherapy (WBRT) is a vital tool in radiation oncology and beyond, but it can result in adverse health effects such as neurocognitive decline. Hippocampal Avoidance WBRT (HA-WBRT) is a strategy that aims to mitigate the neuro-cognitive side effects of whole brain radiotherapy treatment by sparing the hippocampi while delivering the prescribed dose to the rest of the brain. Several competing modalities capable of delivering HA-WBRT, include: Philips Pinnacle step-and-shoot intensity modulated radiotherapy (IMRT), Varian RapidArc volumetric modulated arc therapy (RapidArc), and helical TomoTherapy (TomoTherapy).MethodsIn this study we compared these methods using 10 patient datasets. Anonymized planning CT (computerized tomography) scans and contour data based on fused MRI images were collected. Three independent planners generated treatment plans for the patients using three modalities, respectively. All treatment plans met the RTOG 0933 criteria for HA-WBRT treatment.ResultsIn dosimetric comparisons between the three modalities, TomoTherapy has a significantly superior homogeneity index of 0.15 ± 0.03 compared to the other two modalities (0.28 ± .04, p < .005 for IMRT and 0.22 ± 0.03, p < .005 for RapidArc). RapidArc has the fastest average delivery time of 2.5 min compared to the other modalities (15 min for IMRT and 18 min for TomoTherapy).ConclusionTomoTherapy is considered to be the preferred modality for HA-WBRT due to its superior dose distribution. When TomoTherapy is not available or treatment time is a concern, RapidArc can provide sufficient dose distribution meeting RTOG criteria and efficient treatment delivery.

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Section: Discussionmentioning

confidence: 79%

Dosimetric Evaluation of Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Helical Tomotherapy for Hippocampal-Avoidance Whole Brain Radiotherapy

et al. 2015

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“…Clinical data suggests that the approach is safe and favourable in terms of neurological outcome [ 25 – 27 ]. For hippocampal sparing WBRT, also the influence of patient positioning on the hippocampal dose exposure has been investigated, and there is data suggesting that an inclined head angle might be beneficial [ 28 ]. In our study, it was not investigated whether an inclined head angle is able to further improve hippocampal dose in radiotherapy for glioblastoma, as all patients were positioned in the standard way.…”

Section: Discussionmentioning

confidence: 99%

Hippocampal sparing radiotherapy for glioblastoma patients: a planning study using volumetric modulated arc therapy

et al. 2016

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BackgroundThe purpose of this study is to investigate the potential to reduce exposure of the contralateral hippocampus in radiotherapy for glioblastoma using volumetric modulated arc therapy (VMAT).MethodsDatasets of 27 patients who had received 3D conformal radiotherapy (3D-CRT) for glioblastoma with a prescribed dose of 60Gy in fractions of 2Gy were included in this planning study. VMAT plans were optimized with the aim to reduce the dose to the contralateral hippocampus as much as possible without compromising other parameters. Hippocampal dose and treatment parameters were compared to the 3D-CRT plans using the Wilcoxon signed-rank test. The influence of tumour location and PTV size on the hippocampal dose was investigated with the Mann–Whitney-U-test and Spearman’s rank correlation coefficient.ResultsThe median reduction of the contralateral hippocampus generalized equivalent uniform dose (gEUD) with VMAT was 36 % compared to the original 3D-CRT plans (p < 0.05). Other dose parameters were maintained or improved. The median V30Gy brain could be reduced by 17.9 % (p < 0.05). For VMAT, a parietal and a non-temporal tumour localisation as well as a larger PTV size were predictors for a higher hippocampal dose (p < 0.05).ConclusionsUsing VMAT, a substantial reduction of the radiotherapy dose to the contralateral hippocampus for patients with glioblastoma is feasible without compromising other treatment parameters. For larger PTV sizes, less sparing can be achieved. Whether this approach is able to preserve the neurocognitive status without compromising the oncological outcome needs to be investigated in the setting of prospective clinical trials.

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“…In a study by Abayomi [8], the hippocampus and surrounding medial temporal lobe cortex were identi ed as the critical area where radiation generates neurocognitive decline. It is possible that the high radiation sensitivity of the progenitor neural cells located in the dentate gyrus of the hippocampus is the reason for the previously described affections [9,10]. Therefore, it is suggested that WBRT with sparing of hippocampi (WBRT-HS) may be an effective treatment option for most patients with brain metastases, in order to minimize any possible cognitive decline.…”

Section: Introductionmentioning

confidence: 99%

“…Performing WBRT-HS requires complex treatment planning and the rst studies in this area were made using helical tomotherapy [12][13][14] or linear accelerators based techniques, such as intensity modulated radiotherapy (IMRT) [10,15] and volumetric modulated arc therapy (VMAT) [16,17]. There are even studies where the these techniques are compared simultaneously [18].…”

Section: Introductionmentioning

confidence: 99%

Dosimetric Evaluation of a Hybrid Treatment Planning for Whole-Brain Radiation with Hippocampal Sparing

Martín-Tovar

ALVARADO

POOT

et al. 2022

Preprint

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Purpose To investigate the effect of a Hybrid planning technique which results from combining intensity modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) for whole brain radiation therapy hippocampal-sparing (WBRT-HS). Methods Three types of plans were made for 15 patients, namely Hybrid, pure IMRT, and pure VMAT and retrospectively compared. All plans were made using the same contours based on the original computed tomography (CT) scans fused with magnetic resonance imaging (MRI). Plan quality was determined by calculating the conformity (CI) and homogeneity (HI) indices of planning target volumes (PTVs). The three types of plans were compared in terms of dose to organs at risk (OARs), number of monitor units (MUs), and treatment time. Results Hybrid plans showed improved homogeneity (p = 0.04) and conformity (p = 0.01) indices compared to IMRT and VMAT plans. In terms of hippocampus sparing, the Hybrid technique showed almost equal D100% and maximum dose (Dmax) values compared to the other techniques, but without statistical significance (p > 0.05); however, there was a significant difference for the left hippocampus, where the IMRT technique obtained the best result (p < 0.001). Regarding the dose delivered to the remaining OARs, MUs and treatment times, all values for the Hybrid plans were between those of IMRT and VMAT. Conclusion Compared to IMRT and VMAT plans, the Hybrid plan allowed a better conformity and homogeneity for the dose distribution in the PTV with intermediate dose values to the OARs.

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Optimizing patient positioning for intensity modulated radiation therapy in hippocampal-sparing whole brain radiation therapy

Cited by 18 publications

References 13 publications

Dosimetric Evaluation of Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Helical Tomotherapy for Hippocampal-Avoidance Whole Brain Radiotherapy

Dosimetric Evaluation of Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, and Helical Tomotherapy for Hippocampal-Avoidance Whole Brain Radiotherapy

Hippocampal sparing radiotherapy for glioblastoma patients: a planning study using volumetric modulated arc therapy

Dosimetric Evaluation of a Hybrid Treatment Planning for Whole-Brain Radiation with Hippocampal Sparing

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