A key-point based real-time tracking of lung tumor in x-ray image sequence by using difference of Gaussians filtering and optical flow.

In radiation therapy, for accurate radiation dose delivery to a target tumor and reduction of the extra exposure of normal tissues, real-time tumor tracking is typically an important technique in lung cancer treatment since lung tumors move with patients' respiration. To observe a tumor motion in real time, x-ray fluoroscopic devices can be employed, and various tracking techniques have been proposed to track tumors. However, development of a fast and accurate tracking method for clinical use is still a challenging task since the obscured image of the tumor can cause decreased tracking accuracy and can result in additional processing time for remedying the accuracy. In this study, a new key-point-based tumor tracking method, which is sufficiently fast and accurate, is presented. Given an x-ray image sequence, the proposed method employs a difference-of-Gaussians filtering technique to detect key points in the tumor region of the first frame which are robust against noise and outliers in the subsequent frames. In the subsequent frames, these key points are tracked using a fast optical flow technique, and tumor motion is estimated via their movement. To evaluate the performance, the proposed method has been tested on several clinical kV and MV x-ray image sequences. The experimental results showed that the average of the root mean square errors of tracking were [Formula: see text] and [Formula: see text] for kV and MV x-ray image sequences, respectively. This tracking performance was more accurate than previous tracking methods. In addition, the average processing times for each frame were [Formula: see text] and [Formula: see text] for kV and MV image sequences, respectively, and the proposed method was faster than previous methods as well as shorter than frame acquisition interval. Therefore, the proposed method has the potential for both highly accurate and fast tumor tracking in clinical applications.

Issues with the surgical treatment of antiresorptive agent-related osteonecrosis of the jaws.

Antiresorptive agent-related osteonecrosis of the jaw is a rare but significant complication in patients using antiresorptive agents such as bisphosphonates and denosumab. Although the disease is well recognized, and many studies have been performed on the management of this condition, the treatment of severe osteonecrosis is still a challenge. Most recent studies have shown an advantage of surgical treatment over conservative treatment for stage 2/3 patients, but there is no consensus on the appropriate surgical procedures for antiresorptive agent-related osteonecrosis of the jaw. Furthermore, patients with severe systemic conditions may not be appropriate for extensive surgical treatment, and the treatment protocol for such patients has not been established. In this review, issues regarding the current surgical treatment for antiresorptive agent-related osteonecrosis of the jaws are discussed, with an emphasis on the clinical aspects.

DEVELOPMENT OF A HIGH-EFFICIENCY PROTON RECOIL TELESCOPE FOR D-T NEUTRON FLUENCE MEASUREMENT.

A high-efficiency proton recoil telescope was developed to determine neutron fluences in neutron fields using the 3H(d,n)4He reaction. A 2-mm thick plastic scintillation detector was employed as a radiator to increase the detection efficiency and compensate for the energy loss of the recoil proton within. Two silicon detectors were employed as the ΔE and E detectors. The distance between the radiator and the E detector was varied between 50 and 150 mm. The telescope had detection efficiencies of 3.5 × 10-3 and 7.1 × 10-4 cm2 for distances of 50 and 100 mm, respectively, which were high enough to determine the neutron fluence in 14.8-MeV neutron fields, with a few thousand cm-2 s-1 fluence rate, within a few hours.

Photon dose mixed in monoenergetic neutron calibration fields using 7Li(p,n)7Be reaction.

The ambient dose equivalents H*(10) of photons mixed in the 144, 250 and 565 keV monoenergetic neutron fields were evaluated using measurements from an NaI(Tl) detector and calculations done using the MCNP-ANT code. It was found that H*(10) of the photons produced in the target assembly dominates the dose, particularly near the target. The H*(10) of the photons produced in other materials in the field increases with the increase in distance from the target and could not be neglected at a large distance from the target. The ratios of the H*(10) of the mixed photons to that of the monoenergetic neutrons for 144, 250 and 565 keV neutron fields, were evaluated to be below 5.5, 6.9 and 1.5 %, respectively. The ratios were calculated at calibration points between 100 and 500 cm from the target.

Development of portable long counter with two different moderator materials.

A portable, light-weight long counter (LC) with small dimensions was developed. This LC consists of a (3)He thermal neutron counter, a cylindrical moderator and outer shields. It was designed to have an almost flat response in a neutron energy range of 0.4 eV to 5 MeV. The portable LC has a radius of 11 cm and a length of 39 cm. Its weight was successfully reduced to 15 kg. Polystyrene was employed instead of polyethylene for the front part of the moderator in order to increase the sensitivity to low-energy neutrons. The response function calculated using the MCNP code was consistent with the results of experiments using monoenergetic neutron calibration fields.

Lack of changes in carotid artery compliance with systemic nitric oxide synthase inhibition.

Proximal large elastic arteries (ascending aorta and carotid artery) have an important role in buffering the pulsatile pressure generated from the left ventricle, which forwards continuous peripheral blood flow and protects the brain microcirculation from end-organ damage. Although compliance of distal conduit arteries (extremities' arteries) is attenuated by the nitric oxide synthase (NOS) inhibition, it is yet unknown whether compliance of proximal elastic arteries changes by the systemic NOS inhibition. To address this question, we measured central artery compliance in 17 young adults (26±1 years) who underwent intravenous infusions of N(G)-monomethyl-L-arginine (L-NMMA) or saline (placebo) on separate days. Following the systemic NOS inhibition, the mean arterial pressure (MAP), total peripheral resistance and aortic augmentation index were significantly increased. However, carotid artery compliance was not affected significantly (from 0.10±0.01 to 0.11±0.01 mm2) per mmHg) and the ß-stiffness index (an index of arterial compliance adjusted for the distending pressure) tended to decrease (from 6.63±0.35 to 6.06±0.42 a.u., P=0.07). These parameters were not altered with saline infusion. Changes in the ß-stiffness index tended to correlate negatively with the corresponding changes in MAP (r = -0.31, P=0.07). These results suggest that carotid artery compliance remains unchanged during the systemic NOS inhibition in spite of systemic vasoconstriction.

An attempt to decrease anisotropic emissions of neutrons from a cylindrical 241Am-Be-encapsulation source.

An attempt to decrease the anisotropic emissions of neutrons from a cylindrical (241)Am-Be-encapsulated X3 source was conducted with Monte Carlo calculations and experiments. The influence of metal materials and shapes of the external casing to the anisotropy factor were focussed on. Results obtained by calculations using MCNP4C implied that a light and spherical-shaped external casing decreases the anisotropic emission of neutrons. Experimental results using the spherical-shaped aluminium protection case also revealed that the anisotropy factor was close to 1.0 with wide zenith angle ranges.

SU-E-J-135: 3-D Fourier-Based Volumetric Registration for Estimating Intra-Fractional Lung Tumor Motion.

PURPOSE: To develop a three-dimensional (3-D) volumetric registration algorithm to estimate the intra-fractional lung tumor motion between respiratory phases for improving the accuracy of radiotherapy treatment. METHODS: The 3-D thoracic CT volumes (512×512×160 voxels, with dimensions 0.97×0.97×2.5 mm3 ) in different respiratory phases were acquired on a General Electric Optima T580 scanner in cine mode. As a preprocess, a bicubic interpolation was used to interpolate the original 3-D volumes along the cephalo-caudal axis to volumes of size 512×512×400 voxels, with dimensions 0.97×0.97×1 mm3 . In each respiratory phase, a sub-volume covering the tumor was roughly specified manually. A 3-D phase correlation of two sub-volumes was computed by using the 3-D inverse Fourier transformation of the normalized cross power spectrum of two sub-volumes. The 3-D displacements along three axes were estimated by finding the location of the highest peak in the 3-D phase correlation. RESULTS: Experiments were conducted on an artificial 4-D CT data set and three clinical 4-D CT data sets. Experimental results shown that the proposed algorithm was capable of estimating the tumor motion between respiratory phases with a high-accuracy (mean square error <1 mm). CONCLUSIONS: This work extended the conventional image registration techniques from 2-D to 3-D for tumor motion estimation. This work indicates a potential for significant accuracy improvement in radiotherapy treatment planning. The high-accurate 3-D tumor motion information provides a reliable basis for expanding a clinical target volume (CTV) to a planning target volume (PTV) to incorporate the intra-fractional tumor motion.

SU-D-BRA-02: An Extended Time-Variant Seasonal Autoregressive Model-Based Prediction for Irregular Breathing Motion Tracking.

PURPOSE: Real-time tumor position/shape measurement and dynamic beam tracking techniques allow accurate and continuous irradiation to moving tumor, but there can be a delay of several hundred milliseconds between observation and irradiation. A time-variant seasonal autoregressive (TVSAR) model has been proposed for compensating the delay by predicting respiratory tumor motion with sub-millimeter accuracy for a second latency. This is the-state-of-the-art model for almost regular breathing prediction so far. In this study, we propose an extended prediction method based on TVSAR to be usable for various breathing patterns, by predicting the residual component obtained from conventional TVSAR. METHODS: An essential core of the method is to take into account the residual component that is not predictable by only TVSAR. The residual component involves baseline shift, amplitude variation, and so on. In this study, the time series of the residual obtained for every new sample are predicted by using autoregressive (AR) model. The order and parameters of the AR model is adaptively determined for each residual component by using an information criterion. Eleven data sets of 3-D lung tumor motion, observed at Georgetown University Hospital by using Cyberknife Synchrony system, were used for evaluation of the prediction performance. RESULTS: Experimental results indicated that the proposed method is superior to those of conventional and the state-of-the-art methods for 0 to 1 s ahead prediction. The average prediction error of the proposed method was 0.920 plus/minus 0.348 mm for 0.5 s forward prediction. CONCLUSION: We have developed the new prediction method based on TVSAR model with adaptive residual prediction. The new method can predict various respiratory motions including not only regular but also a variety of irregular breathing patterns and thus can compensate the bad effect of the delay in dynamic irradiation system for moving tumor tracking. A part of this work has been financially supported by Varian Medical Systems Inc., Palo Alto, CA and Japan Society for the Promotion of Science (JSPS), Japan.

Examination of mitral regurgitation with a goat heart model for the development of intelligent artificial papillary muscle.

Annuloplasty for functional mitral or tricuspid regurgitation has been made for surgical restoration of valvular diseases. However, these major techniques may sometimes be ineffective because of chamber dilation and valve tethering. We have been developing a sophisticated intelligent artificial papillary muscle (PM) by using an anisotropic shape memory alloy fiber for an alternative surgical reconstruction of the continuity of the mitral structural apparatus and the left ventricular myocardium. This study exhibited the mitral regurgitation with regard to the reduction in the PM tension quantitatively with an originally developed ventricular simulator using isolated goat hearts for the sophisticated artificial PM. Aortic and mitral valves with left ventricular free wall portions of isolated goat hearts (n=9) were secured on the elastic plastic membrane and statically pressurized, which led to valvular leaflet-papillary muscle positional change and central mitral regurgitation. PMs were connected to the load cell, and the relationship between the tension of regurgitation and PM tension were measured. Then we connected the left ventricular specimen model to our hydraulic ventricular simulator and achieved hemodynamic simulation with the controlled tension of PMs.

Multi-Component Structure of Roland-Morris Disability Questionnaire (RDQ), a Lumbago-Specific QOL (Quality of Life) Measure.

Lumbago is one of the most prevalent symptoms in patients with osteoporotic vertebral fracture. Roland-Morris Disability Questionnaire (RDQ) is a quality of life (QOL) questionnaire targeted for evaluating lumbago. Although total score is the usual way of analysis, we have tried to make more use of it by subscale analysis. Forty-four osteoporotic patients were evaluated for their QOL using RDQ and SF-8; a widely accepted generic (non disease-specific) QOL questionnaire. Subscales and summary scores of SF-8 were significantly lower than Japanese norm. Patients with fracture had significantly lower scores including RDQ. Multiple regression analysis has shown that total score of RDQ was significantly contributed by bodily pain as well as other subscales of SF-8. Principal component analysis has revealed that RDQ consists of two components representing general, and mental or social aspect of lumbago. Defining the component structure and determining the procedure to obtain the subscales would make the most use of RDQ, and contribute to the better evaluation of patients with lumbago.

Structural design of a newly developed pediatric circulatory assist device for Fontan circulation by using shape memory alloy fiber.

Total cavopulmonary connection (TCPC) is commonly applied for the surgical treatment of congenital heart disease such as single ventricle in pediatric patients. Patients with no ventricle in pulmonary circulation are treated along with Fontan algorithm, in which the systemic venous return is diverted directly to the pulmonary artery without passing through subpulmonary ventricle. In order to promote the pulmonary circulation after Fontan procedure, we developed a newly designed pulmonary circulatory assist device by using shape memory alloy fibers. We developed a pulmonary circulatory assist device as a non-blood contacting mechanical support system in pediatric patients with TCPC. The device has been designed to be installed like a cuff around the ePTFE TCPC conduit, which can contract from outside. We employed a covalent type functional anisotropic shape memory alloy fiber (Biometal, Toki Corporation, Tokyo Japan) as a servo actuator of the pulmonary circulatory assist device. The diameter of this fiber was 100 microns, and its contractile frequency was 2-3 Hz. Heat generation with electric current contracts these fibers and the conduit. The maximum contraction ratio of this fiber is about 7% in length. In order to extend its contractile ratio, we fabricated and installed mechanical structural units to control the length of fibers. In this study, we examined basic contractile functions of the device in the mock system. As a result, the internal pressure of the conduit increased to 63 mmHg by the mechanical contraction under the condition of 400 msec-current supply in the mock examination with the overflow tank of 10 mmHg loading.

Clinical study on prognostic factors for autotransplantation of teeth with complete root formation.

Autotransplantation is often performed to replace a missing tooth, but tooth autotransplantation has been reported in fewer teeth with complete root formation than those with incomplete root formation. The aim of this prospective study was to evaluate the factors that affect the prognosis of autotransplantation of teeth with complete root formation. 109 patients with 117 transplants were studied. Of the 117 transplants investigated, 14 (12%) failed during the observation period. The overall 1-year survival rate was 96%; the 5-year survival rate was 84%. The major causes of failure were unsuccessful initial healing and replacement root resorption with periodontal inflammation. Factors significantly associated with unsuccessful transplantation, in single factor analysis, were age 40 years or more, molar tooth as donor, probing pocket depth to 4mm or more, history of root canal treatment, multi-rooted teeth and fixation with sutures. Pocket depth of 4mm or more and history of root canal treatment appeared to increase the risk of unsuccessful transplantation in multivariate analysis. It is suggested that the pocket depth of the donor tooth and history of root canal treatment are related to the healing of paratransplantal tissue and root resorption.

Application of the segment weight dynamic movement method to the normalization of gait EMG amplitude.

This study aims at determining the applicability of a segment weight dynamic movement (SWDM) method as an alternative for normalizing gait EMGs in comparison with the conventional isometric maximal voluntary contraction (MVC) method. The SWDM method employs reference exercises, each being a dynamic, repetitive movement of a joint under the load of the segment weight (i.e., the total weight of all segments distal to the joint). EMG amplitudes of 28 healthy male subjects walking at 120 steps/min were normalized by the two methods. CV and VR were used to assess the inter-individual variability of both the normalized gait EMG for 8 muscles. The CV and VR values attained with the two methods were close to each other, as well as to those obtained by other researchers using the isometric MVC method. These results suggest that the SWDM method has a comparable level of applicability to gait EMG normalization as the isometric MVC method.

Assessment of synchronization measures for effective ventricular support by using the shape memory alloy fibred artificial myocardium in goats.

Thromboembolic and haemorrhagic complications are the primary causes of mortality and morbidity in patients with artificial hearts, which are known to be induced by the interactions between blood flow and artificial material surfaces. The authors have been developing a new mechanical artificial myocardial assist device by using a sophisticated shape memory alloy fibre in order to achieve the mechanical cardiac support from outside of the heart without a direct blood contacting surface. The original material employed as the actuator of artificial myocardial assist devices was 100um fibred-shaped, which was composed of covalent and metallic bonding structure and designed to generate 4-7 % shortening by Joule heating induced by the electric current input. In this study, we focused on the synchronization of the actuator with native cardiac function, and the phase delay parameter was examined in animal experiments using Saanen goats. Total weight of the device including the actuator was around 150g, and the electric power was supplied transcutaneously. The device could be successfully installed into thoracic cavity, which was able to be girdling the left ventricle. The contraction of the device could be controlled by the originally designed microcomputer. The mechanical contraction signal input had been transmitted with the phase delay of 50-200 msec after the R-wave of ECG, and hemodynamic changes were investigated. Cardiac output and systolic left ventricular pressure were elevated with 20% delay of cardiac cycle by 27% and 7%, respectively, although there was smaller difference under the condition of the delay of over 30%. Therefore, it was suggested that the synchronization measures should be examined in order to achieve sophisticated ventricular passive/active support on physiological demand.

Involvement of endothelin-1 in habitual exercise-induced increase in arterial compliance.

AIM: Habitual aerobic exercise results in a significant increase in central arterial compliance. Endothelin-1 (ET-1) is a potent endothelium-derived vasoconstrictor peptide and could play a role in mediating the habitual aerobic exercise-induced increase in central arterial compliance. The aim of the present study was to examine whether ET-1 is involved in the mechanisms underlying the increase in central arterial compliance with aerobic exercise training. METHODS: Seven apparently healthy middle-aged and older (60 +/- 3 years) adults underwent systemic endothelin-A/B (ET(A/B))-receptor blockade (500 mg of Tracleer) before and after 12 weeks of aerobic exercise training (70 +/- 1% of maximal heart rate, 44 +/- 2 min day(-1), 4.4 +/- 0.1 days week(-1)). RESULTS: Basal carotid arterial compliance (via simultaneous B-mode ultrasound and arterial applanation tonometry on the common carotid artery) increased significantly after exercise training. Resting plasma ET-1 concentration decreased significantly after exercise training. Before exercise intervention, carotid arterial compliance increased significantly with the administration of the ET(A/B)-receptor blockade. After training, however, increases in carotid arterial compliance previously observed with the ET(A/B)-receptor blockade before training were abolished. CONCLUSIONS: Regular aerobic exercise training enhances central arterial compliance in middle-aged and older humans. The increase in arterial compliance was associated with the corresponding reduction in plasma ET-1 concentration as well as the elimination of ET-1-mediated vascular tone. These results suggest that reductions in ET-1 may be an important mechanism underlying the beneficial effect of exercise training on central artery compliance.

Effect of 12 weeks of moderate-intensity resistance training on arterial stiffness: a randomised controlled trial in women aged 32-59 years.

BACKGROUND: Resistance training has been increasingly incorporated into the overall exercise programme because of its effect on muscle strength, functional capacity and osteoporosis. High-intensity resistance training increases arterial stiffness. However, the effect of moderate-intensity resistance training on arterial stiffness is unknown. OBJECTIVE: To determine whether 12 weeks of moderate-intensity resistance training increases arterial stiffness in middle-aged women. METHODS: 35 middle-aged women (age range 32 to 59 years) volunteered to participate. The subjects were randomly assigned to one of three groups: resistance training (RT) group, aerobic exercise training (AET) group or control group. The RT and AET groups performed 12 weeks of moderate-intensity resistance training or aerobic exercise training (two days/week). RESULTS: In the RT group, one-repetition maximum strength significantly increased after the intervention. Interestingly, aortic (carotid-femoral) pulse wave velocity (PWV; an index of arterial stiffness), and peripheral (femoral-ankle) PWV did not change with moderate-intensity resistance training. In contrast, in the AET group, carotid-femoral PWV significantly decreased after the intervention. Resistance training and aerobic exercise training did not affect blood pressure. CONCLUSIONS: This study found that moderate-intensity resistance training did not increase arterial stiffness in middle-aged women, which may have great importance for health promotion with resistance training.

Genomic organization, expression and evolution of porcine CRSP1, 2, and 3.

Recently we identified and characterized porcine calcitonin receptor-stimulating peptide (CRSP) 1, CRSP2 and CRSP3 as members of the calcitonin/calcitonin gene-related peptide (CT/CGRP) family. In the present study, the genomic sequences and organization of CRSP1, 2, and 3 were determined, and the expression of the genes in the porcine brain was investigated using in situ hybridization. Analysis of 5'-upstream regions of the three CRSPs demonstrated that CRSP1 and CRSP2 have almost identical sequences (>98% similarity) and high sequence similarities including functional transcription binding sites with the corresponding region of human CALCA (CT/alpha CGRP), whereas CRSP3 retains less similarity with the above genes. RH mapping of CRSPs demonstrated that they resided in a region of swine chromosome 2 (SSC2). The arrangement of the genes in the region was found to be conserved in corresponding human and mouse regions. In situ hybridization demonstrated sense transcripts of the three genes in cerebrum, hippocampus, hypothalamus, pons/midbrain, and thalamus of 3-month-old pigs, and CRSP2 sense transcripts additionally in tractus opticus. The sense transcripts of alpha CGRP and CALCB (beta CGRP) were detected in cerebrum, hippocampus, and pons/midbrain of newborn mice, and to a lesser extent in pons/midbrain of 8-week-old mice. These results taken together with the chromosomal conservation and phylogenetic clustering of CT/CGRP family indicate that CRSP1, 2, and 3 may be functionally different from alpha CGRP and beta CGRP, though they are indicated to have a common progenitor gene.

Heat island mitigation using water retentive pavement sprinkled with reclaimed wastewater.

In Japan, reclaimed wastewater has been recycled widely for non-potable urban applications and it is to be used for sprinkling roads to mitigate heat island in urban areas. To assess the heat island mitigation effects of the sprinkling reclaimed wastewater on water retentive pavement, we carried out a survey at Shiodome-District, Tokyo. The temperatures of air and roads, humidity, and WBGT (Wet-bulb globe temperature) were measured and heat flux was estimated to compare the condition of the areas with/without sprinkling. The following results were obtained. 1) Sprinkling reclaimed wastewater decreased the road surface temperature by 8 degrees during the daytime and by 3 degrees at night: temperatures equal to those on planting zones. Nevertheless sprinkling was done only in the daytime, the temperature decrease effect was not only obtained during the daytime: it continued through the night, due to the water retentive pavement. 2) Sprinkling reclaimed wastewater reduced the amount of sensible heat flux and increased that of latent heat flux. These results suggest that sprinkling reclaimed wastewater on water retentive pavement can effectively mitigate the heat island phenomenon.