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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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Plan image with Flash 0, 1, 2 and 3, each applied to show the dimension of Flash. (A) Air interface transverse image with Flash applied to PTV-4. Point x refers to the point of interest in the tangential area. (B) PTV rectangle transverse image inside the phantom. The pink contour is the normal PTV and the blue contour is the expanded PTV. Anterior (a, b, c), interior (a, b, c, d) and posterior (a, b, c) are points of comparison.
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RRU118F2: Plan image with Flash 0, 1, 2 and 3, each applied to show the dimension of Flash. (A) Air interface transverse image with Flash applied to PTV-4. Point x refers to the point of interest in the tangential area. (B) PTV rectangle transverse image inside the phantom. The pink contour is the normal PTV and the blue contour is the expanded PTV. Anterior (a, b, c), interior (a, b, c, d) and posterior (a, b, c) are points of comparison.

Mentions: Flash ±x is defined by opening x number of the leaves. Flash 1 is defined as opening an extra outer leaf with a width of 0.625 cm in a distance from the source axis of 85 cm. Thus, opening five leaves indicates that an extra leaf opening is available to 3.125 cm. To investigate the characteristics of the plan according to the presence of Flash in the phantom, dose distribution parameters of plans were compared using beam angles of 90° and 270°. In order to allow for set-up error and respiration, a margin width of 1.5 to 2 cm was extended from the PTV of the glandular breast tissue when a breast was irradiated [10]. Thus, an investigational plan was designed using Flash 3 that equalled the usual air margin of 1.875 cm, and other plans without Flash were compared for point x of the tangential region (Fig. 2a).Fig. 2.


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)

Plan image with Flash 0, 1, 2 and 3, each applied to show the dimension of Flash. (A) Air interface transverse image with Flash applied to PTV-4. Point x refers to the point of interest in the tangential area. (B) PTV rectangle transverse image inside the phantom. The pink contour is the normal PTV and the blue contour is the expanded PTV. Anterior (a, b, c), interior (a, b, c, d) and posterior (a, b, c) are points of comparison.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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

RRU118F2: Plan image with Flash 0, 1, 2 and 3, each applied to show the dimension of Flash. (A) Air interface transverse image with Flash applied to PTV-4. Point x refers to the point of interest in the tangential area. (B) PTV rectangle transverse image inside the phantom. The pink contour is the normal PTV and the blue contour is the expanded PTV. Anterior (a, b, c), interior (a, b, c, d) and posterior (a, b, c) are points of comparison.
Mentions: Flash ±x is defined by opening x number of the leaves. Flash 1 is defined as opening an extra outer leaf with a width of 0.625 cm in a distance from the source axis of 85 cm. Thus, opening five leaves indicates that an extra leaf opening is available to 3.125 cm. To investigate the characteristics of the plan according to the presence of Flash in the phantom, dose distribution parameters of plans were compared using beam angles of 90° and 270°. In order to allow for set-up error and respiration, a margin width of 1.5 to 2 cm was extended from the PTV of the glandular breast tissue when a breast was irradiated [10]. Thus, an investigational plan was designed using Flash 3 that equalled the usual air margin of 1.875 cm, and other plans without Flash were compared for point x of the tangential region (Fig. 2a).Fig. 2.

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