## 4 Discussion
Some papers used human anatomy for the evaluation parameters, such as the vertebrae in thoracic, spinal, and pelvic regions, and rasterstereographic measurements, which present the abnormality of the spine clearly, but these metrics are quite complex and tedious for diagnosis for study [20; 23; 24; 25]. Since it is necessary to obtain and evaluate the specific characteristics of abnormal measurements and values that manifest on the spine, which are outlined in Table 3, the parameters outlined in study [24] must be assessed in each thoracic, spinal, and pelvis region, whilestudy [25] examined 40 VRS features. Consequently, it is imperative to ensure utmost precision in order to capture comprehensive measurement particulars and mitigate the risk of misdiagnosis. However, GRF and EMG have proven to be effective metrics, but the ability of the metric to detect scoliosis in real-world scenarios is limited since the instrument used for analysis can only be used through experiments in the laboratory. Apparently, three studies use the common imaging modality of X-ray, and two studies use MRI or CT scans to acquire spine images. MRI or CT scans set out higher quality images than X-ray, but still, radioactivity from CT scans should be considered since X-ray has low radioactivity, which is safer and cheaper. MRI is advantageous in terms of radiation exposure due to its utilization of a magnetic field during the scanning process, which proves to be safer when compared to plane radiographs and CT scans. However, it is most commonly employed for patients exhibiting presumed atypical characteristics of idiopathic scoliosis or those in the juvenile phase, where radiation is not a viable option for conducting scanning [5; 36]. Both CT scans and MRI scans contribute to high precision in image quality and enhance medical diagnosis. Unfortunately, these scans are accompanied by a hefty price tag and are limited to patients with congenital and severe curvatures, and they are commonly utilized subsequent to the diagnosis of patients using X-ray scanning. Clinicians commonly use X-ray imaging for scoliosis detection, and it is particularly suitable for first-time diagnosis or detection of scoliosis in its early stages. Several studies [37; 38] have proven that X-ray can be a good modality accompanied by advanced algorithm mechanisms in scoliosis diagnosis. Another 11 studies implemented new and atypical modalities in obtaining the spine image that need to consider the cost-effectiveness and image quality obtained when using the modalities. The image quality used is very important, as it can affect the outcome of diagnosis, and thus modalities that can yield high-quality images are the best; however, other factors, such as radioactivity and cost, need to be considered for the assessment. Therefore, the choices of imaging modality depend on the needs and requirements during the diagnosis. From the assessment methods of scoliosis diagnosis in Table 3, researchers have come up with different diagnostic methods that have certain limitations. As we can see, it is found that some studies implemented back surface topography techniques in the diagnosis to obtain the measurements, as they can reduce the exposure of radioactivity to humans. Methods in this review that implement this concept are rastersteography, photogrammetry, 3D reconstructions of the spine and rib cage, 3D structure analysis of the human torso, and a triangulation system that integrates back surface analysis and landmark localization. However according to study [39], the author said that back surface topography techniques need to be performed with great precision due to the uneven and variable nature of human back anatomy. The parameters use in these notions for scoliosis measurement require more elaboration and details of human geometry, as we can see in the studies [20; 22; 23; 24; 25; 31; 34], and this must be followed with an advanced mathematical algorithm or image processing for the analysis.