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A three-dimensional investigation of mandibular deviation in patients with mandibular prognathism
Kazuaki Osawa,Hideyoshi Nishiyama,Kojiro Takahashi,Ayako Honda,Chihiro Atarashi,Ritsuo Takagi,Tadaharu Kobayashi,Isao Saito,Jun Nihara 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-
Background Craniofacial disharmony in cases of jaw deformity associated with abnormal lateral deviation of the jaw mostly involves both the maxilla and mandible. However, it has been still difficult to capture the jaw deviation aspect in a 3-dimensional and quantitative techniques. In this study, we focused on 3-dimensional mandibular morphology and position of the condylar head in relation to the base of the skull in patients with mandibular prognathism, one of the most common jaw deformities. We used cluster analysis to quantify and classify deviation and clarified its characteristics. We also investigated the degree of correlation between those findings and menton (Me) deviation measured on frontal cephalograms, which is a conventional indicator of jaw deformity. Results Findings obtained from 100 patients (35 men, 65 women) were classified into the following three groups based on mandibular morphology and condylar position relative to the skull base. Then, reclassification using these parameters enabled classification of cluster analysis findings into seven groups based on abnormal jaw deviation characteristics. Comparison among these seven groups showed that the classification criteria were ramus height, mandibular body length, distance from the gonion to the apex of the coronoid process, and the lateral and vertical positions of the mandible. Weak correlation was also found between Me deviation on frontal cephalograms and each of the above parameters measured on 3D images. Conclusions Focusing on mandibular morphology and condylar position relative to the skull base in patients with mandibular prognathism, we used cluster analysis to quantify and classify jaw deviation. The present results showed that the 3D characteristics of the mandible based on mandibular morphology and condylar position relative to the skull base can be classified into seven groups. Further, we clarified that Me deviation on frontal cephalograms, which has been used to date, is inadequate for capturing jaw deviation characteristics.
Prompt gamma detection for range verification in proton therapy
Shunsuke Kurosawa,Hidetoshi Kubo,Kazuki Ueno,Shigeto Kabuki,Satoru Iwaki,Michiaki Takahashi,Kojiro Taniue,Naoki Higashi,Kentaro Miuchi,Toru Tanimori,김도균,김종원 한국물리학회 2012 Current Applied Physics Vol.12 No.2
It is an on-going challenge to verify the proton range in situ during proton therapy. Since the protons stop in target tissue, measurement of gamma-rays emitted either promptly from nuclear de-excitation or in pair from positron annihilation is the feasible method to monitor the proton range in-vivo. Using the technique of gamma collimation, we empirically demonstrated that the proton range and prompt gamma distribution are well correlated in the therapy energy range, and that measuring prompt gammas is a viable method for the clinical application. However, this collimation technique appears not to be applicable to passively scattered proton beams. The device chosen for gamma imaging in 2D is an electron tracking Compton camera, which images single-emission photons employing a gas chamber to induce Compton scattering. Images of prompt gammas were attained at the proton beam energy of 140 MeV. Measurements showed that gamma image in the energy range of 800e2000 keV provides a better match with the proton range compared to the image by lower energy gammas.