Inclined head position improves dose distribution during hippocampal-sparing whole brain radiotherapy using VMAT

Kim, Kyung Soo; Seo, Suk Jin; Lee, Jaegi; Seok, Jin Yong; Hong, Jung Kyung; Chung, Jae Yoon; Kim, Eunji; Choi, Nam Kyong; Eom, Keun Yong; Kim, Jae Sung; Kim, In Ah

doi:10.1007/s00066-016-0973-0

Cited by 12 publications

(9 citation statements)

References 23 publications

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“…The method explored here managed to produce a steeper dose gradient in all patients, including those with metastases located in the vicinity of the hippocampi. In spite of the strong dose modulation, the TC, conformity and homogeneity indices for whole brain and metastases obtained in this trial were adequate and comparable with the results of previous studies [ 16 , 30 – 32 ].…”

Section: Discussionsupporting

confidence: 88%

Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost—tutorial and efficacy of complete directional hippocampal blocking

et al. 2022

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Purpose Hippocampus-avoidance whole brain radiotherapy with simultaneous integrated boost (HA-WBRT+SIB) is a complex treatment option for patients with multiple brain metastases, aiming to prevent neurocognitive decline and simultaneously increase tumor control. Achieving efficient hippocampal dose reduction in this context can be challenging. The aim of the current study is to present and analyze the efficacy of complete directional hippocampal blocking in reducing the hippocampal dose during HA-WBRT+SIB. Methods A total of 30 patients with multiple metastases having undergone HA-WBRT+SIB were identified. The prescribed dose was 30 Gy in 12 fractions to the whole brain, with 98% of the hippocampus receiving ≤ 9 Gy and 2% ≤ 17 Gy and with SIB to metastases/resection cavities of 36–51 Gy in 12 fractions. Alternative treatment plans were calculated using complete directional hippocampal blocking and compared to conventional plans regarding target coverage, homogeneity, conformity, dose to hippocampi and organs at risk. Results All alternative plans reached prescription doses. Hippocampal blocking enabled more successful sparing of the hippocampus, with a mean dose of 8.79 ± 0.99 Gy compared to 10.07 ± 0.96 Gy in 12 fractions with the conventional method (p < 0.0001). The mean dose to the whole brain (excluding metastases and hippocampal avoidance region) was 30.52 ± 0.80 Gy with conventional planning and 30.28 ± 0.11 Gy with hippocampal blocking (p = 0.11). Target coverage, conformity and homogeneity indices for whole brain and metastases, as well as doses to organs at risk were similar between planning methods (p > 0.003). Conclusion Complete directional hippocampal blocking is an efficient method for achieving improved hippocampal sparing during HA-WBRT+SIB.

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Section: Discussionsupporting

confidence: 88%

Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost—tutorial and efficacy of complete directional hippocampal blocking

et al. 2022

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“…However, the availability of tomotherapy is limited, and the treatment planning time is significantly longer. Another possibility to improve the quality of the treatment planning could be an inclined head position [33,34]. In a recently published study, Zheng et al showed feasibility using VMAT and tomotherapy for HT-P and hippocampal axis sparing for cranio-spinal irradiation.…”

Section: Discussionmentioning

confidence: 99%

Sparing the hippocampus and the hypothalamic- pituitary region during whole brain radiotherapy: a volumetric modulated arc therapy planning study

et al. 2020

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Background: Feasibility testing of a simultaneous sparing approach of hippocampus, hypothalamus and pituitary gland in patients undergoing whole-brain radiotherapy (WBRT) with and without a concomitant boost to metastatic sites. Introduction: Cognitive impairment and hormonal dysfunction are common side effects of cranial radiotherapy. A reduced dose application to the patho-physiologically involved functional brain areas, i.e. hippocampus, hypothalamus and pituitary gland, could reduce these common side effects. While hippocampal sparing is already a common practice to improve cognitive outcome, technical experience of additional combined sparing of the hypothalamus/pituitary gland (HT-P) is insufficient. Methods: Twenty patients were included in the planning study. In 11 patients, a total dose of 36 Gy of WBRT (2 Gy per fraction) plus a simultaneous integrated boost (SIB) of 9 Gy (0.5 Gy per fraction, total dose: 45 Gy) to the brain metastases was applied. In 9 patients, prophylactic cranial irradiation (PCI) was simulated with a total dose of 30 Gy (2 Gy per fraction). In both patient cohorts, a sparing approach of the hippocampus and the HT-P area was simulated during WBRT. For all treatment plans, volumetric modulated arc therapy (VMAT) was used. Quality assurance included assessment of homogeneity, conformality and target coverage. Results: The mean dose to the hippocampus and HT-P region was limited to less than 50% of the prescribed dose to the planning target volume (PTV) in all treatment plans. Dose homogeneity (HI) of the target volume was satisfying (median HI = 0.16 for WBRT+SIB and 0.1 for PCI) and target coverage (conformation number, CN) was not compromised (median CN = 0.82 for SIB and 0.86 for PCI).

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“…All patients were positioned using a Variable Axis Baseplate ™ (CIVCO Medical Instruments, Kalona, IA, USA). The head was inclined as previously described [ 18 ]. The computed tomography (CT) scans were acquired by using a Brilliance CT Big Bore™ CT simulator (Philips, Cleveland, OH, USA) with a slice thickness of 2 mm.…”

Section: Methodsmentioning

confidence: 99%

Hippocampus-sparing radiotherapy using volumetric modulated arc therapy (VMAT) to the primary brain tumor: the result of dosimetric study and neurocognitive function assessment

et al. 2018

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BackgroundWe hypothesized that hippocampal-sparing radiotherapy via volumetric modulated arc therapy (VMAT) could preserve the neurocognitive function (NCF) of patients with primary brain tumors treated with radiotherapy.MethodsWe reviewed data from patients with primary brain tumors who underwent hippocampal-sparing brain radiotherapy via VMAT between February 2014 and December 2015. The optimization criteria for the contralateral hippocampus was a maximum dose (Dmax) of less than 17 Gy. For NCF evaluations, the Seoul Verbal Learning Test for total recall, delayed recall, and recognition (SVLT-TR, DR, and Recognition) was performed at baseline and at seven months after radiotherapy.ResultsA total of 26 patients underwent NCF testing seven months after radiotherapy. Their median age was 49.5 years (range 26–77 years), and 14 (53.8%) had grade III/IV tumors. The median Dmax to the contralateral hippocampus was 16.4 Gy (range 3.5-63.4). The median mean dose to the contralateral hippocampus, expressed as equivalent to a 2-Gy dose (EQD2/2), was 7.4 Gy2 (0.7–13.1). The mean relative changes in SVLT-TR, SVLT-DR, and SVLT-Recognition at seven months compared to the baseline were − 7.7% (95% confidence interval [CI], − 19.6% to 4.2%), − 9.2% (95% CI, − 25.4% to 7.0%), and − 3.4% (− 12.7% to 5.8%), respectively. Two patients (7.7%) showed deteriorated NCF in the SVLT-TR and SVLT-DR, and three (11.5%) in the SVLT-Recognition. The mean dose of the left hippocampus and bilateral hippocampi were significantly higher in patients showing deterioration of the SVLT-TR and SVLT-Recognition than in those without deterioration.ConclusionsThe contralateral hippocampus could be effectively spared in patients with primary brain tumor via VMAT to preserve the verbal memory function. Further investigation is needed to identify those patients who will most benefit from hippocampal-sparing radiotherapy of the primary brain tumor.Electronic supplementary materialThe online version of this article (10.1186/s13014-018-0975-4) contains supplementary material, which is available to authorized users.

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Inclined head position improves dose distribution during hippocampal-sparing whole brain radiotherapy using VMAT

Abstract: Inclining the head position to approximately 11° during HS-WBRT using VMAT improved dose distribution in the planning target volume and allowed lower doses to the hippocampi and optic apparatus.

Cited by 12 publications

References 23 publications

Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost—tutorial and efficacy of complete directional hippocampal blocking

Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost—tutorial and efficacy of complete directional hippocampal blocking

Sparing the hippocampus and the hypothalamic- pituitary region during whole brain radiotherapy: a volumetric modulated arc therapy planning study

Hippocampus-sparing radiotherapy using volumetric modulated arc therapy (VMAT) to the primary brain tumor: the result of dosimetric study and neurocognitive function assessment

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