Related Experiment Video
Updated: Feb 9, 2026

Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Breast Cancer Adjuvant Radiotherapy Without Tattoos: Comparison Between Surface Imaging and Four-point Localisation
C Lenci1, F De Felice1, M Tomaciello1
1Radiation Oncology, AOU Policlinico Umberto I, Department of Radiological, Oncological and Pathological Sciences, "Sapienza" University of Rome, Rome, Italy.
Aims:
Precise patient positioning is critical for successful radiotherapy (RT) in right-sided breast cancer, ensuring adequate tumour coverage while sparing organs at risk (OARs). Conventional tattoo-based setups can cause patient distress. Surface-guided radiotherapy (SGRT) using systems like AlignRT offers a promising, noninvasive alternative. This prospective single-centre study compared the accuracy and reproducibility of SGRT versus conventional tattoo-based positioning for right-sided breast cancer RT.
Materials And Methods:
Eligible patients underwent a crossover study design, receiving both positioning methods at different points in their treatment. Setup errors were quantified from pretreatment cone-beam computed tomography (CT) registrations. Observations were analysed for each group. Data were analysed using the Shapiro-Wilk test for normality and independent two-sample t-tests to compare positioning errors.
Results:
A total of 52 patients were enrolled, and a total of 136 observations were analysed for each group. SGRT positioning resulted in significantly lower mean errors compared to the tattoo-based method across all three directions: longitudinal (P < 0.001), vertical (P < 0.001) and lateral (P = 0.044). Box plot analysis confirmed SGRT had less inter-fraction variability and fewer clinically significant outliers (errors >1 cm), demonstrating superior setup stability.
Conclusions:
SGRT with AlignRT provides superior accuracy and reproducibility for patient positioning in right-sided breast cancer RT. This approach enhances treatment precision, reduces setup variability, and improves patient experience by eliminating the need for permanent tattoos. Future studies are warranted to confirm these findings and assess long-term clinical outcomes.
Related Concept Videos
The Sense of Self: Reflected Self-Appraisal and Social Comparison
Multiple Comparison Tests
It would be easy to compare two samples using a significance alpha level of 0.05. In other words, there is only one sample pair to be compared. However, it would be difficult to identify a significantly different sample if the number...
Evolutionary Relationships through Genome Comparisons
Comparison Between Electrical And Gravitational Forces
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
Comparison between RL and RC circuits
Surface Tension and Surface Energy
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...

