We hypothesize that for large pendulous breasts, breast irradiation in supine and prone position are equivalent with regard to coverage of the PTV, but with a better dose homogeneity in prone position and a smaller radiation exposure of lung and heart.The purpose of this study is to compare the 3-D dose distribution in PTV(Planning Target Volume) and normal tissues in prone position versus supine position.
Local excision followed by adjuvant radiotherapy has become standard treatment for women with early-stage breast cancer. Adjuvant radiotherapy may encounter technical difficulties in patients with pendulous breasts when treated in supine position. Based upon literature and our own preliminary experiences, we hypothesize that for large pendulous breasts, breast irradiation in supine and prone position are equivalent with regard to coverage of the PTV, but with a better dose homogeneity in prone position and a smaller radiation exposure of lung and heart. However, no quantitative data are yet available to test this hypothesis. Therefore, the aim of our study is to compare the 3-D dose distribution in PTV and normal tissues in prone position versus supine position. For treatment in prone-position an in-house developed device, the "mammaboard" was used.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
10
use of mamma board during radiotherapy
Maastricht Radiation Oncology
Heerlen, Limburg, Netherlands
Dose Homogeneity 1: PTV
Quantitatively compare the 3 D dose distribution in the PTV (Planning Target Volume) and normal tissues in prone position versus supine position
Time frame: 1 day after treatment planning
Dose Homogeneity 2: V105% and V107%
Quantitatively compare the 3 D dose distribution in the PTV (Planning Target Volume) in prone position versus supine position
Time frame: 1 day after treatment planning
Dose Homogeneity 3: V95 %
PTV coverage (% of PTV \< 95% of prescribed dose) in prone position versus supine position
Time frame: 1 day after treatment planning
PTV Coverage in Organs at Risk: MLD (Gy)
Doses in organs at risk: lung MLD (Mean Lung Dose)
Time frame: during treatment planning
PTV Coverage in Organs at Risk: Heart V30
Doses in organs at risk: heart V30: the volumes (%) of the heart that received \>= 30Gy
Time frame: during treatment planning
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