# A Novel Breast-Volume Self-Measurement Method with Improved Convenient and Accuracy
## 2 Methodology
### Breast-Volume Measurement Validation  
To ensure objectivity and authoritative results, the breast specimen drainage method was adopted as the gold standard [32]. Two groups were defined in this study: the reference group, in which breast volumes were measured using the gold standard, and the comparison group, which included breast-volume measurements obtained through different methods (the proposed self-measurement method, existing breast-volume formulas, and 3D scanning techniques). By analyzing the error between each method in the comparison group and the gold standard, we systematically evaluated the accuracy of the new method.  
As shown in Figure 4, the experimental materials included both single and bilateral medical breast models, all at a 1:1 scale. To ensure consistency and comparability, bilateral breast models with identical parameters were used as test samples in other control experiments. The medical breast model parameters include the following: upper-cup arc length of 12.0 cm, lower-cup arc length of 7.5 cm, front-cup arc length of 9.0 cm, side-cup arc length of 8.5 cm, and breast height of 5.5 cm.  
The breast specimen drainage method, based on the principle of buoyancy, accurately determines breast volume by measuring the volume of displaced liquid. This method is commonly used to validate the accuracy of other breast-volume measurement techniques.  
In the existing breast-volume formula methods, mechanical tools such as tape measures and Martin calipers are typically used to measure the linear or curved distances between various parts of the breast. These measured values are then applied to fitting formulas to calculate breast volume, a process known as the linear calculation method. The most common formula was proposed by [PERSON] et al. [33], as shown in the Equation below:  
\[V=\pi/3\times MP2\ (MR+LR+IR).\]  
In the formula, \(MP\), \(MR\), \(LR\), and \(IR\) represent diameters obtained from surface measurements of the breast, corresponding to breast height, anterior arc length, lateral arc length, and inferior arc length, respectively.  
For the 3D scanning method, this study employed the ATOS Q 12M 3D scanner (GOM, Braunschweig, Germany) to scan the medical breast model, as shown in Figure 5. The device uses triangulation and structured light projection to capture the 3D coordinates of the object. Since the scanned breast model cannot directly provide volume measurements,  
Figure 4: Experimental materials.  
the final volume was automatically calculated using the GOM Inspect Professional module within the GOM Suite 2022 software.  
The steps for comparing and validating breast-volume measurements are as follows: (1) Place the simulated breast model in a container filled with water, record the breast volume measured by the specimen drainage method, and use it as reference data. (2) Apply the linear breast-volume calculation method, compute the breast volume based on the model's parameters, and record the results. (3) Use 3D scanning equipment to scan the breast model, acquire the 3D data, and calculate the volume. (4) Utilize the new breast-volume measurement method proposed in this study, measure the model's volume, and record the results.