Related Experiment Video
Updated: Jun 25, 2025
Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Quantify the Effect of Air Gap Errors on Skin Dose for Breast Cancer Radiotherapy
Chunbo Tang1,2, Jun Yuan1,2, Hailiang Guo1,2
1Department of Radiation Oncology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China.
Air gap errors in breast cancer radiotherapy significantly increase skin dose, impacting treatment outcomes. Larger air gaps correlate with higher mean skin dose, tumor control probability, and normal tissue complication probability.
Area of Science:
- Radiation Oncology
- Medical Physics
- Radiotherapy Planning
Background:
- Postoperative breast cancer radiotherapy often uses intensity-modulated radiation therapy (IMRT).
- Accurate dose delivery to the skin is crucial, especially in areas with potential air gaps like the inframammary fold.
- Air gap errors can lead to underdosage or overdosage, affecting treatment efficacy and toxicity.
Purpose of the Study:
- To quantify the impact of simulated air gap errors on the skin dose in patients undergoing postoperative breast cancer radiotherapy.
- To evaluate the relationship between air gap characteristics (volume, depth) and radiation dose metrics.
- To assess the influence of these errors on tumor control probability (TCP) and normal tissue complication probability (NTCP).
Main Methods:
- Retrospective analysis of 55 patients treated with tangential IMRT after modified radical mastectomy.
- Simulation of air gap depth errors (2mm, 3mm, 5mm) at skin depressions or inframammary folds.
- Calculation of mean skin dose (Dmean), TCP, and NTCP using a multivariable generalized estimating equation (GEE) model.
- Analysis of the correlation between Dmean and air gap volume, as well as the lateral beam's average angle (AALB).
Main Results:
- Simulated air gaps of 2mm, 3mm, and 5mm increased the mean skin dose by 0.46 Gy, 0.51 Gy, and 0.59 Gy, respectively (p < .001).
- Tumor control probability (TCP) showed a similar increasing trend with air gap depth.
- Normal tissue complication probability (NTCP) values also gradually increased as air gap depth increased.
- Multivariable GEE analysis identified air gap volume and AALB as significant predictors of Dmean.
Conclusions:
- Even small air gap errors in radiotherapy can elevate skin dose, TCP, and NTCP.
- The volume of air gaps and the lateral beam's average angle are key factors influencing local skin dose.
- A multivariable GEE model effectively quantifies the impact of air gap errors on radiotherapy outcomes.
More Related Videos
06:20Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition
Published on: March 11, 2021
07:31Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
Published on: May 9, 2014
