Dersleri yüzünden oldukça stresli bir ruh haline sikiş hikayeleri bürünüp özel matematik dersinden önce rahatlayabilmek için amatör pornolar kendisini yatak odasına kapatan genç adam telefonundan porno resimleri açtığı porno filmini keyifle seyir ederek yatağını mobil porno okşar ruh dinlendirici olduğunu iddia ettikleri özel sex resim bir masaj salonunda çalışan genç masör hem sağlık hem de huzur sikiş için gelip masaj yaptıracak olan kadını gördüğünde porn nutku tutulur tüm gün boyu seksi lezbiyenleri sikiş dikizleyerek onları en savunmasız anlarında fotoğraflayan azılı erkek lavaboya geçerek fotoğraflara bakıp koca yarağını keyifle okşamaya başlar

GET THE APP

Novel Anisotropic Margin Calculation Based On the Cumulative Frequency Distribution of Uncertainties in the Clinical Target Volume | OMICS International
ISSN:2167-7964

# Novel Anisotropic Margin Calculation Based On the Cumulative Frequency Distribution of Uncertainties in the Clinical Target Volume

Visit for more related articles at OMICS Journal of Radiology

#### Abstract

Objective: The purpose of this study was to determine the PTV margins from the cumulative frequency of uncertainties of the clinical target volume (CTV) position obtained using hybrid-image guided radiotherapy (H-IGRT) with volumetric-modulated arc therapy (VMAT).

Materials and Methods: Study participants were 22 patients with intermediate-risk prostate cancer who underwent VMAT. All patients were treated using the following image-guided (IG) procedure: 1) no-correction skin mark setup (no- IG); 2) bony anatomy registration with 2D-imaging (2D-IG); and 3) organ registration using CBCT images (3D-IG). The systematic (Σtot) and random (σtot) errors were obtained from the no-IG, 2D-IG, and 3D-IG registration images of 198 fractions. The PTV margin was computed using the cumulative frequency distribution of the actual position errors of the CTV, and which was compared with the formulation by MPTV = 2.5 Σtot + 0.7 σtot.

Results: The margin size of 3D IG procedure was as follows: 3D-IG: 7.6, 5.4, and 3.5 mm for the AP, SI, and LR axes, respectively. Using MPTV = 2.5 Σtot + 0.7 σtot: 3D-IG: 4.2, 3.7, and 1.3 mm for the AP, SI, and LR axes, respectively. In MPTV: = α Σtot + β σtot, the coefficients α and β were α = 3.4, 2.3, and 4.6 and β = 2.9, 3.0, and 3.0 for AP, SI, and LR, respectively.

Conclusion: The margin size (MPTV) calculated by our modified formulation based on the margin direction satisfied 99% of the prescription dose coverage in each direction and a minimum of 95% of the dose coverage to the CTV for all patients using H-IGRT

--

#### Tables and Figures at a glance

 Table 1 Table 2 Table 3 Table 4

 Table 5 Table 6 Table 7

#### Figures at a glance

 Figure 1 Figure 2 Figure 3

### Article Usage

• Total views: 14292
• [From(publication date):
August-2015 - Apr 17, 2024]
• Breakdown by view type
• HTML page views : 9829