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Equivalence of Gyn GEC-ESTRO guidelines for image guided cervical brachytherapy with EUD-based dose prescription.

Shaw W, Rae WI, Alber ML - Radiat Oncol (2013)

Bottom Line: Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria.The same was found for the tumor doses.The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Physics (G68), University of the Free State, Nelson Mandela Drive, Park West, Bloemfontein 9300, South Africa. shaww@ufs.ac.za.

ABSTRACT

Background: To establish a generalized equivalent uniform dose (gEUD) -based prescription method for Image Guided Brachytherapy (IGBT) that reproduces the Gyn GEC-ESTRO WG (GGE) prescription for cervix carcinoma patients on CT images with limited soft tissue resolution.

Methods: The equivalence of two IGBT planning approaches was investigated in 20 patients who received external beam radiotherapy (EBT) and 5 concomitant high dose rate IGBT treatments. The GGE planning strategy based on dose to the most exposed 2 cm3 (D2cc) was used to derive criteria for the gEUD-based planning of the bladder and rectum. The safety of gEUD constraints in terms of GGE criteria was tested by maximizing dose to the gEUD constraints for individual fractions.

Results: The gEUD constraints of 3.55 Gy for the rectum and 5.19 Gy for the bladder were derived. Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria. Average D2ccs and EUDs from the full treatment course were comparable for the two techniques within both sets of normal tissue constraints. The same was found for the tumor doses.

Conclusions: The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans. The gEUD-based planning considers the entire dose distribution of organs in contrast to a single dose-volume-histogram point.

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Related in: MedlinePlus

Total DVH parameters per patient. Total EQD2 for bladder (a) and rectum (b), and D90 for the HR- (c) and IR-CTV (d). Data are shown for the GGE technique (circles) and the CV technique (diamonds).
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Figure 3: Total DVH parameters per patient. Total EQD2 for bladder (a) and rectum (b), and D90 for the HR- (c) and IR-CTV (d). Data are shown for the GGE technique (circles) and the CV technique (diamonds).

Mentions: The two planning approaches were compared in terms of total dose from all 5 IGBT fractions plus the EBT component for the patients in the study. Very similar total dose parameters for the two techniques were found. Figure 3 displays the total dose in the two planning techniques for rectum and bladder D2cc, and HR- and IR-CTV D90. Figure 4 displays the rectal and bladder wall gEUDs, and the HR- and IR-CTV EUDs. Table 4 provides the average and standard deviations of their frequency distributions, indicating very similar means.


Equivalence of Gyn GEC-ESTRO guidelines for image guided cervical brachytherapy with EUD-based dose prescription.

Shaw W, Rae WI, Alber ML - Radiat Oncol (2013)

Total DVH parameters per patient. Total EQD2 for bladder (a) and rectum (b), and D90 for the HR- (c) and IR-CTV (d). Data are shown for the GGE technique (circles) and the CV technique (diamonds).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3842680&req=5

Figure 3: Total DVH parameters per patient. Total EQD2 for bladder (a) and rectum (b), and D90 for the HR- (c) and IR-CTV (d). Data are shown for the GGE technique (circles) and the CV technique (diamonds).
Mentions: The two planning approaches were compared in terms of total dose from all 5 IGBT fractions plus the EBT component for the patients in the study. Very similar total dose parameters for the two techniques were found. Figure 3 displays the total dose in the two planning techniques for rectum and bladder D2cc, and HR- and IR-CTV D90. Figure 4 displays the rectal and bladder wall gEUDs, and the HR- and IR-CTV EUDs. Table 4 provides the average and standard deviations of their frequency distributions, indicating very similar means.

Bottom Line: Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria.The same was found for the tumor doses.The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Physics (G68), University of the Free State, Nelson Mandela Drive, Park West, Bloemfontein 9300, South Africa. shaww@ufs.ac.za.

ABSTRACT

Background: To establish a generalized equivalent uniform dose (gEUD) -based prescription method for Image Guided Brachytherapy (IGBT) that reproduces the Gyn GEC-ESTRO WG (GGE) prescription for cervix carcinoma patients on CT images with limited soft tissue resolution.

Methods: The equivalence of two IGBT planning approaches was investigated in 20 patients who received external beam radiotherapy (EBT) and 5 concomitant high dose rate IGBT treatments. The GGE planning strategy based on dose to the most exposed 2 cm3 (D2cc) was used to derive criteria for the gEUD-based planning of the bladder and rectum. The safety of gEUD constraints in terms of GGE criteria was tested by maximizing dose to the gEUD constraints for individual fractions.

Results: The gEUD constraints of 3.55 Gy for the rectum and 5.19 Gy for the bladder were derived. Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria. Average D2ccs and EUDs from the full treatment course were comparable for the two techniques within both sets of normal tissue constraints. The same was found for the tumor doses.

Conclusions: The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans. The gEUD-based planning considers the entire dose distribution of organs in contrast to a single dose-volume-histogram point.

Show MeSH
Related in: MedlinePlus