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Dosimetric Effects of the Interfraction Variations during Whole Breast Radiotherapy: A Prospective Study.

Jacob J, Heymann S, Borget I, Dumas I, Riahi E, Maroun P, Ezra P, Roberti E, Rivera S, Deutsch E, Bourgier C - Front Oncol (2015)

Bottom Line: Daily movements were applied to the baseline treatment planning (TP1) to design a further TP (TP2).A total of 241 portal images were analyzed.The random and systematic errors were 2.6 and 3.7 mm for the CLD, 4.3 and 6.9 mm for the ICM, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Gustave Roussy , Villejuif , France.

ABSTRACT

Introduction: The aim of this work was to assess the dosimetric impact of the interfraction variations during breast radiotherapy.

Materials and methods: Daily portal imaging measurements were prospectively performed in 10 patients treated with adjuvant whole breast irradiation (50 Gy/25 fractions). Margins between the clinical target volume and the planning target volume (PTV) were 5 mm in the three dimensions. Parameters of interest were the central lung distance (CLD) and the inferior central margin (ICM). Daily movements were applied to the baseline treatment planning (TP1) to design a further TP (TP2). The PTV coverage and organ at risk exposure were measured on both TP1 and TP2, before being compared.

Results: A total of 241 portal images were analyzed. The random and systematic errors were 2.6 and 3.7 mm for the CLD, 4.3 and 6.9 mm for the ICM, respectively. No significant consequence on the PTV treatments was observed (mean variations: +0.1%, p = 0.56 and -1.8%, p = 0.08 for the breast and the tumor bed, respectively). The ipsilateral lung and heart exposure was not significantly modified.

Conclusion: In our series, the daily interfraction variations had no significant effect on the PTV coverage or healthy tissue exposure during breast radiotherapy.

No MeSH data available.


Related in: MedlinePlus

Description of the inferior central margin and central lung distance on a digital reconstructed radiography performed on the treatment planning system Isogray® according to Fein et al. (6) and Kong et al. (10). The nipple and the surgical scar are, respectively, delineated in yellow and purple. CLD, central lung distance; ICM, inferior central margin.
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Figure 1: Description of the inferior central margin and central lung distance on a digital reconstructed radiography performed on the treatment planning system Isogray® according to Fein et al. (6) and Kong et al. (10). The nipple and the surgical scar are, respectively, delineated in yellow and purple. CLD, central lung distance; ICM, inferior central margin.

Mentions: Interfraction movements were daily assessed using an electronic PI device. The portal images of the medial tangential beam treating the whole mammary gland were acquired before each of the 25 first fractions. The central lung distance (CLD) and the inferior central margin (ICM) (Figure 1) were measured on the first acquired portal image by the medical physicist and compared with the digital reconstructed radiography (DRR) (6, 10). The CLD and ICM were defined to assess the interfraction variations along the anteroposterior and craniocaudal axes, respectively. The CLD and ICM were delineated on every daily portal image by the medical physicist. The measured data were then verified by both the medical physicist and the radiation oncologist. According to the methods reported in previously published articles, the measurements were performed on portal images (Figure 1), so that the lateral shifts could not be quantified (6, 7, 11, 12).


Dosimetric Effects of the Interfraction Variations during Whole Breast Radiotherapy: A Prospective Study.

Jacob J, Heymann S, Borget I, Dumas I, Riahi E, Maroun P, Ezra P, Roberti E, Rivera S, Deutsch E, Bourgier C - Front Oncol (2015)

Description of the inferior central margin and central lung distance on a digital reconstructed radiography performed on the treatment planning system Isogray® according to Fein et al. (6) and Kong et al. (10). The nipple and the surgical scar are, respectively, delineated in yellow and purple. CLD, central lung distance; ICM, inferior central margin.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4584980&req=5

Figure 1: Description of the inferior central margin and central lung distance on a digital reconstructed radiography performed on the treatment planning system Isogray® according to Fein et al. (6) and Kong et al. (10). The nipple and the surgical scar are, respectively, delineated in yellow and purple. CLD, central lung distance; ICM, inferior central margin.
Mentions: Interfraction movements were daily assessed using an electronic PI device. The portal images of the medial tangential beam treating the whole mammary gland were acquired before each of the 25 first fractions. The central lung distance (CLD) and the inferior central margin (ICM) (Figure 1) were measured on the first acquired portal image by the medical physicist and compared with the digital reconstructed radiography (DRR) (6, 10). The CLD and ICM were defined to assess the interfraction variations along the anteroposterior and craniocaudal axes, respectively. The CLD and ICM were delineated on every daily portal image by the medical physicist. The measured data were then verified by both the medical physicist and the radiation oncologist. According to the methods reported in previously published articles, the measurements were performed on portal images (Figure 1), so that the lateral shifts could not be quantified (6, 7, 11, 12).

Bottom Line: Daily movements were applied to the baseline treatment planning (TP1) to design a further TP (TP2).A total of 241 portal images were analyzed.The random and systematic errors were 2.6 and 3.7 mm for the CLD, 4.3 and 6.9 mm for the ICM, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Gustave Roussy , Villejuif , France.

ABSTRACT

Introduction: The aim of this work was to assess the dosimetric impact of the interfraction variations during breast radiotherapy.

Materials and methods: Daily portal imaging measurements were prospectively performed in 10 patients treated with adjuvant whole breast irradiation (50 Gy/25 fractions). Margins between the clinical target volume and the planning target volume (PTV) were 5 mm in the three dimensions. Parameters of interest were the central lung distance (CLD) and the inferior central margin (ICM). Daily movements were applied to the baseline treatment planning (TP1) to design a further TP (TP2). The PTV coverage and organ at risk exposure were measured on both TP1 and TP2, before being compared.

Results: A total of 241 portal images were analyzed. The random and systematic errors were 2.6 and 3.7 mm for the CLD, 4.3 and 6.9 mm for the ICM, respectively. No significant consequence on the PTV treatments was observed (mean variations: +0.1%, p = 0.56 and -1.8%, p = 0.08 for the breast and the tumor bed, respectively). The ipsilateral lung and heart exposure was not significantly modified.

Conclusion: In our series, the daily interfraction variations had no significant effect on the PTV coverage or healthy tissue exposure during breast radiotherapy.

No MeSH data available.


Related in: MedlinePlus