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Single versus multichannel applicator in high-dose-rate vaginal brachytherapy optimized by inverse treatment planning.

Bahadur YA, Constantinescu C, Hassouna AH, Eltaher MM, Ghassal NM, Awad NA - J Contemp Brachytherapy (2014)

Bottom Line: For the organs-at-risk rectum and bladder, the use of multichannel applicator demonstrated a noticeable dose reduction, when compared to single channel, but statistically significant for rectum only (p = 0.0001).For D2cc of rectum, an average fractional dose of 6.1 ± 0.7 Gy resulted for single channel vs. 5.1 ± 0.6 Gy for multichannel.The dosimetric benefit of fractional re-planning was demonstrated: DVH analysis showed large, but not statistically significant differences between first fraction plan and fractional re-planning, due to large inter-fraction variations for rectum and bladder positioning and filling.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

ABSTRACT

Purpose: To retrospectively compare the potential dosimetric advantages of a multichannel vaginal applicator vs. a single channel one in intracavitary vaginal high-dose-rate (HDR) brachytherapy after hysterectomy, and evaluate the dosimetric advantage of fractional re-planning.

Material and methods: We randomly selected 12 patients with endometrial carcinoma, who received adjuvant vaginal cuff HDR brachytherapy using a multichannel applicator. For each brachytherapy fraction, two inverse treatment plans (for central channel and multichannel loadings) were performed and compared. The advantage of fractional re-planning was also investigated.

Results: Dose-volume-histogram (DVH) analysis showed limited, but statistically significant difference (p = 0.007) regarding clinical-target-volume dose coverage between single and multichannel approaches. For the organs-at-risk rectum and bladder, the use of multichannel applicator demonstrated a noticeable dose reduction, when compared to single channel, but statistically significant for rectum only (p = 0.0001). For D2cc of rectum, an average fractional dose of 6.1 ± 0.7 Gy resulted for single channel vs. 5.1 ± 0.6 Gy for multichannel. For D2cc of bladder, an average fractional dose of 5 ± 0.9 Gy occurred for single channel vs. 4.9 ± 0.8 Gy for multichannel. The dosimetric benefit of fractional re-planning was demonstrated: DVH analysis showed large, but not statistically significant differences between first fraction plan and fractional re-planning, due to large inter-fraction variations for rectum and bladder positioning and filling.

Conclusions: Vaginal HDR brachytherapy using a multichannel vaginal applicator and inverse planning provides dosimetric advantages over single channel cylinder, by reducing the dose to organs at risk without compromising the target volume coverage, but at the expense of an increased vaginal mucosa dose. Due to large inter-fraction dose variations, we recommend individual fraction treatment plan optimization.

No MeSH data available.


Related in: MedlinePlus

Dose distribution comparison between single channel (A) and multichannel (B), in axial and sagittal views. Isodose line of 7 Gy (prescribed dose) is displayed in yellow, 6.3 Gy (90% of prescribed dose) in green, 4.9 Gy (70% of prescribed dose) in pink and 14 Gy (200% of prescribed dose) in magenta. The capability of multichannel to correct for anisotropy at vaginal apex is clearly illustrated
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Figure 0001: Dose distribution comparison between single channel (A) and multichannel (B), in axial and sagittal views. Isodose line of 7 Gy (prescribed dose) is displayed in yellow, 6.3 Gy (90% of prescribed dose) in green, 4.9 Gy (70% of prescribed dose) in pink and 14 Gy (200% of prescribed dose) in magenta. The capability of multichannel to correct for anisotropy at vaginal apex is clearly illustrated

Mentions: A total of 22 paired HDR brachytherapy inverse plans were performed and analyzed. Dose distributions and DVHs were generated for the CTV and OARs for both the central channel and multichannel approaches for all patients. Figures 1 and 2 show a comparative example of single channel and multichannel approaches, for a representative patient. The comparison is performed with respect to the dose distribution (Fig. 1) and DVH (Fig. 2).


Single versus multichannel applicator in high-dose-rate vaginal brachytherapy optimized by inverse treatment planning.

Bahadur YA, Constantinescu C, Hassouna AH, Eltaher MM, Ghassal NM, Awad NA - J Contemp Brachytherapy (2014)

Dose distribution comparison between single channel (A) and multichannel (B), in axial and sagittal views. Isodose line of 7 Gy (prescribed dose) is displayed in yellow, 6.3 Gy (90% of prescribed dose) in green, 4.9 Gy (70% of prescribed dose) in pink and 14 Gy (200% of prescribed dose) in magenta. The capability of multichannel to correct for anisotropy at vaginal apex is clearly illustrated
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300361&req=5

Figure 0001: Dose distribution comparison between single channel (A) and multichannel (B), in axial and sagittal views. Isodose line of 7 Gy (prescribed dose) is displayed in yellow, 6.3 Gy (90% of prescribed dose) in green, 4.9 Gy (70% of prescribed dose) in pink and 14 Gy (200% of prescribed dose) in magenta. The capability of multichannel to correct for anisotropy at vaginal apex is clearly illustrated
Mentions: A total of 22 paired HDR brachytherapy inverse plans were performed and analyzed. Dose distributions and DVHs were generated for the CTV and OARs for both the central channel and multichannel approaches for all patients. Figures 1 and 2 show a comparative example of single channel and multichannel approaches, for a representative patient. The comparison is performed with respect to the dose distribution (Fig. 1) and DVH (Fig. 2).

Bottom Line: For the organs-at-risk rectum and bladder, the use of multichannel applicator demonstrated a noticeable dose reduction, when compared to single channel, but statistically significant for rectum only (p = 0.0001).For D2cc of rectum, an average fractional dose of 6.1 ± 0.7 Gy resulted for single channel vs. 5.1 ± 0.6 Gy for multichannel.The dosimetric benefit of fractional re-planning was demonstrated: DVH analysis showed large, but not statistically significant differences between first fraction plan and fractional re-planning, due to large inter-fraction variations for rectum and bladder positioning and filling.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

ABSTRACT

Purpose: To retrospectively compare the potential dosimetric advantages of a multichannel vaginal applicator vs. a single channel one in intracavitary vaginal high-dose-rate (HDR) brachytherapy after hysterectomy, and evaluate the dosimetric advantage of fractional re-planning.

Material and methods: We randomly selected 12 patients with endometrial carcinoma, who received adjuvant vaginal cuff HDR brachytherapy using a multichannel applicator. For each brachytherapy fraction, two inverse treatment plans (for central channel and multichannel loadings) were performed and compared. The advantage of fractional re-planning was also investigated.

Results: Dose-volume-histogram (DVH) analysis showed limited, but statistically significant difference (p = 0.007) regarding clinical-target-volume dose coverage between single and multichannel approaches. For the organs-at-risk rectum and bladder, the use of multichannel applicator demonstrated a noticeable dose reduction, when compared to single channel, but statistically significant for rectum only (p = 0.0001). For D2cc of rectum, an average fractional dose of 6.1 ± 0.7 Gy resulted for single channel vs. 5.1 ± 0.6 Gy for multichannel. For D2cc of bladder, an average fractional dose of 5 ± 0.9 Gy occurred for single channel vs. 4.9 ± 0.8 Gy for multichannel. The dosimetric benefit of fractional re-planning was demonstrated: DVH analysis showed large, but not statistically significant differences between first fraction plan and fractional re-planning, due to large inter-fraction variations for rectum and bladder positioning and filling.

Conclusions: Vaginal HDR brachytherapy using a multichannel vaginal applicator and inverse planning provides dosimetric advantages over single channel cylinder, by reducing the dose to organs at risk without compromising the target volume coverage, but at the expense of an increased vaginal mucosa dose. Due to large inter-fraction dose variations, we recommend individual fraction treatment plan optimization.

No MeSH data available.


Related in: MedlinePlus