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Different intensity extension methods and their impact on entrance dose in breast radiotherapy: A study.

Sankar A, Velmurugan J - J Med Phys (2009)

Bottom Line: The impact of these two different intensity extension methods on skin dose was studied by measuring the entrance dose of the treatment fields using semiconductor diode detectors.We found no significant difference in entrance dose due to different methods used for intensity extension.However, in the skin flash tool method, selection of appropriate parameters is important to get optimum fluence extension.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Therapy, Salmaniya Medical Complex, Salmaniya, Kingdom of Bahrain.

ABSTRACT
In breast radiotherapy, skin flashing of treatment fields is important to account for intrafraction movements and setup errors. This study compares the two different intensity extension methods, namely, Virtual Bolus method and skin flash tool method, to provide skin flashing in intensity modulated treatment fields. The impact of these two different intensity extension methods on skin dose was studied by measuring the entrance dose of the treatment fields using semiconductor diode detectors. We found no significant difference in entrance dose due to different methods used for intensity extension. However, in the skin flash tool method, selection of appropriate parameters is important to get optimum fluence extension.

No MeSH data available.


Related in: MedlinePlus

Dose Volume Histograms (DVH) of target volume obtained from different tangential pair plans
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Figure 0006: Dose Volume Histograms (DVH) of target volume obtained from different tangential pair plans

Mentions: PTV DVHs that resulted from tangential pair plans and multiple field IMRT plans are shown in figure 5 and 6 respectively. Generally the PTV dose coverage was better in IMRT plans compared to the tangential wedge pair and segmented beam plans. The volume receiving high dose was significantly less in IMRT plans compared to tangential wedge pair and segmented beam plans. The PTV dose coverage and the dose homogeneity are marginally better in the virtual bolus method compared to plans without extension and skin flash tool method [Figure 5]. The reason for this is, in the virtual bolus method the optimum intensity is decided by the iterative process in the extension region, whereas in the skin flash tool method the extension is taken from five mm inside the field edge, which could result in high dose region near the surface. Multiple beam IMRT plans also show a similar trend [Figure 6] but the magnitude of difference is insignificant.


Different intensity extension methods and their impact on entrance dose in breast radiotherapy: A study.

Sankar A, Velmurugan J - J Med Phys (2009)

Dose Volume Histograms (DVH) of target volume obtained from different tangential pair plans
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807141&req=5

Figure 0006: Dose Volume Histograms (DVH) of target volume obtained from different tangential pair plans
Mentions: PTV DVHs that resulted from tangential pair plans and multiple field IMRT plans are shown in figure 5 and 6 respectively. Generally the PTV dose coverage was better in IMRT plans compared to the tangential wedge pair and segmented beam plans. The volume receiving high dose was significantly less in IMRT plans compared to tangential wedge pair and segmented beam plans. The PTV dose coverage and the dose homogeneity are marginally better in the virtual bolus method compared to plans without extension and skin flash tool method [Figure 5]. The reason for this is, in the virtual bolus method the optimum intensity is decided by the iterative process in the extension region, whereas in the skin flash tool method the extension is taken from five mm inside the field edge, which could result in high dose region near the surface. Multiple beam IMRT plans also show a similar trend [Figure 6] but the magnitude of difference is insignificant.

Bottom Line: The impact of these two different intensity extension methods on skin dose was studied by measuring the entrance dose of the treatment fields using semiconductor diode detectors.We found no significant difference in entrance dose due to different methods used for intensity extension.However, in the skin flash tool method, selection of appropriate parameters is important to get optimum fluence extension.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Therapy, Salmaniya Medical Complex, Salmaniya, Kingdom of Bahrain.

ABSTRACT
In breast radiotherapy, skin flashing of treatment fields is important to account for intrafraction movements and setup errors. This study compares the two different intensity extension methods, namely, Virtual Bolus method and skin flash tool method, to provide skin flashing in intensity modulated treatment fields. The impact of these two different intensity extension methods on skin dose was studied by measuring the entrance dose of the treatment fields using semiconductor diode detectors. We found no significant difference in entrance dose due to different methods used for intensity extension. However, in the skin flash tool method, selection of appropriate parameters is important to get optimum fluence extension.

No MeSH data available.


Related in: MedlinePlus