this 34-year - old male patient had an impacted mytilus coruscus shell in the esophagus . , the patients received a chest ct after contrast enhancement using a toshiba aquillion operating at 120 kvp and 62 mas , with a slice thickness of 3 mm ( fig . 1 ) . this 52-year - old male patient had a fish bone lodged in the espophagus . prior to fb removal , the patient received a chest ct after contrast enhancement using a siemens navigator operating at 120 kvp and 90 mas , with a slice thickness of 2 mm ( fig . the axial ct data were saved in dicom file format . to reconstruct the 3d images , the outer surfaces of the fb , skin , bones including vertebrae , inner surface of the trachea , and esophagus were drawn in all frames after detection of the outlines . the 3d images and photographs were compared with respect to the shape and location of each fb in the esophagus . after rotation of the 3d images , they looked similar in shape and orientation to the photographs of the fbs that had been removed . this 34-year - old male patient had an impacted mytilus coruscus shell in the esophagus . , the patients received a chest ct after contrast enhancement using a toshiba aquillion operating at 120 kvp and 62 mas , with a slice thickness of 3 mm ( fig . the fish bone was removed by open thoracotomy under general anesthesia . prior to fb removal , the patient received a chest ct after contrast enhancement using a siemens navigator operating at 120 kvp and 90 mas , with a slice thickness of 2 mm ( fig . the axial ct data were saved in dicom file format . to reconstruct the 3d images , the outer surfaces of the fb , skin , bones including vertebrae , inner surface of the trachea , and esophagus were drawn in all frames after detection of the outlines . the 3d images and photographs were compared with respect to the shape and location of each fb in the esophagus . after rotation of the 3d images , they looked similar in shape and orientation to the photographs of the fbs that had been removed . although the flexible fiberoptic endoscope is a very popular tool for fb extraction , the rigid esophagoscope is equally safe and represents a good tool in the hands of an experienced surgeon . if endoscopy fails , an open thoracotomy is the method of last resort . in asian countries , since fish bones and shells tend to be calcium - rich , they are visible upon routine x - ray examination , if sufficiently large in size . use of a flexible fiberoptic endoscope can often allow both a definitive diagnosis and extraction of the fb . in the present cases , prompt extraction of the rigid and sharp - edged fbs is necessary , since they can cause erosion and laceration of the esophageal mucosa if left untreated . endoscopic extraction is not risk - free , and problems that arise can demand emergency surgery . rapid knowledge of an esophageal fb , specifically , its composition ( i.e. , hard or soft ) , shape , size , location , and orientation , is vital for a surgeon in tailoring the safest and most effective treatment . our patients were successfully treated under endoscopy or by thoracotomy with full knowledge about the fb . at the time of the treatment the 3d reconstructions were made retrospectively , as was the comparison of these image reconstructions with actual photographs . the time required for making the reconstructed image was less than 30 minutes once the chest ct had been acquired , it took even less time when skilled personnel was involved . this shows another example of the practical value of ct reconstruction from the clinical point of view . therefore , while the present data was not instrumental in the treatment of the patients from which the data was drawn , the potential of ct reconstruction for future cases was confirmed . in the case of the shell fb , photographs of the shell that was removed were taken without inclusion of a ruler and the images were distorted due to endoscope angles , so measurements were not possible . for this fb , the 3d reconstructed images were helpful in determining the shape , size , and the relative location of the shell , and its orientation in the esophagus . rotation of the 3d images could be performed to mimic the endoscopic images and to be used in simulation of surgical procedures if needed . as a result , the patient was required to fast for 7 days until a second endoscopy confirmed healing . in this patient , real photographs and 3d images were available and were used for comparisons of fb size , location ( in the 3d image only ) , and orientation . the shape in the 3d images was very similar to that in the real fb photograph . the 3d image was rotated to match the endoscopic view of the fb ; the accuracy of the result indicates the potential of the approach as a simulation method . information concerning the distance from a target point to the fb is available with one mouse click . since ct is calibrated data , the 3d images can always be used for measuring distance . a 3d reconstructed image from ct data can be converted into a real touchable physical model through rapid prototype ( rp ) technology . before operations for cardiac anomaly or bone - destroying cancer surgery , the use of rp can generate a surgical simulation or allow a bone defect to be measured to make implants or flaps . patients with a vessel anomaly , vascular tumor , or stabbing injury can also benefit from the 3d reconstruction technique . organs with hollow spaces occupied by fluid or air are the best candidates for virtual endoscopy . the technique has been adapted in the screening for polyps or other space - occupying lesions of the large intestine . virtual endoscopy has not been attempted frequently for esophagus procedures , since flexible fiberoptic endoscopy is quick and convenient . in contrast , virtual esophagoscopy requires pretreatment with a gas - forming formula and motility - decreasing injections that distend the esophageal lumen to allow full examination of the esophagus . the gas - forming medicine might not be suitable for patients with an esophageal fb because of the danger of leakage of the medicine through damaged esophageal mucosa . until now , virtual endoscopy has not been tried in patients with esophageal fb . the reconstructions were able to accurately indicate the shape , size , location , and orientation of the fb in the esophagus in two patients . the type of material comprising an fb can not be determined in the absence of information concerning the ingested material . on the other hand , endoscopy is superior to 3d reconstruction in identifying the composition of an fb . the information in a 3d reconstructed image can be quickly converted into an rp , which can be used to simulate an extraction procedure such as flexible fiberoptic endoscopy or open surgery . finally , the present ct data was acquired in 2- or 3-mm - thick slices . use of slices of 1 mm thickness or less would provide finer detail , and the resulting 3d reconstruction would even more realistically mimic the fb .