Whole-brain hippocampal sparing radiation therapy: Volume-modulated arc therapy vs intensity-modulated radiation therapy case study

Lee, Katrina; Lenards, Nishele; Holson, Janice

doi:10.1016/j.meddos.2015.06.003

Cited by 21 publications

(19 citation statements)

References 5 publications

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“…In contrast to Fan et al, who were the first group describing a combined sparing approach of the hippocampus and the HT-P area using IMRT, we chose a VMAT approach. For hippocampal sparing during WBRT (without the HT-P area), the use of VMAT was shown to significantly improve dose distribution in terms of target coverage and homogeneity [26][27][28]. In the study of Sood et al, the use of a VMAT-technique also reduced mean and maximum doses to other organs at risk (OAR) such as cochleae and parotid glands [29].…”

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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“…Although advanced radiotherapy technologies, including IMRT and VMAT, have made it possible to spare the hippocampus during WBRT, delivering HS-WBRT is challenging, owing to the central location of the hippocampus within the brain. Lee et al have previously reported that compared to IMRT, VMAT treatment plans produced a more homogenous dose distribution and decreased the maximum point dose to the target [11]. In their study, non-coplanar arcs were used for VMAT, owing to limitations associated with the angle of the arc, which prevent direct irradiation to the lens and meeting the dose constraint.…”

Section: Discussionmentioning

confidence: 99%

“…Volumetric-modulated arc therapy (VMAT) is an advanced form of IMRT that delivers radiation dose with a 360-degree rotation of the gantry. Previous studies have shown that VMAT has dosimetric outcomes superior to IMRT in HS-WBRT [10,11]. Moreover, Sood et al have reported that VMAT could reduce irradiation dose to the hippocampus and other healthy organs, including the scalp, auditory canals, cochleae, and parotid gland [12].…”

Section: Introductionmentioning

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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“…More recently, volumetric modulated arc therapy (VMAT) has also been examined for HA-WBRT. 8 VMAT showed superior dosimetric performance to IMRT, 9,10 and can practically deliver dose painting in form of simultaneous integrated boost (SIB) 11 to multiple brain metastases, 12,13 along with HA-WBRT. 14,15 Dosimetric quality and efficiency for IMRT and VMAT were further promoted by a recent advancement in inverse planning technology: multi-criteria optimization (MCO).…”

Section: Introductionmentioning

confidence: 99%

Assessment of multi‐criteria optimization (MCO) for volumetric modulated arc therapy (VMAT) in hippocampal avoidance whole brain radiation therapy (HA‐WBRT)

Zieminski

Khandekar

Wang

2018

J Applied Clin Med Phys

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This study compared the dosimetric performance of (a) volumetric modulated arc therapy (VMAT) with standard optimization (STD) and (b) multi‐criteria optimization (MCO) to (c) intensity modulated radiation therapy (IMRT) with MCO for hippocampal avoidance whole brain radiation therapy (HA‐WBRT) in RayStation treatment planning system (TPS). Ten HA‐WBRT patients previously treated with MCO‐IMRT or MCO‐VMAT on an Elekta Infinity accelerator with Agility multileaf collimators (5‐mm leaves) were re‐planned for the other two modalities. All patients received 30 Gy in 15 fractions to the planning target volume (PTV), namely, PTV30 expanded with a 2‐mm margin from the whole brain excluding hippocampus with margin. The patients all had metastatic lesions (up to 12) of variable sizes and proximity to the hippocampus, treated with an additional 7.5 Gy from a simultaneous integrated boost (SIB) to PTV37.5. The IMRT plans used eight to eleven non‐coplanar fields, whereas the VMAT plans used two coplanar full arcs and a vertex half arc. The averaged target coverage, dose to organs‐at‐risk (OARs) and monitor unit provided by the three modalities were compared, and a Wilcoxon signed‐rank test was performed. MCO‐VMAT provided statistically significant reduction of D100 of hippocampus compared to STD‐VMAT, and Dmax of cochleas compared to MCO‐IMRT. With statistical significance, MCO‐VMAT improved V30 of PTV30 by 14.2% and 4.8%, respectively, compared to MCO‐IMRT and STD‐VMAT. It also raised D95 of PTV37.5 by 0.4 Gy compared to both MCO‐IMRT and STD‐VMAT. Improved plan quality parameters such as a decrease in overall plan Dmax and total monitor units (MU) were also observed for MCO‐VMAT. MCO‐VMAT is found to be the optimal modality for HA‐WBRT in terms of PTV coverage, OAR sparing and delivery efficiency, compared to MCO‐IMRT or STD‐VMAT.

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Whole-brain hippocampal sparing radiation therapy: Volume-modulated arc therapy vs intensity-modulated radiation therapy case study

Cited by 21 publications

References 5 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

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)

Assessment of multi‐criteria optimization (MCO) for volumetric modulated arc therapy (VMAT) in hippocampal avoidance whole brain radiation therapy (HA‐WBRT)

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