The effect of gantry spacing resolution on plan quality in a single modulated arc optimization

Mihaylov, Ivaylo B.; Curran, Bruce; Sternick, Edward S.

doi:10.1120/jacmp.v12i4.3603

Cited by 8 publications

(14 citation statements)

References 28 publications

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“…In Pinnacle, 2º, 3º, or 4º spacing is often used in the angle spatial resolution. It appears that 4ºCP spacing may be a good compromise between calculation speed and accuracy for the SmartArc plans delivered on Varian machines (Feygelman, Zhang, & Stevens, 2010;Mihaylov, Curran, & Sternick, 2011). The results of this study indicate that the Monaco TPS requires a relatively large IG (30º or 40º) during VMAT planning, and a smaller IG value will reduce the plan quality.…”

Section: Discussionmentioning

confidence: 84%

The influence of increment of gantry on VMAT plan quality for cervical cancer

Chen

et al. 2019

Journal of Radiation Research and Applied Sciences

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This study aimed to assess the influence of increment of gantry (IG) value on plan quality among cervical cancer patients treated with volumetric modulated arc therapy (VMAT). Twenty postoperative cervical cancer patients receiving radiotherapy were selected. Four different VMAT plans were designed in Monaco TPS using the same optimization conditions but with varying IG parameters (10°, 20°, 30°, and 40°). The IG10 group did not meet the clinical requirements. The target dose of the IG20 group was slightly worse than that of IG30 and IG40 groups; the differences in dose distribution in organs at risk among the IG20, IG30, and IG40 groups were negligible. The average monitoring units of the IG20, IG30, and IG40 groups were 704.6, 594.6, and 572.6, and the average control points of the three groups were 134.4, 139.4, and 140.3, respectively. The plan delivery times of the three groups were 117.6 s, 111.0 s, and 118.1 s, respectively. At a 3% dose difference and a 3 mm distance to agreement, the gamma pass rates of the IG20, IG30, and IG40 plans were 99.1%, 99.6%, and 99.4%, respectively. Considering the plan quality, the dose accuracy, and delivery efficiency, IG30 is recommended for cervical cancer VMAT planning.

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Section: Discussionmentioning

confidence: 84%

The influence of increment of gantry on VMAT plan quality for cervical cancer

Chen

et al. 2019

Journal of Radiation Research and Applied Sciences

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“…Also, the leaf motion was not constrained beyond the default limits of the modeled linear accelerator. It is possible that adjusting these specific optimization parameters may diminish KBP plan complexity and delivery accuracy deficiencies to an extent . Another potential limitation is that only a limited number of metrics were chosen to quantify plan complexity, though the chosen metrics are commonly used in the literature …”

Section: Discussionmentioning

confidence: 99%

Evaluation of complexity and deliverability of prostate cancer treatment plans designed with a knowledge‐based VMAT planning technique

Wall

Fontenot

2019

J Applied Clin Med Phys

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Purpose: Knowledge-based planning (KBP) techniques have been reported to improve plan quality, efficiency, and consistency in radiation therapy. However, plan complexity and deliverability have not been addressed previously for treatment plans guided by an established in-house KBP system. The purpose of this work was to assess dosimetric, mechanical, and delivery properties of plans designed with a common KBP method for prostate cases treated via volumetric modulated arc therapy (VMAT).Methods: Thirty-one prostate patients previously treated with VMAT were replanned with an in-house KBP method based on the overlap volume histogram.VMAT plan complexities of the KBP plans and the reference clinical plans were quantified via monitor units, modulation complexity scores, the edge metric, and average leaf motion per degree of gantry rotation. Each set of plans was delivered to the same diode array and agreement between computed and measured dose distributions was evaluated using the gamma index. Varying percent dose-difference (1-3%) and distance-to-agreement (1 mm to 3 mm) thresholds were assessed for gamma analyses.Results: Knowledge-based planning (KBP) plans achieved average reductions of 6.4 Gy (P < 0.001) and 8.2 Gy (P < 0.001) in mean bladder and rectum dose compared to reference plans, while maintaining clinically acceptable target dose. However, KBP plans were significantly more complex than reference plans in each evaluated metric (P < 0.001). KBP plans also showed significant reductions (P < 0.05) in gamma passing rates at each evaluated criterion compared to reference plans.Conclusions: While KBP plans had significantly reduced bladder and rectum dose, they were significantly more complex and had significantly worse quality assurance outcomes than reference plans. These results suggest caution should be taken when implementing an in-house KBP technique. K E Y W O R D Sknowledge-based planning, quality assurance outcomes, treatment plan complexity, VMAT

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“…Many authors have studied the influence of different physics and machine parameters on the VMAT plan quality using Pinnacle and Eclipse planning system. [ 4 5 ] We carried out our study on Monaco planning system to analyze the influence of Some of the physical parameters on VMAT plan quality.…”

Section: Introductionmentioning

confidence: 99%

Influence of increment of gantry angle and number of arcs on esophageal volumetric modulated arc therapy planning in Monaco planning system: A planning study

Nithya¹,

Raj

Rathinamuthu³

et al. 2014

J Med Phys

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The objective of this study was to analyze the influence of the increment of gantry angle and the number of arcs on esophageal volumetric modulated arc therapy plan. All plans were done in Monaco planning system for Elekta Synergy linear accelerator with 80 multileaf collimator (MLC). Volumetric modulated arc therapy (VMAT) plans were done with different increment of gantry angle like 15°, 20°, 30° and 40°. The remaining parameters were similar for all the plans. The results were compared. To compare the plan quality with number of arcs, VMAT plans were done with single and dual arc with increment of gantry angle of 20°. The dose to gross tumor volume (GTV) for 60 Gy and planning target volume (PTV) for 48 Gy was compared. The dosimetric parameters D98%, D95%, D50% and Dmax of GTV were analyzed. The homogeneity index (HI) and conformity index (CI) of GTV were studied and the dose to 98% and 95% of PTV was analyzed. Maximum dose to spinal cord and planning risk volume of cord (PRV cord) was compared. The Volume of lung receiving 10 Gy, 20 Gy and mean dose was analyzed. The volume of heart receiving 30 Gy and 45 Gy was compared. The volume of normal tissue receiving greater than 2 Gy and 5 Gy was compared. The number of monitor units (MU) required to deliver the plans were compared. The plan with larger increment of gantry angle proved to be superior to smaller increment of gantry angle plans in terms of dose coverage, HI, CI and normal tissue sparing. The number of arcs did not make any difference in the quality of the plan.

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The effect of gantry spacing resolution on plan quality in a single modulated arc optimization

Cited by 8 publications

References 28 publications

The influence of increment of gantry on VMAT plan quality for cervical cancer

The influence of increment of gantry on VMAT plan quality for cervical cancer

Evaluation of complexity and deliverability of prostate cancer treatment plans designed with a knowledge‐based VMAT planning technique

Influence of increment of gantry angle and number of arcs on esophageal volumetric modulated arc therapy planning in Monaco planning system: A planning study

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