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Tumor Discovery                                                  An approach for classification of lung nodules



            CT imaging is less expensive and produces a variety of   using the point spread function. Deep et al.  presented
                                                                                                   [15]
            cross-sectional images of complete chest within a single   an algorithm for segmenting different nodule types such
            breath hold. For the analysis and early detection of lung   as juxtravascular, pleura tail, juxtapleural, solid, and non-
            nodules, it is now regarded as the best imaging technique.   solid nodules.
            Majority of the pulmonary nodules are benign; however,   Segmentation technique such as region growing and
            a small populace of them grow to be malignant. The   some hybrid fuzzy connectivity models was implemented.
            radiologists examine the CT scan to conclude whether a   Another segmentation scheme proposed by Dehmeshki
            nodule presents a chance for malignancy. The radiologist   et al.  used two different datasets taken from the LIDC
                                                                   [16]
            finds it challenging and time-consuming to detect some   database. Two different techniques such as dynamic
                                                        [6]
            nodules in the CT because of non-pathological features .   programming model and multidirection fusion techniques
            To get around this, radiologists opt for a computer-  are used to know the information, relationship between
            assisted approach as a backup method to validate their   adjacent  slices  and  to reduce segmentation  error.
            interpretation. Computer-based processes like computer-  Dehmeshki et al.  utilized a three-step procedure to find
                                                                            [17]
            aided detection (CAD) act as the radiologist’s “second pair   lung nodules. Initially, lung regions are segmented using
            of eyes” to analyze medical pictures for any problematic   an adaptive threshold algorithm. Second, lung vessel was
            regions. CAD is a topical technique designed to improve   removed using active contour model (ACM) and finally,
            the radiologists’ ability to find even the smallest lung   the suspicious nodules were located using a Hessian
            nodules at their earliest stages.                  matrix  (selected  shape  filter).  Delogu  et al.   developed
                                                                                                  [18]
              The main objective of CAD is to improve disease   a fully automated segmentation  method for  detecting
            identification by lowering the false negative (FN) rate   the pulmonary nodule. The authors used region growing
            brought on by observational omission. CAD was created   approach for a set of 130 CT images. Only 84 images
                                                                                                   [19]
            with the purpose of improving systematic clinical decision-  produced satisfactory result. Dheepak  et al.  proposed
            making  and  the  performance  of  detection  in  medical   a methodology for segmentation of juxtapleural lung
            imaging modalities. The aim of this paper is to focus on the   nodules.  The  authors  used  two  techniques  for  detecting
            architecture of different stages of CAD design with fruitful   the nodules from the lung. They are region growing and
                                                                                                   [20]
            results to assist the radiologists in detecting lung nodule at   shape curvature-based techniques. Doi et al.  developed
            early stage.                                       a method for segmenting the lung with the help of CT data.
                                                               The method was fully automatic and was composed of two
            2. Literature survey                               steps. They are robust active shape model (RASM) and
                                                               optimal surface finding method. Dolejsi et al.  proposed
                                                                                                   [21]
            In  the  field  of  lung  cancer  and  in  relation  to  the  work   a CAD to reduce the lung volume and juxtapleural nodule
            of this study, there are a number of existing models and   from thoracic CT images. For segmenting the lung
            algorithms. The stages of CAD systems can be used to   volume and nodule in juxtapleural, region growing and a
            categorize the existing work.                      3D-mass-spring mdel (MSM) was used. Elizabeth et al.
                                                                                                           [22]
              Various techniques, such as region growing [7,8] , watershed   proposed a region-based ACM based on local divergence
            segmentation , fuzzy logic, active contours, intensity-based   energies. This model was designed for blurred boundary
                      [9]
            thresholding, graph search algorithm , etc., were used for   and noisy images. The author used regularization function
                                         [10]
            region of interest (ROI) image segmentation Segmentation   to smoothen the boundary from different noise level.
            is an essential step in nodule detection. The survey in   The system performance was evaluated with Chan-Vese’s
            various existing segmentation techniques for lung nodule   (CV) model, region scalable fitting and local Gaussian
                                                                                    [23]
            is discussed in detail. Dai et al.  developed a segmentation   fitting. Enquobahrie et al.  developed an edge detection
                                    [11]
            algorithm known as segmentation by registration. The   model, which precisely diffuses the edge space. Farag
                                                                   [24]
            authors compared their work with algorithms such as   et al.  proposed a newly developed nodule segmentation
            automatic region growing, interactive region growing and   algorithm which was stable, accurate, and automated. Farag
                                                                   [25]
            voxel classification. Daneshmand et al.  demonstrated a   et al.  developed a segmentation model to segment the
                                           [12]
            precise technique designed for toning lung nodules in chest   juxtavascular and ground glass (GG) nodules. The authors
            CT scans. The region growing, optimal thresholding and   proposed parametric mixture model for juxtavascular
            optimal cube registration were used in this system Dawoud   nodules and ACM for detecting leakage boundary.
            et al.  proposed an adaptive border marching which is a   A nonlinear level set method proposed by Farag
                [13]
            geometric-based algorithm used for segmenting the lung.   et al.  used adaptive velocity function and edge stopping
                                                                   [26]
            De Nunzio et al.  performed phantom experiment for CT   function to employ a noise-free segmentation model.
                         [14]
            image. The density of the nodule and its size was measured   Gambhir et al.  focused on segmenting the lung nodule
                                                                           [27]
            Volume 2 Issue 1 (2023)                         2                           https://doi.org/10.36922/td.317
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