Dosimetric evaluation of four whole brain radiation therapy approaches with hippocampus and inner ear avoidance and simultaneous integrated boost for limited brain metastases

Jiang, An; Sun, Wei; Zhao, Fen; Wu, Zhonghu; Shang, Dan; Yu, Qingxi; Wang, Shuzhen; Zhu, Jian; Yang, Feng-chang; Yuan, Shuanghu

doi:10.1186/s13014-019-1255-7

Cited by 27 publications

(26 citation statements)

References 33 publications

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“…For hippocampal sparing in WBRT, slightly superior homogeneity indices and target coverage were found for tomotherapy when compared to IMRT and VMAT [31,32]. However, the availability of tomotherapy is limited, and the treatment planning time is significantly longer.…”

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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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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“…In our study, in the comparison of two modalities (VMAT and helical tomotherapy), it is seen that the average of minimum, mean and maximum doses received by both right and left hippocampal regions are lower in helical tomotherapy treatment planning system (TPS). Also, they concluded that the inner ear dose was reduced to Dmean ≤15Gy in all four planning modalities (27) .…”

Section: Discussionmentioning

confidence: 98%

“…In their study, Jiang et al showed that 4 planning modalities (sIMRT, dIMRT, VMAT and Tomo) satisfied the RTOG 0933 protocol dose compatibility criteria for hippocampal sparing. Using the planning modalities reported above with an acceptable mean PTV brain coverage (88.2%-92.6), delivery of similar mean doses to the hippocampi were accomplished (27) . In our study, in the comparison of two modalities (VMAT and helical tomotherapy), it is seen that the average of minimum, mean and maximum doses received by both right and left hippocampal regions are lower in helical tomotherapy treatment planning system (TPS).…”

Section: Discussionmentioning

confidence: 99%

Dosimetric Comparison of Volumetric Modulated Arc Therapy and Helical Tomotherapy for Hippocampal-Avoidance Prophylactic Whole Brain Radiotherapy(HA-PWBRT) in Small Cell Lung Cancer;Treatment Plans Based Study

Doğan¹,

Çini²,

Can³

2020

BMJ

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Objective: To carry out a dosimetric evaluation of two different advanced radiotherapy modalities prophylactic-whole brain radiotherapy with hippocampal avoidance in the treatment of patients with small cell lung cancer (SCLC). Method: Computed tomography with fused magnetic resonance images of patients who were diagnosed with SCLC without brain metastasis were combined and re-planned with volumetric-modulated arc (VMAT) and also helical tomotherapy (n=10). Doses of 25 Gy were prescribed in 10 fractions for the whole brain volume. Planning was performed according to RTOG 0933 criteria for hippocampal avoidance (Dmax ≤16Gy, D100% ≤9Gy). Planning target volume (PTV), homogeneity index (HI), conformity index (CI), minimum dose (Dmin) maximum dose (Dmax) and dose for organs at risk (OARs) were compared. Results: In the analysis of PTV data, no significant difference was found between the helical tomotherapy and VMAT for D95 values, the minimum, maximum and mean values of PTV brain doses were higher in the VMAT arm (p=0,000). When comparing PTV HI and CI values, VMAT was significantly superior in CI value (p=0.033), but there was no significant superiority in HI values (p=0.499). When compared statistically, and radiation doses delivered to hippocampus were evaluated it was seen that helical tomotherapy provided significantly better hippocampal protection than

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“…To reduce the risk of cognitive decline and improve clinical outcomes, attempts have been made at adding simultaneous integrated boost (SIB) to HS-WBRT. For example, Jiang et al have demonstrated that HS-WBRT with SIB can be implemented using four modern RT techniques, including step-and-shoot IMRT, dynamic IMRT, VMAT, and helical tomotherapy [26]. Specifically, they prescribed 45-50 Gy to metastatic lesion, and 30 Gy to the whole brain, in 10 fractions.…”

Section: Plos Onementioning

confidence: 99%

Use of a head-tilting baseplate during volumetric-modulated arc therapy (VMAT) to better protect organs at risk in hippocampal sparing whole brain radiotherapy (HS-WBRT)

Yea

Park

2020

PLoS ONE

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Coplanar arcs are used with limited arc range to prevent direct beam entrance through the lens, which is challenging for satisfactory planning of hippocampal sparing in whole brain radiotherapy (HS-WBRT) with VMAT. We evaluated the dosimetric impact of applying a head-tilting technique during VMAT, which allows unrestricted use of the arc range. Methods and materials Twenty patients with multiple brain metastases who had received two computed tomography (CT)-simulation sessions between January 2016 and December 2018 were included. One session was delivered in a traditional supine position; the other was delivered with a tilting acrylic supine baseplate (MedTec, USA) to elevate the patients' head by 40˚. For each patient, a VMAT without (sVMAT) and with head-tilting (htVMAT) plan was generated. Conformity index (CI), homogeneity index (HI), and organ at risk (OAR) dose were evaluated. The Wilcoxon-signed test was used to compare the effect between two plans. Results The mean CI was 0.860±0.007 and 0.864±0.008 (p<0.05), and mean HI was 0.179±0.020 and 0.167±0.021 (p<0.05) for sVMAT and htVMAT, respectively. The mean dose to the hippocampus (9.91±0.30 Gy) was significantly lower in htVMAT than in sVMAT (10.36±0.29 Gy, P<0.05). htVMAT was associated with significantly reduced mean dose to the parotid gland, and right and left lens (4.77±1.97 Gy vs. 5.92±1.

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Dosimetric evaluation of four whole brain radiation therapy approaches with hippocampus and inner ear avoidance and simultaneous integrated boost for limited brain metastases

Cited by 27 publications

References 33 publications

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

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

Dosimetric Comparison of Volumetric Modulated Arc Therapy and Helical Tomotherapy for Hippocampal-Avoidance Prophylactic Whole Brain Radiotherapy(HA-PWBRT) in Small Cell Lung Cancer;Treatment Plans Based Study

Use of a head-tilting baseplate during volumetric-modulated arc therapy (VMAT) to better protect organs at risk in hippocampal sparing whole brain radiotherapy (HS-WBRT)

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