A Dose Gradient Index for Stereotactic Radiosurgery/Radiotherapy: Evaluated with Helical Tomotherapy

Sheth, N; Sim, S.; Cheng, Jui-Chen; Lustgarten, Jack A.; Estin, D.; Olson, Terrah J. Paul; Weiss, Mona; Murphy, S; Chen, Y.; Yang, Jack

doi:10.1016/j.ijrobp.2011.06.1546

Cited by 5 publications

(3 citation statements)

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“…In Equation (1), the optimal value of HI is equal to 0 (i.e., D 5% = D 95% ). The GI is defined as: 28 where V 50% and V 100% are the volumes covered by at least 50 and 100% of the prescribed dose, respectively. A GI value closer to 1 embodies a faster dose fall-off in normal tissue, which may indicate a lower dose to the critical structure.…”

Section: Methodsmentioning

confidence: 99%

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Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

et al. 2016

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BackgroundWe demonstrated that our proposed planning target volume (PTV) dose–volume factor (PDVF) can be used to evaluate the PTV dose coverage between the intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans based on 90 prostate patients.PurposePDVF were determined from the prostate IMRT and VMAT plans to compare their variation of PTV dose coverage. Comparisons of the PDVF with other plan evaluation parameters such as D5%, D95%, D99%, Dmean, conformity index (CI), homogeneity index (HI), gradient index (GI) and prostate tumour control probability (TCP) were carried out.Methods and materialsProstate IMRT and VMAT plans using the 6 MV photon beams were created from 40 and 50 patients, respectively. Dosimetric indices (CI, HI and GI), dose–volume points (D5%, D95%, D99% and Dmean) and prostate TCP were calculated according to the PTV dose–volume histograms (DVHs) of the plans. All PTV DVH curves were fitted using the Gaussian error function (GEF) model. The PDVF were calculated based on the GEF parameters.ResultsFrom the PTV DVHs of the prostate IMRT and VMAT plans, the average D99% of the PTV for IMRT and VMAT were 74·1 and 74·5 Gy, respectively. The average prostate TCP were 0·956 and 0·958 for the IMRT and VMAT plans, respectively. The average PDVF of the IMRT and VMAT plans were 0·970 and 0·983, respectively. Although both the IMRT and VMAT plans showed very similar prostate TCP, the dosimetric and radiobiological results of the VMAT technique were slightly better than IMRT.ConclusionThe calculated PDVF for the prostate IMRT and VMAT plans agreed well with other dosimetric and radiobiological parameters in this study. PDVF was verified as an alternative of evaluation parameter in the quality assurance of prostate treatment planning.

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Section: Methodsmentioning

confidence: 99%

“…In Equation 1, the optimal value of HI is equal to 0 (i.e., D 5% = D 95% ). The GI is defined as: 28…”

Section: Calculations Of the CI Hi And Gimentioning

confidence: 99%

Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

et al. 2016

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“…Measuring the dose gradient and comparing it between rival plans and various treatment modalities have attracted a huge deal of interest in the radiation oncology society. Several studies [11,[13][14][15][16] have introduced different gradient indices to achieve the dose fall-off rate near the target volume. Sung et al [17] represented a new dose gradient that was comprehensive and appropriate for clinical practice.…”

Section: Introductionmentioning

confidence: 99%

Investigating the number of radiation fields in intensity-modulated radiotherapy plans of optic nerve sheath meningioma patients using dose gradient index

Mazloomi

Abedi

Shanei

et al. 2022

Biomed. Phys. Eng. Express

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Purpose: In optic nerve radiotherapy, vital organs are very close to the target volume, they are highly sensitive to radiation and have low dose tolerance. In this regard, evaluating dose fall-off steepness around the target volume is required to assess various intensity-modulated radiation therapy (IMRT) plans in the treatment of the optic nerve sheath meningioma (ONSM) patients. Materials and Methods: Thirteen ONSM patients were analyzed with three IMRT techniques, including three (IMRT-3F), five (IMRT-5F), and seven fields (IMRT-7F). These plans were studied using Dmean, Dmax, D2%, D98%, V100%, uniformity index (UI), homogeneity index (HI), conformity index (CI), and specifically the dose gradient indices (DGIs). Results: The values of Dmax and Dmean for IMRT-3F, IMRT-5F and IMRT-7F were (5637.42 ± 57.08, 5322.84 ± 83.86), (5670.51 ± 67.87, 5383.00 ± 58.45), and (5692.99 ± 31.65, 5405.72 ± 51.73), respectively, which were increased with increment in the number of IMRT fields from 3 to 7. The UI and HI indices were significantly different between IMRT-3F and IMRT-7F (p=0.010 and p=0.005, respectively), and CI was close to the ideal value (0.99±0.01) in IMRT-7F. The significant findings of the dose gradient indices represented smaller values in IMRT-7F, which led to a faster dose fall-off, particularly at the 70%-85% isodose levels around the target. Conclusion: Increasing the number of radiation fields in IMRT treatment plans of ONSM patients had a considerable difference in both the dosimetric parameters of the target volume and at-risk organs, as well as the dose gradient indices. Overall, IMRT-7F could be considered as a preferred technique in the treatment of this meningioma.

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Quantitative assessment of the efficacy of two different treatment plan optimization algorithms in treating tumors in locations of high heterogeneity

et al. 2019

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A Dose Gradient Index for Stereotactic Radiosurgery/Radiotherapy: Evaluated with Helical Tomotherapy

Cited by 5 publications

References 0 publications

Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

Investigating the number of radiation fields in intensity-modulated radiotherapy plans of optic nerve sheath meningioma patients using dose gradient index

Quantitative assessment of the efficacy of two different treatment plan optimization algorithms in treating tumors in locations of high heterogeneity

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