Dosimetric and Radiobiological Impact of Flattening Filter‐Free Beam and Dose Calculation Algorithm Using RapidArc Plans for Cervical Cancer Treatment

Manna, Sumanta; Singh, Sharad; Gupta, Pramod Kumar; T, Ragul

doi:10.1002/pro6.1207

Cited by 2 publications

(1 citation statement)

References 31 publications

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“…Achieving this dose fall-off and optimizing the protection of normal tissues involves employing techniques such as eliminating the body from targets or inserting multiple rings radially around the target. 9,10 Although it is effective, the use of ring structures increases planning time. Creating a ring structure is time-consuming and creates the additional challenge of choosing the number of rings, ring width, gaps or overlaps, and the associated penalty priorities.…”

Section: Introductionmentioning

confidence: 99%

Assessment of normal tissue objectives in RapidArc treatment for cervical cancer

P.,

Manna,

Singh

2024

J Radiother Pract

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Purpose: The normal tissue objective (NTO) is a tool used in inverse-planned intensity-modulated radiation therapy (IMRT) to minimize dose dispersion to surrounding tissues. The current study focuses on the NTO’s impact on RapidArc treatment plans for cervical cancer patients or its role in reducing doses to healthy surrounding tissues. Material and methods: This study included 11 cervical cancer patients who underwent RapidArc treatment. We assessed plans both with and without the NTO objective by evaluating parameters such as homogeneity, conformity, gradient index (GI), IMRT factor, integral dose and the volume of normal tissues receiving low doses of 40, 30, 20 and 10 Gy. Further, differences between automatic NTO and manual NTO were evaluated using Wilcoxon signed-rank test. Results: There were no significant differences in the conformity index, homogeneity index, IMRT factor and integral dose between plans with automatic NTO and those with manual NTO RapidArc plans. However, we did observe a clear advantage in using manual NTO for controlling low-dose exposure to normal tissues. The comparisons between automatic and manual NTO resulted in a GI of 3·1 ± 0·3 versus 2·7 ± 0·68 (p = 0·008). Furthermore, we noticed a significant reduction in the volumes receiving low doses (V10, V20, V30 and V40) with the manual NTO settings. Conclusion: The NTO plays a crucial role in optimizing RapidArc plans for treating cervical cancer. Based on the findings of this study, manual NTO settings of distance from PTV border xstart = 0·5 mm, start dose f0 = 105%, end dose f∞ = an average of 40%, dose fall-off 0·2 mm–1 were optimal. Further research involving a larger sample size and exploration of various NTO parameters is necessary to validate our results.

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Section: Introductionmentioning

confidence: 99%

Assessment of normal tissue objectives in RapidArc treatment for cervical cancer

P.,

Manna,

Singh

2024

J Radiother Pract

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Fluence smoothing evaluation for whole‐breast automatically generated treatment plans

Zaratim,

Oliveira e Silva,

dos Reis

et al. 2024

J Applied Clin Med Phys

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PurposeThis study aimed to identify the fluence smoothing threshold that preserves the dosimetric quality of planning for breast cancer intensity‐modulated radiation therapy (IMRT).Material and methodsWe conducted automated treatment planning for 60 breast cancer patients using the Eclipse Scripting Application Programming Interface. The plans included four‐field IMRT, emphasizing smoothing weight combinations while maintaining a 4:3 aspect ratio between the X and Y directions. Four weight sets (40 × 30, 100 × 75, 150 × 115.2, and 200 × 150) were tested, resulting in four plans per patient. A total dose of 40.05 Gy over 15 fractions was prescribed. Optimization weigths were dynamically adjusted based on dosimetric evaluations, with the maximum coverage priority set at 200. Statistical analyses were used to assess the dosimetric data.ResultsThe median planning target volume (PTV) coverage varied across smoothing levels, with default smoothing (40 × 30) providing superior median PTV coverage. Lung constraints showed significant differences mainly at higher smoothing levels. Heart constraints exhibited less variation between smoothing levels, with significant differences primarily in the maximum and mean doses for right‐sided patients and between default and higher smoothing levels for left‐sided patients. No significant differences were observed in contralateral breast constraints among all smoothing levels, except at the maximum level for right‐sided patients. Monitor units decreased with increasing smoothing weight, showing significant differences between default and other settings. For right‐sided patients, the median number of monitor units varied from 1346 (40 × 30) to 754 (200 × 150), and for left‐sided patients, from 1333 (40 × 30) to 804 (200 × 150). Chi‐square tests revealed differences in dose constraint adherence between default and maximum smoothing levels, particularly in target coverage.ConclusionOur findings suggest that using a ratio of smoothing weights to target priorities between 1:1.5 and 1:1.6 leads to a favorable balance between complexity and dosimetric plan quality, with no significant impacts on dose constraint adherence.

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Dosimetric and Radiobiological Impact of Flattening Filter‐Free Beam and Dose Calculation Algorithm Using RapidArc Plans for Cervical Cancer Treatment

Cited by 2 publications

References 31 publications

Assessment of normal tissue objectives in RapidArc treatment for cervical cancer

Assessment of normal tissue objectives in RapidArc treatment for cervical cancer

Fluence smoothing evaluation for whole‐breast automatically generated treatment plans

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