A dosimetric comparison of four treatment planning methods for high grade glioma

Zach, Leor; Stall, Bronwyn; Ning, Holly; Ondos, John; Arora, Barbara; Shankavaram, Uma; Miller, Robert W.; Citrin, Deborah E.; Camphausen, Kevin

doi:10.1186/1748-717x-4-45

Cited by 27 publications

(20 citation statements)

References 19 publications

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“…The aim of modern planning is not only to reduce the doses at the remaining normal brain and standard OAR, which has been correlated with different treatment methods [34], but also to spare sites where neurogenesis takes place, more specifically. However, an unsolved issue is the dose to be targeted at the hippocampus and the SVZ particularly according to the obviously multifactorial impairment of stem cell regeneration, in which corticoids and anticonvulsive drugs interfere with radiation [5].…”

Section: Discussionmentioning

confidence: 99%

Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

et al. 2013

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BackgroundNeurocognitive decline observed after radiotherapy (RT) for brain tumors in long time survivors is attributed to radiation exposure of the hippocampus and the subventricular zone (SVZ). The potential of sparing capabilities for both structures by optimized intensity modulated stereotactic radiotherapy (IMSRT) is investigated.MethodsBrain tumors were irradiated by stereotactic 3D conformal RT or IMSRT using m3 collimator optimized for PTV and for sparing of the conventional OARs (lens, retina, optic nerve, chiasm, cochlea, brain stem and the medulla oblongata). Retrospectively both hippocampi and SVZ were added to the list of OAR and their dose volume histograms were compared to those from two newly generated IMSRT plans using 7 or 14 beamlets (IMSRT-7, IMSRT-14) dedicated for optimized additional sparing of these structures. Conventional OAR constraints were kept constant. Impact of plan complexity and planning target volume (PTV) topography on sparing of both hippocampi and SVZ, conformity index (CI), the homogeneity index (HI) and quality of coverage (QoC) were analyzed. Limits of agreement were used to compare sparing of stem cell niches with either IMSRT-7 or IMSRT-14. The influence of treatment technique related to the topography ratio between PTV and OARs, realized in group A-D, was assessed by a mixed model.ResultsIn 47 patients CI (p ≤ 0.003) and HI (p < 0.001) improved by IMSRT-7, IMSRT-14, QoC remained stable (p ≥ 0.50) indicating no compromise in radiotherapy. 90% of normal brain was exposed to a significantly higher dose using IMSRT. IMSRT-7 plans resulted in significantly lower biologically effective doses at all four neural stem cell structures, while contralateral neural stem cells are better spared compared to ipsilateral. A further increase of the number of beamlets (IMSRT-14) did not improve sparing significantly, so IMSRT-7 and IMSRT-14 can be used interchangeable. Patients with tumors contacting neither the subventricular zone nor the cortex benefit most from IMSRT (p < 0.001).ConclusionThe feasibility of neural stem cell niches sparing with sophisticated linac based inverse IMSRT with 7 beamlets in an unselected cohort of intracranial tumors in relation to topographic situation has been demonstrated. Clinical relevance testing neurotoxicity remains to be demonstrated.

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Section: Discussionmentioning

confidence: 99%

Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

et al. 2013

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“…This was demonstrated by the isodose distributions and DVH curves. A number of studies have demonstrated a dosimetric benefit of different beam arrangement techniques in the brain tumors (Zach et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Assessment of brain dose distribution for ARC and conformal radiation therapy (CRT): A comparison study

Dawod

Omar

2015

Journal of Radiation Research and Applied Sciences

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a b s t r a c tObjective: This study evaluates the dose distribution of the three-dimensionally planned conformal radiation therapy (CRT) compared to the previously used (5 years ago) arc radiotherapy (ARCRT) of the brain cancer patients in Clinical Oncology and Nuclear Medicine Department e Mansoura University.Patients and methods: Thirty-three unselected brain cancer patients were planned by both the standard CRT and ARCRT techniques for radiotherapy of the brain. Doseevolume histograms were carried out by the 3D treatment planning system. They were assessed for the GTV, CTV, PTV and organs at risk. The prescribed total dose was 60 Gy in 30 fractions.Results: Comparing different DVHs, it was found that, the GTV, CTV and PTV were adequately covered in both (CRT & ARCRT) plans while it was demonstrated that ARCRT produced superior distribution compared to CRT technique, with considerable sparing of organ at risk. Conclusion:The tangential beam ARCRT planning demonstrated a significantly better homogeneity index for the GTV, CTV, and PTV of the brain cancer patients with a significant reduction in the mean doses of the both eyes, optic nerves, optic chiasm and brain stem.

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“…This result is not surprising because that study individually evaluated tumors in 3 different locations. Shaffer et al reported that VMAT had no statistical impact on PTV coverage, homogeneity or conformality, but did present significant sparing of selected OARs for complex glioblastomas [14], while others have reported that target coverage is better with more advanced techniques (tomotherapy) both in terms of PTV D95 and dose distribution homogeneity [18]. While dose constraints remained constant, the present utilization of 2 noncoplanar beam IMRT plans in addition to the IMRT 7 plan resulted in a lower mean CI in the IMRT 7 plan compared to the IMRT 7-non plan.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Multiple Treatment Planning Techniques for High-Grade Glioma Tumors Near to Critical Organs

Ayata¹,

Ceylan²,

Kilic³

et al. 2018

Oncol Res Treat

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Aim: The purpose of this study was to compare 6 treatment planning methods (5-beam coplanar intensity-modulated radiotherapy (IMRT), 7-beam coplanar IMRT, 7-beam noncoplanar IMRT, 2 full arc coplanar volumetric modulated arc therapy (VMAT), 2 half partial arc coplanar VMAT, and 2 half partial arc noncoplanar VMAT) for high-grade gliomas with planning target volumes (PTVs) overlapping the optic pathway and/or brainstem. Patients and Methods: 27 previously-treated patients with high-grade gliomas were replanned for treatment with IMRT₅, IMRT₇, IMRT_7-non, VMAT_2f, VMAT_2h, and VMAT_2h-non. In order to perform a comparative study of the treatment outcomes, 3 tumor localizations (right-sided, left-sided, and central tumors) were selected. Patients were administered a PTV dose of 60 Gy in 30 fractions with a maximum permitted dose of 110%. Results: Comparison of the 3 IMRT plans and 3 VMAT plans was performed for all 27 patients. The median conformity index was significantly higher (p < 0.05) in all IMRT plans compared to all VMAT plans in the case of right sided tumors. Significant differences were also observed between coplanar and noncoplanar plans in IMRT and VMAT in right-sided tumors (p < 0.05). Differences in brainstem mean doses were only found to be significant between coplanar and noncoplanar plans in centrally-located tumors. In right- and left-sided tumors, the VMAT_2f plans demonstrated higher values than all IMRT plans in their mean values for radiation doses to the ipsilateral optic nerves, contralateral optic nerves, ipsilateral lens, ipsilateral eye, contralateral lens, contralateral eye, and contralateral optic nerves, as well in the maximums for the optic chiasm and contralateral optic nerves. Significantly faster treatment times were achieved with all VMAT plans compared to IMRT plans. Conclusion: IMRT techniques provided better target coverage than VMAT plans. However, VMAT techniques reduced treatment delivery time more than IMRT techniques. Technique selection for tumors located in 3 different localizations should be individualized in accordance with patients' specific parameters.

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A dosimetric comparison of four treatment planning methods for high grade glioma

Cited by 27 publications

References 19 publications

Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

Assessment of brain dose distribution for ARC and conformal radiation therapy (CRT): A comparison study

Comparison of Multiple Treatment Planning Techniques for High-Grade Glioma Tumors Near to Critical Organs

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