Knowledge and risk perception of radiation for Japanese nursing students after the Fukushima Nuclear Power Plant disaster.

BACKGROUND: The Japanese have had three experiences of radiation disasters: the atomic bombs dropped on Hiroshima and Nagasaki in 1945, and the 2011 Fukushima Nuclear Power Plant disaster. The former two experiences have been covered in compulsory education programs. In light of these incidents, a strong fear of radiation has pervaded people of several generations. In such a situation, the role of nurses is important. When nurses treat residents, their attitudes change depending on how they understand and feel about radiation. The foundations of these attitudes are formed through student education. Hence, it is necessary to explore nursing students' understanding and risk perception of radiation, and the nature of radiation education received. OBJECTIVES: To assess the levels of understanding and risk perception of nursing students regarding radiation. DESIGN: Cross-sectional survey. METHODS: A questionnaire survey was administered to all students (74 first-year, 79 second-year, 65 third-year, and 69 fourth-year students) in the nursing department of a Japanese national university. The response rate was 84%. Respondents were asked to rate their level of understanding of 50 phrases chosen from two supplementary texts about radiation for elementary school students and for middle and high school students, prepared by the Japanese Ministry. Further, they were asked to rate their risk perception for 30 events, and to answer six questions about radiation. RESULTS: It was found that knowledge about radiation among Japanese nursing students was poor, because sufficient radiation education had not been provided. Hence, they displayed a greater fear of X-rays as compared to American students and members of the League of Woman Voters. However, it was also found that an increase in understanding might decrease risk perception. CONCLUSIONS: It was concluded that nursing students require adequate education about radiation, in order to reduce their fear of X-rays and to mitigate their risk perception.

Comparison of radiation risk perception and knowledge of radiation between Indonesian and Japanese dental students.

The purpose of the study was to obtain basic data to identify problems in radiation education in a situation where confidence in nuclear power has fluctuated over time and fear of nuclear power has increased globally due to nuclear power plant disasters at Chernobyl and Fukushima. We conducted a questionnaire survey on understanding and risk perception of radiation and atomic power, before and after lectures, for 107 Japanese and 137 Indonesian dental students. Thirty-six phrases were extracted from two supplementary texts about radiation created by the Japanese Ministry of Education, Culture, Sports, Science and Technology, and 30 events commonly used in research on risk perception were used. The students were asked to rate their level of understanding of 36 phrases and risk perception of 30 events. Moreover, the students were asked to answer 6 general questions about radiation. For Japanese students, understanding of radiation increased and risk perception for both nuclear power and X-rays decreased after lectures (p < 0.05). Concerning nuclear power, the risk-value declined as the level of understanding increased (p < 0.01). However, for Indonesian students, who had lectures on only radiation excluding nuclear power in dental radiology, risk perception increased for X-ray after lectures (p < 0.05). This indicates that thought and custom, in the absence of knowledge, are influenced by lectures. In general, it is said that increase in knowledge will lower risk perception, but even if radiation education is imparted, risk perception may rise if the lectures are not understood properly. It was concluded that educators need to incorporate sufficient knowledge in their teachings, and correct thinking, to mitigate the risk of future radiation education giving the opposite of the intended effect.

Availability of Japanese Government's supplemental texts on radiation reflecting the Fukushima Daiichi Nuclear Power Plant accident for elementary and secondary education from dental students' understanding.

Following the Fukushima Nuclear Power Plant accident, the Japanese government created two supplemental texts about radiation reflecting the accident for elementary, middle school, and high school students. These texts were made to explain radiation and consequently to obtain public consent for the continuation of the nuclear program. The present study aimed to evaluate the appropriateness of the content of the texts and to collect the basic data on the level of understanding necessary to improve radiation education. Lectures on radiology including nuclear energy and the Fukushima accident were given to 44 fourth-year dental students in 2013. The questionnaire was administered in 2014 when these students were in their sixth-year. The survey was also administered to 40 first-year students and 41 fourth-year students who hadn't any radiology lectures. Students rated their level of understanding of 50 phrases used in the texts on a four-point scale (understanding = 3, a little knowledge = 2, having heard = 1, no knowledge = 0). Questions on taking an advanced physics course in high school and means of learning about radiation in daily life were also asked. The level of understanding of phrases in the supplemental text for middle and high school students was significantly higher among sixth-year students (mean = 1.43) than among first-year (mean = 1.12) or fourth-year (mean = 0.93) students (p < 0.05). Overall, the level of understanding was low, with scores indicating that most students knew only a little. First-year students learning about radiation from television but four-year and six-year students learning about radiation from newspaper scored significantly higher (p < 0.05). It was concluded that radiation education should be improved by using visual material and preparing educators to teach the material for improving the public's understanding of radiation use-especially nuclear power generation because the phrases used in the supplementary texts are very difficult for students to understand.

Use of an advanced 3-T MRI movie to investigate articulation.

OBJECTIVE: To develop a magnetic resonance imaging (MRI) movie to reveal the dynamic movement of articulators and teeth. STUDY DESIGN: Five healthy females with normal occlusion participated in this study. Various concentrations of MRI contrast media (ferric ammonium citrate [FAC]) were tested for visualization of teeth, according to facial markers and with the use of a gel. Custom-made circuitry was connected to synchronize pronunciation of fricative sounds (/asa/) with scans. Three gradient echo sequences (True fast imaging with steady state precession [true FISP], FISP, and fast low angle shot [FLASH]) with a segmented cine were tested with the use of repetition times (TRs) of 9 ms and 31.5 ms. The MRI movie images were superimposed over the boundaries of teeth. The images produced during pronunciation, using the two different TRs (9 ms and 31 ms), were compared to assess the position of the lips and the tongue. RESULTS: Images obtained using the FLASH sequence, with a TR of 9 ms or 31.5 ms, can be used for diagnostic purposes. A TR of 9 ms, with 161 continuous images acquired, produced the highest-quality images of teeth, with few artifacts present. Pronunciation of the consonant "s" was clearly discernable. CONCLUSIONS: Our 3-T MRI movie system, with a temporal resolution less than 9 ms, can provide detailed information pertaining to variations in speech or oropharyngeal function.

Location dependency of the spatial resolution of cone beam computed tomography for dental use.

OBJECTIVE: This study evaluates the spatial resolution of cone beam computed tomography for dental use (CBCT) via modulation transfer function (MTF) analyses. STUDY DESIGN: Two models of CBCT system, 3DX FPD8 and FineCube v.12, were used. MTF analysis was applied to each CBCT system using a thin tungsten wire technique. RESULTS: The MTF curves in the radial direction on the XY-plane were concordant regardless of position, whereas the curves in the azimuthal direction tended to decrease as the distance from the rotation center increased. In the Z-axis direction, the MTF curve of the medial level of the field of view was superior to that of any other level. CONCLUSION: The spatial resolution of CBCT systems depends on the location within the field of view. Because the spatial resolution was the highest in the medial level and rotation center position, an object should be placed at this position during a CBCT examination.

Preoperative evaluation of patients with squamous cell carcinoma of the oral cavity: fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography and ultrasonography versus histopathology.

BACKGROUND: The purpose of this retrospective study was to compare fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and ultrasonography (US) in the staging of patients with squamous cell carcinoma of the oral cavity. METHODS: We compared preoperative evaluations regarding lymph nodes using PET/CT, US, and both methods. The cutoff for the maximum standardized uptake value (SUV(max)) in PET/CT was set at 2.7 by a receiver operating characteristic analysis that was based on the histopathological diagnosis. US was used to examine internal structural changes on B-mode and hilar vascularity on power Doppler. RESULTS: The performance of PET/CT and US in combination was better than that of each modality separately. However, there were histopathological changes that could not be detected on PET/CT or US. PET/CT could not detect nodes with necrotic or cystic changes. US could not detect lymph nodes that did not have abnormal structures. CONCLUSIONS: PET/CT and US are complementary tools to evaluate preoperative patients.

Magnetic resonance imaging of temporomandibular joint cyst.

OBJECTIVE: The objective of this study was to evaluate the magnetic resonance imaging (MRI) and clinical findings of 6 cases with synovial or ganglion cysts occurring in the temporomandibular joint (TMJ). STUDY DESIGN: Six patients with histopathologically confirmed TMJ cysts who were examined by MRI were included in this study. Two oral radiologists retrospectively evaluated MR images. RESULTS: MR images revealed a homogeneous well defined mass of the TMJ in all cases. These cysts demonstrated low signal intensity on proton density-weighted (PDW) and homogeneous very high signal on T2-weighted (T2W) images. They were all characteristically continuous with the joint capsule. Regarding clinical features, all 6 patients had some type of TMJ pain. CONCLUSIONS: TMJ cysts were identified as well defined homogeneous masses with low signal intensity on PDW and very high signal on T2W images, and characterized by continuity with the joint capsule. All of the patients with TMJ cysts exhibited some type TMJ pain.

Evaluation of selective tumor detection by clinical magnetic resonance imaging using antibody-conjugated superparamagnetic iron oxide.

Active targeting by monoclonal antibodies (mAbs) combined with nanosize superparamagnetic iron oxide (SPIO) is a promising technology for magnetic resonance imaging (MRI) diagnosis. However, the clinical applicability of this technology has not been investigated using appropriate controls. It is important to evaluate the targeting technology using widely used clinical 1.5-Tesla MRI in addition to the high-Tesla experimental MRI. In this study, we measured mAb-conjugated dextran-coated SPIO nanoparticles (CMDM) in vivo using clinical 1.5-Tesla MRI. MRI of tumor-bearing mice was performed using a simple comparison between positive and negative tumors derived from the same genetic background in each mouse. The system provided significant tumor-targeting specificity of the target tumor. To the best of our knowledge, this is the first report on the specific detection of target tumors by mAb-conjugated SPIO using clinical 1.5-Tesla MRI. Our observations provide clues for reliable active targeting using mAb-conjugated SPIO in clinical applications.

Shielding effect of a customized intraoral mold including lead material in high-dose-rate 192-Ir brachytherapy for oral cavity cancer.

A high-dose-rate (HDR) 192-Ir brachytherapy using a customized intraoral mold is effective for superficial oral cavity cancer, and the surrounding normal tissue is kept away from the radioactive source with gauze pads and/or mouth piece for reducing the dose on the normal tissues. In the Tokushima university hospital, the mold has a lead shield which utilizes the space prepared with sufficient border-molding by a specific dental technique using modeling compound. In HDR 192-Ir brachytherapy using a lead shielded customized intraoral mold, there are no reports measuring the absorbed dose. The purpose of the present study is to measure the absorbed dose and discuss the optimum thickness of lead in HDR 192-Ir brachytherapy using a customized intraoral mold with lead shield using a 1 cm thickness mimic mold. The thickness of lead in the mold could be changed by varying the arrangement of 0.1 cm thickness sheet of the acrylic resin plate and lead. The measured doses at the lateral surface of the mold with thermo-luminescence dosimeter were reduced to 1.12, 0.79, 0.57, 0.41, 0.31, 0.24 and 0.19 Gy and the ratios to the prescription dose were reduced to 56, 40, 29, 21, 16, 12 and 10 percent as lead thickness increased from 0 to 0.6 cm in 0.1 cm increments, respectively. A 0.3 cm thickness lead was considered to be required for a 1 cm thickness mold, and it was necessary to thicken the lead as much as possible with the constraint of limited space in the oral cavity, especially at the fornix vestibule.

High-dose-rate brachytherapy for patients with maxillary gingival carcinoma using a novel customized intraoral mold technique.

OBJECTIVE: The purpose of this study was to introduce a novel customized intraoral mold treatment for maxillary gingival carcinoma (UGC). STUDY DESIGN: Two patients with UGC were treated as salvage therapy using this technique. The mold was designed to keep normal soft tissues adjacent to the tumor away from the radioactive source as much as possible, and it was shielded by lead. The radiation dose on the buccal mucosa and tongue was measured at the inner and outer surfaces of the intraoral mold before starting high-dose-rate brachytherapy by the remote afterloading system, and was reduced to almost one tenth. RESULTS: The patient had no recurrence and no severe adverse effects on the normal soft tissue adjacent to the tumor until the end of the follow-up period. CONCLUSION: High-dose-rate brachytherapy using the novel customized intraoral mold might be a treatment option of not only salvage therapy, but definitive therapy of UGC.

Genetic analysis of the S1 gene of 4/91 type infectious bronchitis virus isolated in Japan.

S1 gene sequences for infectious bronchitis virus (IBV) strains of the 4/91 genotype (commonly called 793B) isolated from field outbreaks in Japan were analyzed to ascertain the relationship to 4/91 vaccine strain. Three field isolates (JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006) from flocks not immunized with a 4/91 type live IBV vaccine and one isolate (JP/Wakayama-2/2004) from a flock immunized with a 4/91 type live vaccine were examined. The amino acid identities among JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006 were about 98%, whereas the identities to the 4/91 vaccine strain and JP/Wakayama-2/2004 were about 90%. Three of the field isolates, JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006, were classified into a cluster closely related to French and Spanish isolates, but different from the cluster including the vaccine and JP/Wakayama-2/2004. These results indicate that JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006 were derived from foreign field isolates, but not from the vaccine strain. On the other hand, the S1 gene of JP/Wakayama-2/2004 revealed high sequence similarity with that of the 4/91 vaccine strain and appeared to be a vaccine-like virus derived from a vaccine. The field isolates of 4/91 genotype IBV could be distinguished from other genotypes by using the BalI and Pst I enzymes in addition to the polymerase chain reaction (PCR) -restriction fragment length polymorphism (RFLP) methods of Mase et al. [16] using Hae II and EcoR I enzymes. Furthermore, the 4/91 vaccine strain and vaccine-like isolate (JP/Wakayama-2/2004) could be differentiated from the other field isolates by Bgl II digestion. This method, therefore, would assist in identification of field isolates of the 4/91 genotype as outbreaks of IBV in vaccinated flocks.

MRI and clinical findings of posterior disk displacement in the temporomandibular joint.

OBJECTIVE: The objective of this study was to evaluate the magnetic resonance imaging and clinical findings of patients with posterior disk displacement in the temporomandibular joint. STUDY DESIGN: Magnetic resonance and clinical findings of 62 temporomandibular joints (44 patients) with posterior disk displacement were retrospectively analyzed. RESULTS: According to the criteria proposed by Westesson et al., 52 temporomandibular joints (84%) were the thin flat disk type and the remaining 10 (16%) were the perforated disk type. Fifteen temporomandibular joints (24%) had a history of luxation. Clicking was observed in 26 temporomandibular joints (42%), all of which were the thin flat disk type (chi-square test, P < .01). Pain was observed in 19% of patients with the thin flat disk type and 60% of those with the perforated disk type (P < .05). CONCLUSIONS: Magnetic resonance imaging could clearly reveal the details of posterior disk displacement in the temporomandibular joint. The clinical findings were dissimilar between the thin flat and the perforated disk type.

[Changes in shape of upper airway during titrated mandibular advancement: a magnetic resonance imaging study].

OBJECTIVE: To examine adaptive changes in the shape of the upper airway during titrated mandibular advancement. Furthermore, to understand the mechanism of mandible-adjustable therapy to improve the ventilation. METHODS: Fourteen non-apnea participated in the study. A custom-made oral device was used to keep the mandible in titrated advancement at 0% (F0), 50% (F50), 75% (F75), 100% (F100) of the maximum advancement. Magnetic resonance imaging was used to investigate the difference in the shape of upper-airway in these 4 positions. Changes in the anteroposterior direction (AP), lateral direction (Lat) and its ratio (AP/Lat) were calculated, which were transformed into the percentage of the original ones. RESULTS: The dose-dependent decrease of AP/Lat was found when the mandible was advanced (P = 0.0001). Lateral change rate in percentage increased by degrees (P = 0.0023), while the increase of anteroposterior change rate in percentage showed no statistical significance. CONCLUSION: The shape of upper airway tended to be less round. The enlargement of upper airway during titrated mandibular advancement was mainly the result of enlargement in lateral direction.

Trigeminal neuralgia: evaluation of neuralgic manifestation and site of neurovascular compression with 3D CISS MR imaging and MR angiography.

PURPOSE: To evaluate three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging and MR angiography with multiplanar reconstruction (MPR) for detection of neurovascular compression (NVC) in patients with trigeminal neuralgia and to evaluate the relationship between clinical symptoms related to trigeminal branches and those related to the site of trigeminal nerve compression. MATERIALS AND METHODS: Fifty-four consecutive patients with trigeminal neuralgia were examined at 3D CISS imaging and MR angiography with a 1.5-T MR system. Original transverse and four reformatted images were used for image interpretation. Vascular contact with the trigeminal nerve at the root entry zone (REZ) was determined, and the nature of the involved vessels was identified. The position of the blood vessel compressing the nerve was classified into cranial, caudal, medial, or lateral sites. Statistical analysis was performed with the chi2 test or the Fisher exact test between two groups and with the chi2 test among more than two groups. RESULTS: In 12 of 15 patients who underwent surgery, the artery that was considered a responsible vessel at 3D CISS imaging and MR angiography was confirmed as such. In the other three patients, the vein was the responsible vessel, which was detected only at 3D CISS imaging. Sixteen (89%) of 18 patients with symptoms related to the maxillary division had NVC at the medial site of the REZ, while 16 (76%) of 21 patients with symptoms related to the mandibular division had NVC at the lateral site (P <.001, chi2 test). CONCLUSION: 3D CISS MR imaging with MPR is useful in the detection of NVC in patients with trigeminal neuralgia, compared with MR angiography. A close relationship was found between the region of neuralgic manifestation and the site of trigeminal nerve compression.