Development of a novel method for visualizing restricted diffusion using subtraction of apparent diffusion coefficient values

In order to visualize restricted diffusion, the present study developed a novel method called 'apparent diffusion coefficient (ADC) subtraction method (ASM)' and compared it with diffusion kurtosis imaging (DKI). The diffusion-weighted images of physiological saline, in addtion to bio-phatoms of low cell density and the highest cell density were obtained using two sequences with different effective diffusion times. Then, the calculated ADC values were subtracted. The mean values and standard deviations (SD) of the ADC values of physiological saline, low cell density and the highest cell density phantoms were 2.95 +/- 0.08x10(-3), 1.90 +/- 0.35x10(-3) and 0.79 +/- 0.05x10(-3) mm(2)/sec, respectively. The mean kurtosis values and SD of DKI were 0.04 +/- 0.01, 0.44 +/- 0.13 and 1.27 +/- 0.03, respectively. The ASM and SD values were 0.25 +/- 0.20x10(4), 0.51 +/- 0.41x10(4) and 4.80 +/- 4.51x10(4) (sec/mm(2))(2), respectively. Using bio-phantoms, the present study demonstrated that DKI exhibits restricted diffusion in the extracellular space. Similarly, ASM may reflect the extent of restricted diffusion in the extracellular space

Development and Evaluation of a Short-time Imaging Method for the Clinical Study of the Apparent Diffusion Coefficient Subtraction Method

The apparent diffusion coefficient subtraction method (ASM) was developed as a new restricted diffusionweighted imaging technique for magnetic resonance imaging (MRI). The usefulness of the ASM has been established by in vitro basic research using a bio-phantom, and clinical research on the application of the ASM for the human body is needed. Herein, we developed a short-time sequence for ASM imaging of the heads of healthy volunteers (n=2), and we investigated the similarity between the obtained ASM images and diffusion kurtosis (DK) images to determine the utility of the ASM for clinical uses. This study appears to be the first to report ASM images of the human head. We observed that the short-time sequence for the ASM imaging of the head can be scanned in approx. 3 min at 1.5T MRI. The noise reduction effect of median filter processing was confirmed on the ASM images scanned by this sequence. The obtained ASM images showed a weak correlation with the DK images, indicating that the ASM images are restricted diffusion-weighted images. The new shorttime imaging sequence could thus be used in clinical studies applying the ASM

Evaluation of the Imaging Process for a Novel Subtraction Method Using Apparent Diffusion Coefficient Values

Diffusion-weighted imaging may be used to obtain the apparent diffusion coefficient (ADC), which aids the diagnosis of cerebral infarction and tumors. An ADC reflects elements of free diffusion. Diffusion kurtosis imaging (DKI) has attracted attention as a restricted diffusion imaging technique. The ADC subtraction method (ASM) was developed to visualize restricted diffusion with high resolution by using two ADC maps taken with different diffusion times. We conducted the present study to provide a bridge between the reported basic ASM research and clinical research. We developed new imaging software for clinical use and evaluated its performance herein. This software performs the imaging process automatically and continuously at the pixel level, using ImageJ software. The new software uses a macro or a plugin which is compatible with various operating systems via a Java Virtual Machine. We tested the new imaging software’s performance by using a Jurkat cell bio-phantom, and the statistical evaluation of the performance clarified that the ASM values of 99.98% of the pixels in the bio-phantom and physiological saline were calculated accurately (p<0.001). The new software may serve as a useful tool for future clinical applications and restricted diffusion imaging research

New field‑in‑field with two reference points method for whole breast radiotherapy: Dosimetric analysis and radiation‑induced skin toxicities assessment

The usefulness of the field‑in‑field with two reference points (FIF w/ 2RP) method, in which the dose reference points are set simultaneously at two positions in the irradiation field and the high‑dose range is completely eliminated, was examined in the present study with the aim of decreasing acute skin toxicity in adjuvant breast radiotherapy (RT). A total of 573 patients with breast cancer who underwent postoperative whole breast RT were classified into 178 cases with wedge (W) method, 142 cases with field‑in‑field without 2 reference points (FIF w/o 2RP) method and 253 cases with FIF w/ 2RP method. Using the FIF w/ 2RP method, the high‑dose range was the lowest among the three irradiation methods. The planning target volume (PTV) V105% and the breast PTV for evaluation (BPe) V105% decreased to 0.09 and 0.10%, respectively. The FIF w/ 2RP method vs. the FIF w/o 2RP method had a strong association (η) with PTV V105% (η=0.79; P<0.001) and BPe V105% (η=0.76; P<0.001). The FIF w/ 2RP method had a significant impact on lowering the skin toxicity grade in weeks 3 and 4, and increasing the occurrence of skin toxicity grade 0. The FIF w/ 2RP method vs. the W method had a moderate association with skin toxicity grade at week 3 (η=0.49; P<0.001). Using the FIF w/ 2RP method, the high‑dose range V105% of the target decreased to 0%, and skin adverse events were decreased in conjunction. For patients with early‑stage breast cancer, particularly patients with relatively small‑sized breasts, the FIF w/ 2RP method may be an optimal irradiation method

Investigation into the Effect of Breast Volume on Irradiation Dose Distribution in Asian Women with Breast Cancer

Reports on irradiation dose distribution in breast cancer radiotherapy with sufficient sample size are limited in Asian patients. Elucidating dose distribution in Asian patients is particularly important as their breast volume differs compared to patients in Europe and North America. Here, we examined dose distribution in the irradiation field relative to breast volume for three irradiation methods historically used in our facility. We investigated the influence of breast volume on each irradiation method for Asian women. A total of 573 women with early-stage breast cancer were treated with breast-conserving surgery and adjuvant radiotherapy. Three methods were compared: wedge (W), field-in-field (FIF), and wedge-field-in-field (W-FIF). In patients with small breast volume, FIF decreased low- and high-dose areas within the planning target volume, and increased optimal dose area more than W. In patients with medium and large breast volumes, FIF decreased high-dose area more than W. The absolute values of correlation coefficients of breast volume to low-, optimal-, and high-dose areas and mean dose were significantly lower in FIF than in W. The correlation coefficients of V107% were 0.00 and 0.28 for FIF and W, respectively. FIF is an excellent irradiation method that is less affected by breast volume than W in Asian breast cancer patients

The Holocene humid period in the Nefud Desert: Hunters and herders in the Jebel Oraf palaeolake basin, Saudi Arabia

Archaeological surveys and excavations in the Jebel Oraf palaeolake basin, north-western Saudi Arabia, have identified a well-preserved early- to mid-Holocene landscape. Two types of occupation site can be distinguished: nine small and ephemeral scatters from single occupation phases on the slopes of sand dunes and three hearth sites indicative of repeated occupation on palaeolake shorelines. In addition, 245 rock art panels, 81 cairns, and 15 stone structures were recorded. This diverse dataset provides an opportunity to reconstruct occupation patterns and changes in landscape use. A particularly important site, Jebel Oraf 2, documents two episodes of lake high stands at ca. 6500 BC and 5300 BC, flooding parts of the locality. Neolithic pastoralists likely occupied the site after the end of the wet season, when the terrain was dry. Earlier sites are located in dune embayments some 7–14 m above the shore of the palaeolake. These locations are consistent with hunting strategies identifiable in the rock art that suggest wildlife was ambushed at watering places. Later rock art at Jebel Oraf also documents the hunting of wild camel in the Iron Age. The lithic industries documented in the Jebel Oraf basin support arguments of repeated contact with Levantine populations

STUDENT-CENTERED LEARNING PEDAGOGY AS INNOVATIVE PLACE MAKER IN CAMPUS : Facility Management Research on Learning Spaces

application/pdfSpaces for learning in Japanese universities are inevitably changing; this change is part of a worldwide trend. The changes are caused mainly by adopting student-centered learning pedagogies -namely Problem Based Learning (PBL), in addition to the emergence of a new generation of campus users and introduction of Information Technology (IT) tools and applications in all aspects of life. This study tried to tackle the issues of Facility Management (FM) within university campus, the focus to be on studying the use of campus formal and informal learning spaces including common place, library learning commons and PBL classes. The primary issue guiding this study was how to create learning spaces that correspond with the increased use of innovative student-centered learning pedagogies and encourage effective collaboration between campus users; this meant the necessity of studying the physical and the social components of such learning spaces. Acquiring such information can enrich the developing knowledge of facility management in the field of campus planning and design. This study was qualitative in nature and included the use of techniques of visual documentation, observation, time-lapse photography, behavioral mapping and video recording. In the study of actual behaviors in outdoor common place structured observation was followed as a method based on time-lapse photography, while the study of dining facilities and PBL classes made use of observation sessions conducted by video recording. As for the study of users’ activities in learning commons, the study was conducted using behavioral mapping.The research showed that there was a misfit between new student-centered learning pedagogies and current learning environments especially in classrooms. Place making is an important element in creating successful campus formal and informal learning environments. The notion of student-centered learning pedagogy as a new place maker in campus universities is global; such pedagogies -namely PBL- are being adopted in higher education institutions all over the world in various disciplines, this notion may be applied anywhere taking into consideration the context of each particular university. Place making in addition to its concern with physical features refers to the social and emotional meanings experienced in a setting by its habitual users. Campuses of effective learning spaces based on place making help to shape the people of tomorrow, since such buildings are where the students of today gain knowledge that builds their personalities and prepares them for their professional lives. Sitting places in outdoor common places should be studied in terms of location, layout and comfort; also the use of natural elements and providing people drawing activities is essential to succeed. Dining facilities should incorporate more seating alternatives taking into account the groups served, also the notion of common place can be supported by creating flexible meal blocks and easing congestion. The introduction of learning commons into many libraries in Japanese universities is the clearest demonstration of change in campus learning spaces. Learning commons must include a mixture of individual and group work areas. Use of flexible furniture, spaciousness and providing wide enough movement spines, in addition to incorporating IT tools is necessary to create inspiring learning commons. Classrooms need to be changed to cope with PBL processes. Using sociopetal flexible table configurations to accommodate various group sizes is essential to create conversational learning environments. Territoriality and privacy needs of students can be met by providing enough work table surface area. Supplying each group with a PC and a projector can facilitate using IT tools collaboratively. Effective collaboration entails being engaged in a repetitive pattern of activities and learning behaviors, during collaboration talking among group plays a pivotal role to guarantee smooth task sharing and successful problem solving. Students learning behaviors preference and engagement levels were affected by students learning styles. The facility managers in campus should take actual uses and behaviors of its frequent users into consideration to create effective learning spaces.三重大学大学院工学研究科博士後期課程建築学専攻258