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Evaluation of the Flash effect in breast irradiation using TomoDirect: an investigational study.

Kang DG, Park SI, Kim SH, Chung MJ, Lee KM, Lee JH - J. Radiat. Res. (2015)

Bottom Line: The Flash effect in the air was compared with each set-up error of 5, 10 and 15 mm, respectively.Without Flash, when 5-, 10- and 15-mm set-up errors applied in the PTV, relative doses of 87.88, 23.73 and 7.94% were observed, respectively.However, in Flash 3, which was equal to the usual air margin of 1.875 cm, a relative dose of 104.24% ± 0.30% was observed, irrespective of set-up errors (5 mm to 15 mm).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, St Vincent's Hospital, the Catholic University of Korea, 93, Ji-dong, Paldal-gu, Suwon, Gyeonggi-do, Korea Department of Biomedical Engineering, Electronic Engineering, Jeju National University of Korea, Jeju-si, Jeju Special Self-Governing Province, Korea.

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The plan image in tangential area according to the presence or existence of Flash. (A) Flash not applied, (B) Flash 1 applied, (C) Flash 2 applied and (D) Flash 3 applied.
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RRU118F4: The plan image in tangential area according to the presence or existence of Flash. (A) Flash not applied, (B) Flash 1 applied, (C) Flash 2 applied and (D) Flash 3 applied.

Mentions: The DVH showed notable gap-related differences between the body and the PTV contour (Fig. 3). The minimum, maximum and average doses for PTV-x are shown in Table 1. The dose parameter of the PTV in places where the body contour and the PTV contour concurred showed the worst dose distribution, with a maximum dose (Dmax) of 21.29 Gy, a minimum dose (Dmin) of 9.42 Gy, and an average dose (Davg) of 19.05 Gy. For PTV-x, Dmax showed constant values of 20.85 ± 0.034 Gy from PTV-1 to PTV-5. Dmin from PTV-1 to PTV-3 increased from 13.88 Gy to 15.10 Gy and then to 15.86 Gy, but it was still smaller than the prescription dose of 18 Gy. In contrast, Dmin in PTV-4 and PTV-5 was 17.80 Gy in 98.88% of the prescription doses. Similar to Dmax, Davg showed a constant dose distribution of 18.81 ± 0.03 Gy for all PTV-x. The PTV-4 contour, which has a constant dose distribution below PTV-4, is currently used in the evaluation of the Flash effect in the tangential region and is associated with breast irradiation using TomoDirect. When there was no Flash on PTV-4, the dose at point x was 18.92 Gy (Fig. 4a). When Flash was present, the dose at point x was 19.87 ± 0.035 Gy, a 5% increase regardless of the number of Flash x (Fig. 4b, c and d).Table 1.


Evaluation of the Flash effect in breast irradiation using TomoDirect: an investigational study.

Kang DG, Park SI, Kim SH, Chung MJ, Lee KM, Lee JH - J. Radiat. Res. (2015)

The plan image in tangential area according to the presence or existence of Flash. (A) Flash not applied, (B) Flash 1 applied, (C) Flash 2 applied and (D) Flash 3 applied.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380062&req=5

RRU118F4: The plan image in tangential area according to the presence or existence of Flash. (A) Flash not applied, (B) Flash 1 applied, (C) Flash 2 applied and (D) Flash 3 applied.
Mentions: The DVH showed notable gap-related differences between the body and the PTV contour (Fig. 3). The minimum, maximum and average doses for PTV-x are shown in Table 1. The dose parameter of the PTV in places where the body contour and the PTV contour concurred showed the worst dose distribution, with a maximum dose (Dmax) of 21.29 Gy, a minimum dose (Dmin) of 9.42 Gy, and an average dose (Davg) of 19.05 Gy. For PTV-x, Dmax showed constant values of 20.85 ± 0.034 Gy from PTV-1 to PTV-5. Dmin from PTV-1 to PTV-3 increased from 13.88 Gy to 15.10 Gy and then to 15.86 Gy, but it was still smaller than the prescription dose of 18 Gy. In contrast, Dmin in PTV-4 and PTV-5 was 17.80 Gy in 98.88% of the prescription doses. Similar to Dmax, Davg showed a constant dose distribution of 18.81 ± 0.03 Gy for all PTV-x. The PTV-4 contour, which has a constant dose distribution below PTV-4, is currently used in the evaluation of the Flash effect in the tangential region and is associated with breast irradiation using TomoDirect. When there was no Flash on PTV-4, the dose at point x was 18.92 Gy (Fig. 4a). When Flash was present, the dose at point x was 19.87 ± 0.035 Gy, a 5% increase regardless of the number of Flash x (Fig. 4b, c and d).Table 1.

Bottom Line: The Flash effect in the air was compared with each set-up error of 5, 10 and 15 mm, respectively.Without Flash, when 5-, 10- and 15-mm set-up errors applied in the PTV, relative doses of 87.88, 23.73 and 7.94% were observed, respectively.However, in Flash 3, which was equal to the usual air margin of 1.875 cm, a relative dose of 104.24% ± 0.30% was observed, irrespective of set-up errors (5 mm to 15 mm).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, St Vincent's Hospital, the Catholic University of Korea, 93, Ji-dong, Paldal-gu, Suwon, Gyeonggi-do, Korea Department of Biomedical Engineering, Electronic Engineering, Jeju National University of Korea, Jeju-si, Jeju Special Self-Governing Province, Korea.

Show MeSH
Related in: MedlinePlus