Related Experiment Video
Updated: Feb 15, 2026

Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Radiotherapy setup displacements in breast cancer patients: 3D surface imaging experience
Ana Cravo Sá1, Ana Fermento1, Dalila Neves1
1Área Científica de Radioterapia, Escola Superior de Tecnologia da Saúde de Lisboa - Instituto Politécnico de Lisboa, Avenida D. João II, lote 4.69.01, 1990-096 Lisboa, Portugal.
Aim:
In this study, we intend to compare two different setup procedures for female breast cancer patients.
Background:
Imaging in radiotherapy provides a precise localization of the tumour, increasing the accuracy of the treatment delivery in breast cancer.
Materials And Methods:
Twenty breast cancer patients who underwent whole breast radiotherapy (WBRT) were selected for this study. Patients were divided into two groups of ten. Group one (G1) was positioned by tattoos and then the patient positioning was adjusted with the aid of AlignRT (Vision RT, London, UK). In group two (G2), patients were positioned only by tattoos. For both groups, the first 15 fractions were analyzed, a daily kilovoltage (kV) cone beam computed tomography (CBCT) image was made and then the rotational and translational displacements and, posteriorly, the systematic (Σ) and random (σ) errors were analyzed.
Results:
The comparison of CBCT displacements for the two groups showed a statistically significant difference in the translational left-right (LR) direction (ρ = 0.03), considering that the procedure with AlignRT system has smaller lateral displacements. The results of systematic (Σ) and random (σ) errors showed that for translational displacements the group positioned only by tattoos (G2) demonstrated higher values of errors when compared with the group positioned with the aid of AlignRT (G1).
Conclusions:
AlignRT could help the positioning of breast cancer patients; however, it should be used with another imaging method.
Related Concept Videos
Displacement Current
Position and Displacement
Position and Displacement Vectors
Further, several important kinds of...
Significance of Displacement Current
Angular Velocity and Displacement
EDTA: Direct, Back-, and Displacement Titration
Direct titration involves buffering the metal ion solution to the desired pH and directly titrating with standard EDTA until the endpoint. The optimum pH ensures a large conditional formation constant of metal−EDTA and visibility of the free indicator color in the solution. In addition, auxiliary complexing reagents are used to prevent the precipitation of metal hydroxides...

