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Dosimetric comparison of Acuros™ BV with AAPM TG43 dose calculation formalism in breast interstitial high-dose-rate brachytherapy with the use of metal catheters.

Sinnatamby M, Nagarajan V, Reddy K S, Karunanidhi G, Singhavajala V - J Contemp Brachytherapy (2015)

Bottom Line: This does not take into account tissue heterogeneity, attenuation and scatter in the metal applicator, and effects of patient boundary.Acuros™ BV is a Grid Based Boltzmann Solver code (GBBS), which takes into consideration all the above, was used to compute dosimetry and the two systems were compared.TG-43 algorithm seems to significantly overestimate the dose to various volumes of interest; GBBS based dose calculation algorithm has impact on CTV, heart, ipsilateral lung, heart, contralateral breast, skin, and ribs of the ipsilateral breast side; the prescription changes occurred due to effect of metal catheters, inhomogeneities, and scatter conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Regional Cancer Centre, JIPMER, Puducherry.

ABSTRACT

Purpose: Radiotherapy for breast cancer includes different techniques and methods. The purpose of this study is to compare dosimetric calculations using TG-43 dose formalism and Varian Acuros™ BV (GBBS) dose calculation algorithm for interstitial implant of breast using metal catheters in high-dose-rate (HDR) brachytherapy, using (192)Ir.

Material and methods: Twenty patients who were considered for breast conservative surgery (BCS), underwent lumpectomy and axillary dissection. These patients received perioperative interstitial HDR brachytherapy as upfront boost using rigid metal implants. Whole breast irradiation was delivered TG-43 after a gap of two weeks. Standard brachytherapy dose calculation was done by dosimetry. This does not take into account tissue heterogeneity, attenuation and scatter in the metal applicator, and effects of patient boundary. Acuros™ BV is a Grid Based Boltzmann Solver code (GBBS), which takes into consideration all the above, was used to compute dosimetry and the two systems were compared.

Results: Comparison of GBBS and TG-43 formalism on interstitial metal catheters shows difference in dose prescribed to CTV and other OARs. While the estimated dose to CTV was only marginally different with the two systems, there is a significant difference in estimated doses of starting from 4 to 53% in the mean value of all parameters analyzed.

Conclusions: TG-43 algorithm seems to significantly overestimate the dose to various volumes of interest; GBBS based dose calculation algorithm has impact on CTV, heart, ipsilateral lung, heart, contralateral breast, skin, and ribs of the ipsilateral breast side; the prescription changes occurred due to effect of metal catheters, inhomogeneities, and scatter conditions.

No MeSH data available.


Related in: MedlinePlus

Box and Whisker plot of comparison between Dmean and Dmax(A and B), V5% and V10%(C and D) of ipsilateral lung using 192Ir Acuros™ BV and 192Ir TG-43
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Figure 0005: Box and Whisker plot of comparison between Dmean and Dmax(A and B), V5% and V10%(C and D) of ipsilateral lung using 192Ir Acuros™ BV and 192Ir TG-43

Mentions: In ipsilateral lung, Acuros™ BV dose estimate for Dmean decreased by 5% (p = 0.007) and by 7% for Dmax. Both D2cc and D0.1cc show 7% reduction in the dose compared to TG-43 calculations. V5% and V10% had a greater reduction of 13% and 25% dose compared to TG-43 estimates. The Box and Whisker plot for Dmean, Dmax, V5% and V10% of the ipsilateral lung are shown in Figure 5. Due to the proximity of ribs to CTV, the contribution of dose to the ribs was included in the comparison. Acuros™ BV Dmean and Dmax values show a reduction of 11% and 5% compared to TG-43 dose values. The skin was demarcated as 5 mm from the surface on the ipsilateral breast area as skin contour. Acuros™ BV dose values show a reduction of 14% in Dmax and 11%in Dmean values computed by TG-43 dose formalism (Figure 6). D2cc and D0.1cc show a dose reduction of 5% compared to conventional TG-43 dose calculations.


Dosimetric comparison of Acuros™ BV with AAPM TG43 dose calculation formalism in breast interstitial high-dose-rate brachytherapy with the use of metal catheters.

Sinnatamby M, Nagarajan V, Reddy K S, Karunanidhi G, Singhavajala V - J Contemp Brachytherapy (2015)

Box and Whisker plot of comparison between Dmean and Dmax(A and B), V5% and V10%(C and D) of ipsilateral lung using 192Ir Acuros™ BV and 192Ir TG-43
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643735&req=5

Figure 0005: Box and Whisker plot of comparison between Dmean and Dmax(A and B), V5% and V10%(C and D) of ipsilateral lung using 192Ir Acuros™ BV and 192Ir TG-43
Mentions: In ipsilateral lung, Acuros™ BV dose estimate for Dmean decreased by 5% (p = 0.007) and by 7% for Dmax. Both D2cc and D0.1cc show 7% reduction in the dose compared to TG-43 calculations. V5% and V10% had a greater reduction of 13% and 25% dose compared to TG-43 estimates. The Box and Whisker plot for Dmean, Dmax, V5% and V10% of the ipsilateral lung are shown in Figure 5. Due to the proximity of ribs to CTV, the contribution of dose to the ribs was included in the comparison. Acuros™ BV Dmean and Dmax values show a reduction of 11% and 5% compared to TG-43 dose values. The skin was demarcated as 5 mm from the surface on the ipsilateral breast area as skin contour. Acuros™ BV dose values show a reduction of 14% in Dmax and 11%in Dmean values computed by TG-43 dose formalism (Figure 6). D2cc and D0.1cc show a dose reduction of 5% compared to conventional TG-43 dose calculations.

Bottom Line: This does not take into account tissue heterogeneity, attenuation and scatter in the metal applicator, and effects of patient boundary.Acuros™ BV is a Grid Based Boltzmann Solver code (GBBS), which takes into consideration all the above, was used to compute dosimetry and the two systems were compared.TG-43 algorithm seems to significantly overestimate the dose to various volumes of interest; GBBS based dose calculation algorithm has impact on CTV, heart, ipsilateral lung, heart, contralateral breast, skin, and ribs of the ipsilateral breast side; the prescription changes occurred due to effect of metal catheters, inhomogeneities, and scatter conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Regional Cancer Centre, JIPMER, Puducherry.

ABSTRACT

Purpose: Radiotherapy for breast cancer includes different techniques and methods. The purpose of this study is to compare dosimetric calculations using TG-43 dose formalism and Varian Acuros™ BV (GBBS) dose calculation algorithm for interstitial implant of breast using metal catheters in high-dose-rate (HDR) brachytherapy, using (192)Ir.

Material and methods: Twenty patients who were considered for breast conservative surgery (BCS), underwent lumpectomy and axillary dissection. These patients received perioperative interstitial HDR brachytherapy as upfront boost using rigid metal implants. Whole breast irradiation was delivered TG-43 after a gap of two weeks. Standard brachytherapy dose calculation was done by dosimetry. This does not take into account tissue heterogeneity, attenuation and scatter in the metal applicator, and effects of patient boundary. Acuros™ BV is a Grid Based Boltzmann Solver code (GBBS), which takes into consideration all the above, was used to compute dosimetry and the two systems were compared.

Results: Comparison of GBBS and TG-43 formalism on interstitial metal catheters shows difference in dose prescribed to CTV and other OARs. While the estimated dose to CTV was only marginally different with the two systems, there is a significant difference in estimated doses of starting from 4 to 53% in the mean value of all parameters analyzed.

Conclusions: TG-43 algorithm seems to significantly overestimate the dose to various volumes of interest; GBBS based dose calculation algorithm has impact on CTV, heart, ipsilateral lung, heart, contralateral breast, skin, and ribs of the ipsilateral breast side; the prescription changes occurred due to effect of metal catheters, inhomogeneities, and scatter conditions.

No MeSH data available.


Related in: MedlinePlus