We investigated the transmission characteristics of formalin fixed human liver samples in which normal liver tissue and malignant liver tumor were mixed using terahertz (THz) coherent synchrotron radiation at an infrared free-electron laser (FEL) facility at Nihon University. Infrared-FEL imaging has indicated that the amount of water molecules in the tumor tissue is not different from that in the normal tissue. However, the transmission of the incipient tumor tissue was lower than that of the normal tissue in THz imaging because the tumor tissue contained more water molecular clusters than the normal tissue. The tumor tissue became more permeable owing to the development of fibrous tissue around it. THz imaging will be more useful for discriminating liver tissues by increasing the spatial resolution.

The purpose of this study was to assess condylar fracture risk according to the classification of the mandibular inferior cortical shape using pantomography. This retrospective study was approved by the Institutional Review Board (EC15-12-009-1). 254 patients with suspected condylar fractures who underwent both pantomography and MDCT from April 2006 to December 2016 were included in this study. The mandibular inferior cortical shape was evaluated by pantomography on both sides of the mandible, distal to the mental foramen by specialist of two oral and maxillofacial radiologists, and classified into three types as follows; Type l: normal cortex, Type 2: mildly to moderately eroded cortex and Type 3: severely eroded cortex. Moreover, the patients were divided into two groups; Group I: normal bone mineral density (Type 1) and Group II: low bone mineral density (Types 2 and 3). Of the 254 patients, condylar fractures were seen in 158 patients (62.2%). Of the 158 patients with condylar fractures, 27 patients were in Group I (17.1%) and 131 patients were in Group II (82.9%). Of the 96 patients without mandibular fracture, 57 patients were in Group I (59.4%) and 39 patients were in Group II (40.6%). There was a statistically significant difference between Group I and Group II in the prevalence of condylar fractures (p < 0.05). Our results suggest that classification of the mandibular inferior cortical shape on pantomography may provide a risk assessment of condylar fractures.