## 5 Conclusions  
The presented results prove that the different types of ultrasound probe that are widely available for standard handheld ultrasound evaluation can be successfully used as the imaging device in the multi-angle conventional ultrasound imaging method. However, limitations and possible artifacts that are different for the different probes depending on their shape, size, and beam-creation method must be taken into account during the design of the MACUI equipment. The geometry of the system, including the offset and angle of the probe, should be adjusted to the specific probe in order to fully exploit the imaging systems.  
Especially interesting is the fact that a relatively simple convex probe gives better 3D imaging results compared to the more advanced probes with beam-steering capabilities. So far, we have not encountered anywhere in the literature the use of a convex probe in the MACUI method. As the MACUI method aims to be a relatively non-expensive method of the 3D ultrasound breast imaging modality, the design of the device must take into account the modular approach that enables the adjustability of the system without cost-generating customization. This approach is possible with the use of a water tank that allows the breast to be scanned from below with universally attached conventional B-mode ultrasound probes. In order to adjust the size of the scanning area to the breast and position the ultrasound probe under the bottom of the tank as close to the nipple as possible, a sliding tank bottom can be constructed. This allows the examination of both very small (short when vertically immersed in water) and large (long) breasts. Additionally, to minimize the unwanted effects of ultrasound reflection inside the water tank, the internal surface should be designed with a proper ultrasound absorption policy.  
The biggest advantage of using the MACUI method is the possibility of applying any conventional B-mode ultrasound probe for 3D breast imaging, depending on the needs and capabilities. Moreover, it is possible to use any existing B-mode ultrasound scanner and all of the additional imaging capabilities that it offers (e.g., conventional CI, THI, ultrasound-coded transmission, SAFT, and others). We can also choose any of the available ultrasound frequencies. However, it should be noted that high frequencies increase imaging resolution but limit range due to increased ultrasound attenuation with frequency. In order to improve the quality of the MACUI images, we can also use image processing methods, i.e., a fuzzy preprocessor based on geometric formulations that can be easily implemented, even on hardware for any real-time applications [50].  
It is important, from a cost-wise point of view, that less advanced equipment may serve breast diagnostics very effectively.  
Conceptualization, M.S. and K.J.O.; investigation, M.S. and K.J.O.; methodology, M.S. and K.J.O.; software, M.S.; validation, M.S. and K.J.O.; resources, M.S. and K.J.O.; data curation, M.S.; writing--original draft preparation, M.S.; writing--review and editing, K.J.O.; visualization, M.S. and K.J.O.; supervision, K.J.O. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.