Our study aimed to correlate the overall 3-dimensional (3-D) shape of the breast to the compensation depth to produce a homogeneous dose distribution using the electronic tissue compensation (ECOMP) treatment technique. The study involved creating a number of semioval water phantoms with the diameter of the larger axis representing the breast separation and the shorter axis representing the distance from the chest wall to the apex of the breast. Multiple plans with 2 tangential fields were created for each phantom using different transmission penetration depths (TPDs) to determine the optimum TPD value based on the evaluation of dose uniformity and maximum hot spot. Optimum TPD values from the semioval water phantom plans were plotted on a graph as a function of separation and radius and were used as guidelines to choose the optimum TPD for the breast patient's cases. A total of 10 patients who had been treated with radiation therapy using ECOMP tangential fields were randomly selected. The separation and the radius of the breast were measured for 3 regions (superior, middle, and inferior) to retrospectively determine the optimum TPD from the graph for each region. These TPD values were then used to plan the breast cases. For all the patients studied, the optimized TPD technique produced a lower average homogeneity index (HI) value of 0.658 than the standard ECOMP technique of 0.856. These results showed that optimized TPD technique produced a more homogeneous dose distribution than the standard ECOMP technique. By measuring the breast size based on breast separation and the chest wall-to-apex distance at different locations along the superior-inferior axis of the breast, the optimum TPD can be determined at each location to provide a homogeneous dose distribution. A module can be created within the planning system to automatically assign the optimum TPD for both tangential fields so uniform fluence maps can be achieved throughout the whole breast volume. This method can serve as a guideline in ECOMP during the treatment planning to obtain a homogeneous dose distribution.
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- Dosimetric improvements following 3D planning of tangential breast irradiation.Int. J. Radiat. Oncol. Biol. Phys. 2000; 48: 1569-1574
- Evaluation of compensation in breast radiotherapy: A planning study using multiple static fields.Int. J. Radiat. Oncol. Biol. Phys. 2000; 46: 671-679
- Intensity modulation to improve dose uniformity with tangential breast radiotherapy: Initial clinical experience.Int. J. Radiat. Oncol. Biol. Phys. 2000; 48: 1559-1568
- Factors influencing cosmetic results after conservation therapy for breast cancer.Int. J. Radiat. Oncol. Biol. Phys. 1995; 31: 753-764
- Optimizing breast cancer treatment efficacy with intensity-modulated radiotherapy.Int. J. Radiat. Oncol. Biol. Phys. 2002; 54: 1336-1344
- Large breast size as a risk factor for late adverse effects of breast radiotherapy: Is residual dose inhomogeneity, despite 3D treatment planning and delivery, the main explanation?.Radiother. Oncol. 2011; 100: 236-240
- The influence of breast size on late radiation effects and association with radiotherapy dose inhomogeneity.Radiother. Oncol. 1994; 33: 106-112
- Improvement of dose distribution with irregular surface compensator in whole breast radiotherapy.J. Med. Phys. 2013; 38: 115-119
- Dosimetric parameter comparison of the electronic tissue compensator technique with the conventional physical wedge technique for the whole breast treatment.Med. Phys. 2008; 35: 2837
- A dosimetric comparison of electronic compensation, conventional intensity modulated radiotherapy and tomotherapy in patients with early-stage carcinoma of the left breast.Int. J. Radiat. Oncol. Biol. Phys. 2007; 68: 1505-1511
- Irregular surface compensation for radiotherapy of the breast: Correlating depth of the compensation surface with breast size and resultant dose distribution.Br. J. Radiol. 2010; 83: 159-165
Published online: March 07, 2018
Accepted: January 16, 2018
Received in revised form: December 31, 2017
Received: June 28, 2017
Published by Elsevier Inc. on behalf of American Association of Medical Dosimetrists.