Brief histories of medical physics in Asia-Oceania.

The history of medical physics in Asia-Oceania goes back to the late nineteenth century when X-ray imaging was introduced, although medical physicists were not appointed until much later. Medical physics developed very quickly in some countries, but in others the socio-economic situation as such prevented it being established for many years. In others, the political situation and war has impeded its development. In many countries their medical physics history has not been well recorded and there is a danger that it will be lost to future generations. In this paper, brief histories of the development of medical physics in most countries in Asia-Oceania are presented by a large number of authors to serve as a record. The histories are necessarily brief; otherwise the paper would quickly turn into a book of hundreds of pages. The emphasis in each history as recorded here varies as the focus and culture of the countries as well as the length of their histories varies considerably.

SU-E-T-509: Photon Spectrum Modeling of Flattening Filter Free (FFF) Beam and the Optimization of Model Parameters.

PURPOSE: To determine the distribution of photon spectrum on flattening filter free (FFF) beams, novel and fast optimization methods that were applicable on a convolution/superposition dose calculation algorithm were implemented. METHODS: Two-step optimization method was designed to model the virtual photon spectrums for FFF beams. At first, simple functional form of photon spectrums proposed by E. S. M. Ali was modified and used to make rough shapes of photon spectrum. The distributions of photon spectrums were defined at various field sizes (FSs) to consider the changes of the contribution for scattered photons. Percent depth doses (PDDs) at various FSs were used, and collapsed cone convolution (CCC) algorithm was used to calculate PDDs by considering cone-shaped photon fluence in fields. At next, an arbitrary functional form of photon spectrums where the values of photon intensity itself were free parameters was designed. Line search method was used for optimization and gradient terms at each free parameter were derived from CCC algorithm to enhance the speed of iterations. RESULTS: The mean energies of the optimized spectrums were decreased from 1.40 to 1.21 MeV for 6 MV FFF beams and from 2.45 to 1.27 MeV for 10MV FFF beams as FSs were increased from 3×3 to 40×40 cm2 because of the contributions of scattered photons. The shape of the spectrums were not greatly changed with field sizes, but root mean squared differences (RMSDs) between the measured PDDs and the calculated PDDs using optimized spectrums were increased upto 0.87% as the FSs were decreased to 3×3 cm2 . CONCLUSIONS: Developed method for spectrum modeling showed good agreements when the PDDs were calculated with the optimized results. Suggested method is proper to the radiation treatment planning systems because it only requires measured PDDs, and based on the analytic dose calculation algorithm. This work was supported by the National Research Foundation of Korea(NRFK)⌉ grant funded by the Korean government (MEST)⌉ (Grant No. K20901000001-09E0100-00110⌉), Varian Medical Systems, NCI Grant No.1R01 CA98523⌉, and NSF Grant No. 0854492⌉.

SU-E-T-537: Photon Beam Modeling and Verification of Collapsed Cone Convolution Algorithm for Dose Calculation in a Radiation Treatment Planning System.

PURPOSE: The aim of this study is to evaluate the accuracy the collapsed cone convolution (CCC) algorithm for dose calculation in a radiation treatment planning system (TPS). METHODS: We modeled various photon beams for various setup conditions in a radiation treatment planning system (CorePLANTM, Seoul C&J, Korea). The beam models were generated at various set-up conditions such as open beam or wedged beam, 6 MV or 15 MV beam and field sizes from 4×4 cm2 to 40 × 40 cm2 . Each beam model was optimized by spectrum modeling from measured percent depth dose (PDD) data, dose profile modeling from a measured profile at a specific depth (10 cm) data. Dose calculation was performed using conventional CCC algorithm. All measured data were acquired from a Clinac 21EX (Varian Medical System, Palo Alto, CA, USA) linear accelerator with the setting of SSD = 100 cm. All calculated PDD and dose profiles at various depths from generated beam models were compared to the measured data. RESULTS: Calculated dose data from each beam model showed good agreements within 2% of difference to the measured PDD and within 3% dose profiles at various depths. Some regions such as penumbra region at 20 × 20 cm2 field size and horn region at wedge field showed dose discrepancies over 3%. The results of PDD at all situations showed well agreement with measured data under the 10×10 cm2 field size. For wedged cases, however, under the 5 cm depths, some inconsistency at penumbra region were appeared. CONCLUSIONS: In this study, we verified the accuracy of CCC algorithm in the TPS. Calculated results by our implemented algorithm was well satisfied with measured dose at small field size (〈20 7 times; 20 cm2 ). Our next study will perform to compensate theses inconsistencies.

TU-G-BRB-03: Iterative Optimization of Normalized Transmission Maps for IMRT Using Arbitrary Beam Profiles.

PURPOSE: Newly available flattening filter free (FFF) beam increases the dose rate by 3∼6 times at the central axis. In reality, even flattening filtered beam is not perfectly flat. In addition, the beam profiles across different fields may not have the same amplitude. The existing inverse planning formalism based on the total-variation of intensity (or fluence) map cannot consider these properties of beam profiles. The purpose of this work is to develop a novel dose optimization scheme with incorporation of the inherent beam profiles to maximally utilize the efficacy of arbitrary beam profiles while preserving the convexity of the optimization problem. METHODS: To increase the accuracy of the problem formalism, we decompose the fluence map as an elementwise multiplication of the inherent beam profile and a normalized transmission map (NTM). Instead of attempting to optimize the fluence maps directly, we optimize the NTMs and beam profiles separately. A least-squares problem constrained by total-variation of NTMs is developed to derive the optimal fluence maps that balances the dose conformality and FFF beam delivery efficiency. With the resultant NTMs, we find beam profiles to renormalized NTMs. The proposed method iteratively optimizes and renormalizes NTMs in a closed loop manner. RESULTS: The advantage of the proposed method is demonstrated by using a head-neck case with flat beam profiles and a prostate case with non-flat beam profiles. The obtained NTMs achieve more conformal dose distribution while preserving piecewise constancy compared to the existing solution. CONCLUSIONS: The proposed formalism has two major advantages over the conventional inverse planning schemes: (1) it provides a unified framework for inverse planning with beams of arbitrary fluence profiles, including treatment with beams of mixed fluence profiles; (2) the use of total-variation constraints on NTMs allows us to optimally balance the dose confromality and deliverability for a given beam configuration. This project was supported in part by grants from the National Science Foundation (0854492), National Cancer Institute (1R01 CA104205), and Leading Foreign Research Institute Recruitment Program by the Korean Ministry of Education, Science and Technology (K20901000001-09E0100-00110). To the authors' best knowledgement, there is no conflict interest.

SU-E-J-137: A Theoretical Model for the Analysis of Residual Motion Artifacts in 4D CT Scans.

PURPOSE: The purpose of this study was to analysis the residual motion artifact in 4D-CT scan using a simple one-dimension theoretical model. METHODS: In order to evaluate the target displacement at each phase image, We used phantom (Dynamic Thorax Phantom, CIRS, Norfolk, VA) which could control programmable regular 1D sine motion and belt type respiratory monitoring system. 2cm diameter spherical target was inserted in the phantom and then we set-up regular 1D sine motion and adjusted three level of amplitude (10, 20, 30 mm) with fixed period (4s). Four dimensional (4D) CT images were acquired by CT scanner (Sensation Open, Siemens Medical Systems, Forchheim, Germany) with a slice thickness of 1.5 mm and 0.1 pitch in helical mode. Respiratory monitoring system (AZ-733V, Anzai MEDICAL) was placed on the abdominal surface of phantom, and the respiratory signal was acquired. CorePLAN (RTP, SC&J) software was used to acquire static target diameter and each ten phase diameters. RESULTS: The displacements (?S) peak at the 20∼30% or 70∼80% phases, and are minimized at the 50% phase. This is because the target velocity is minimum at 50% phase and maximum at 30 and 70% phases; hence, the large image blur. The measured diameters of target are compared to the simulation results and we observed similar trends of target diameter change. CONCLUSIONS: In this study, we presented simple one-dimensional model to analyze the residual motion artifact in 4D-CT scan. The model was used to explain the effect of residual motion on each phase target displacement and also shown that residual motion artifact was affected that the target velocity at each phase. Lastly based on this model, we developed simulation program and acquired similar results of target displacement compared with measured data. This research was supported by Leading Foreign Re-search Institute Recruitment Program through the National Research Foundation of Korea (NFR) (Grant No. K20901000001-09E0100-00110,) and the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R and D Programs (No.20110006324) funded by the Ministry of Education, Science and Technol-ogy(MEST).

SU-E-J-211: Development of Respiratory Training System Using Individual Characteristic Guiding Waveform.

PURPOSE: The purpose of this study is to develop the respiratory training system using individual characteristic guiding waveform to reduce the impact of respiratory motion that causes artifact in radiation therapy. METHODS: Respiratory training system was developed by LabView (National Instruments, version 8.6). The real-time respiratory signals were acquired using in-house developed belt type sensor and more user-comfortable HMD was used for visual guiding (Vuzix, Wrap 920). The respiratory training program consists of three main components. It is (1) respiratory signal reading and peak detection program (2) individual characteristic guiding waveform generation program (3) respiratory signals acquisition and visual guiding program. In order to evaluate the feasibility of in-house developed respiratory training system, 5 volunteers were included and their respiratory signals were acquired using the in-house developed belt-type sensor. Respiratory training system needs 10 free breathing cycles of each volunteer to make individual characteristic guiding waveform based on Fourier series and it guides patient's next breathing. For each volunteer, free breathing and guided breathing which uses individual characteristic guiding waveform were performed to acquire the respiratory cycles for 3 min. The root mean square error (RMSE) was computed to analyze improvement of respiratory regularity in period and displacement. RESULTS: It was found that respiratory regularity was improved by using respiratory training system. RMSE of guided breathing decreased up to 40% in displacement and 76% in period compared with free breathing. The average of RMSE was decreases from 0.012V to 0.008V in displacement and from 0.432 sec to 0.192 sec in period. CONCLUSIONS: In conclusion, since the guiding waveform was easy to follow for the volunteers, The respiratory regularity was significantly improved by using in-house developed respiratory training system. So it would be helpful to improve accuracy and efficiency during 4D-RT, 4D-CT.

SU-E-J-198: Bioluminescence Monitoring of Metastatic Breast Cancer: Quantitative Assessment of Radiation Treatment Effects and Tracking of Tumor Cells.

PURPOSE: To evaluate radiation treatment effects on mammary carcinoma cells, quantitative photon radiance were monitored to track light-emitting cancer cells and metastasis using in vivo bioluminescence imaging. METHODS: Eight female BALB/c mice aged 8 weeks were orthotopically injected with 5×104/cc 4T1 tumor cells into the abdominal mammary gland. The firefly luciferase-based bioluminescence images were acquired every 2-3 days for 1 month. Bioluminescent intensity was analyzed in average surface radiance (photons/sec/cm2 /sr) taken in 3-dimensional bioluminescence tomography (BLT). After 1 week, single-radiation dose of 20 Gy was delivered by orthovoltage X-rays. Variation of detected bioluminescence signals emitted from molecular cancer cells was depicted on BLT images. To delineate tumor volumes according to bioluminescence intensity on anatomical images for radiation therapy, BLT images were registered with the micro computed tomography (CT) images using surface-constrained warping. RESULTS: Multispectral BLT images elaborated on early detection of cancer cells, characteristics of tumor growth, and metastasis for more accurate determination of internal bioluminescent sources. The radiation-treated mice having only primary tumor volumes showed 67% decrease in bioluminescent signals, while the mice with metastatic cancer cells suggested 88% reduction, as compared to the control group. Registration of BLT with CT images guided molecular cancer cells on anatomical coordinates. CONCLUSIONS: The BLT imaging was a useful tool to localize cancer cells and to quantify radiation response. Application of BLT led to more accurate definition of tumor volumes including molecular probe-based microscopic cancer cells. Monitoring of bioluminescence signals enables to diagnose real-time metastatic behavior of cancer cells and determine optimal radiation treatment strategies adapted to tumor characteristics.

SU-E-T-566: A Dosimetric Comparison of Partial Breast Irradiation Technique Depending on the Tumor Locations in Patient's Breast.

PURPOSE: The present study was designed to suggest the optimal treatment modalities among 3D-conformal radiation therapy, electron beam therapy and helical-tomotherapy depending on classified tumor locations in patient's breast using Partial Breast Irradiation (PBI) technique. METHODS: The CT dataset of six patients who had received lumpectomy treatments was used to treatment plans of 3D-conformal radiation therapy, electron beam therapy and helical-tomotherapy. The tumor locations were classified into eight sections according to the quadrants of the breast and to the superficial or deep positions. To evaluate the dosimetric results from the suggested treatment modalities and tumor locations, conformation number, radical dose-homogeneity and delivered doses to normal tissue were calculated. Kruskall-Wallis, Mann-Whitney U and Bonferroni method was used as statistical analysis. RESULTS: Helical-tomotherapy is not recommendable method in PBI technique because the dosimetric results from radical dose- homogeneity and the delivered dose to organ at risk showed worse results at all tumor locations compared to other modalities. For helical-tomotherapy, the volume of heart received more than 2.5 Gy was maximized more than 90% of total heart volume at all tumor locations. Electron beam therapy showed good sparing effect to normal tissues and acceptable target coverage in Lower Inner Quadrant-Superficial (LIQ-S) and Lower Inner Quadrant- Deep (LIQ-D) cases. CONCLUSIONS: Electron beam therapy could be recommendable method to treat tumor at LIQ-S, LIQ-D locations rather than 3D-conformal radiation therapy, helical-tomotherapy at PBI technique because electron beam therapy is considered to provide the acceptable target coverage and the greatly lower dose to surrounding tissue.

SU-E-T-609: Improving the Efficiency of VMAT Plan Optimization by Using Sparse Decomposition Method.

PURPOSE: Volumetric modulated arc therapy (VMAT) is capable of delivering highly conformable dose distribution efficiently. Its planning is, however, more computationally intensive and requires a huge amount of memory space for optimization. We present an efficient sparse decomposition method for VMAT plan optimization. METHODS: A quadratic objective function with volumetric constraints is expressed as a function of the aperture shapes and weights of the incident beams. The algorithm generates a sequence of iterates to solve the optimization problem. Each step of iteratively reweighed method is to be updated by solving the subproblem involving a quadratic (L2) term and a sparsity-inducing regulation (L1) term. Through the sparse decomposition techniques of the given problem, the deliverable apertures are directly generated. The shape of each aperture is iteratively rectified to be a sequencing of arc using the manufacture constraints. An initial arc spacing of 8 degree creates 45 beams directions for a single arc, 360 degree. The angular separation is equispaced every 2 degree over the end of optimization cycle. The optimization is implemented for a Varian TrueBeamTM STX linac beams with and without flattening filters available. Three clinical cases, head and neck, lung, and prostate, have been studied for the purpose of evaluating the planning efficiency and quality of the plans. RESULTS: The target dose coverage and critical structure sparing of VMAT plan are comparable to those of IMRT plans. The VMAT plan delivers lower doses to other OARs while keeping the similar target dose coverage to IMRT plan. The VMAT plan optimizations takes less than 3 minutes on average of the cases indicating great efficiency compared to existing methods. CONCLUSIONS: The results demonstrate that the proposed method provides competent computational efficiency for optimizing VMAT plan. The method substantially improves the speed and accuracy of VMAT plan optimization and makes future on-treatment adaptive re-planning possible.

SU-E-T-402: Coordinate Transformation after Stereotactic Frame Reapplication in Gamma Knife Radiosurgery.

PURPOSE: In Gamma Knife (GK) radiosurgery, the occurrence of reapplying the stereotactic frame due to collision with the collimator leads to re- examination and re-planning. For the treatment of vascular lesions, it is a burden not only to physicians but also to patients to get invasive angiography procedure again. To avoid undergoing second angiography examination, and reduce re-planning time, a mathematical coordinate transformation method using the stereotactic images has been developed. METHODS: The MR or CT images of a patient brain before and after frame reapplication can be correlated with each other using the Affine transformation. The transformation parameters which minimize the RMS error of the original and transformed coordinates between the images were determined using a genetic algorithm. Three CT image studies of skull phantom were used for the verification of the algorithm. Moreover, five MR image studies of patients who underwent more than one GK procedure were used for the clinical evaluation. The coordinates under the original treatment plan were converted to new coordinates using the transformation matrix, and their dosimetric outcomes were compared. RESULTS: The RMS error in the coordinate transformation of skull phantom and clinical images was 0.3 mm and 0.6 mm, respectively. For total 9 treatment lesions of 0.2 ∼14.1 cc, 3% and 11% RMS error in the irradiation time and target coverage were found respectively. The patients with only translational movement during the frame reapplication showed similar plan conversion results with the original plan. Also, deeply-located lesions showed a better RMS error of 3% in the conformity index than superficial lesions close to the skull. CONCLUSIONS: New treatment plans were obtained by applying the coordinate transformation to the original plans after the frame reapplication. The converted plans maintained the quality of the original plans with a little change in dose distribution arising from head rotation. This work was supported by a grant no. 04-2011-0320110130 from the Seoul National University Hospital Research Fund and a National Research Foundation of Korea (NRFK) grant funded by the Korean government (MEST) (Grant No. K20901000001-09E0100-00110).

SU-E-T-296: Optimization of the Energy Selection System with Varying Magnetic Field for Laser-Accelerated Proton Beams.

PURPOSE: Laser-based accelerated proton beams are unsuitable for clinical use because of their broad energy spectra. For this reason, it is essential to employ an energy selection system (ESS). The purpose of this study is to determine optimum parameters of the ESS which uses a varying magnetic field to generate Bragg-peak. METHODS: We simulated an accelerated proton beams using radiation pressure acceleration mechanism with carbon-proton mixture target. The density ratio (n = 6) between the protons and the carbon ions is one of optimization parameters in determining the accelerating mechanisms. The ESS was implemented by the Geant4 Monte Carlo toolkit. In order to optimize the hole size and position of the energy selection collimator, and magnetic field at ESS, these parameters were simulated for acquiring energy and dose distributions by changing each values. RESULTS: The proton energy distributions had a poly-energetic distribution after passing through the ESS. As the magnetic field was increased, the mean energy of the proton beams also was increased. Also as the hole size was increased, the energy bandwidth of proton passed through the ESS was increased. The hole size and position of the energy selection collimator were effectively optimized to 2 cm and 5 cm from the z-axis, respectively. CONCLUSIONS: We simulated laser-accelerated proton beams using ESS for generation of Bragg-peak. Our results suggest that the ESS with magnetic field variation can effectively generate a Bragg-peak suitable for use in proton radiation therapy. Our ESS can be applied to pencil beam scanning proton therapy.

SU-E-T-644: Incorporating High Dose Inhomogeneity into SBRT Treatment Planning.

PURPOSE: By encouraging greater dose inhomogeneity in the PTV, SBRT allows higher doses to be delivered to the target, and thus improves local control and treatment outcome. This work aims to incorporate the high dose inhomogeneity constraint into SBRT treatment planning in safer manner. METHODS: Two approaches are proposed to achieve high dose inhomogeneity: (1) implicitly reduce dose uniformity by increasing the error tolerance for the PTV; (2) explicitly add specific localized information by introducing the structure, located at 5 mm to 1 cm inside the PTV, and prescribe a higher dose. We formulate the inverse planning problem in a total-variation minimization framework to reduce the complexity of the fluence maps. The optimization problem was solved with a fast and efficient first-order method called TFOCS. For validation, 15-beam IMRT plans were generated for a lung SBRT case, where normal tissue constrains are directly taken from the RTOG lung SBRT protocol 0915. The inhomogeneous plans generated from the two approaches were compared with a homogeneous plan in terms of dose distributions. RESULTS: Both inhomogenous plans delivered higher doses to the target compared with the homogenous plan, with a ∼10% increase in max dose. The implicit approach increased the high dose spillage (outside PTV) to 0.52%, leading to more tissue damage. On the other hand, the explicit approach maintained the high dose spillage at a lower level of 0.18%, similar to that of the homogenous plan. Moreover, with local information of the PTV, the explicit approach allocated the hot spots around the center of the PTV, ensuring the safety and effectiveness of SBRT. CONCLUSIONS: The proposed method using specific localized information inside the PTV can safely and effectively deliver high doses to the target and lead to improved local control.

SU-E-T-628: A Cloud Computing Based Multi-Objective Optimization Method for Inverse Treatment Planning.

PURPOSE: Multi-objective (MO) plan optimization entails generation of an enormous number of IMRT or VMAT plans constituting the Pareto surface, which presents a computationally challenging task. The purpose of this work is to overcome the hurdle by developing an efficient MO method using emerging cloud computing platform. METHODS: As a backbone of cloud computing for optimizing inverse treatment planning, Amazon Elastic Compute Cloud with a master node (17.1 GB memory, 2 virtual cores, 420 GB instance storage, 64-bit platform) is used. The master node is able to scale seamlessly a number of working group instances, called workers, based on the user-defined setting account for MO functions in clinical setting. Each worker solved the objective function with an efficient sparse decomposition method. The workers are automatically terminated if there are finished tasks. The optimized plans are archived to the master node to generate the Pareto solution set. Three clinical cases have been planned using the developed MO IMRT and VMAT planning tools to demonstrate the advantages of the proposed method. RESULTS: The target dose coverage and critical structure sparing of plans are comparable obtained using the cloud computing platform are identical to that obtained using desktop PC (Intel Xeon® CPU 2.33GHz, 8GB memory). It is found that the MO planning speeds up the processing of obtaining the Pareto set substantially for both types of plans. The speedup scales approximately linearly with the number of nodes used for computing. With the use of N nodes, the computational time is reduced by the fitting model, 0.2+2.3/N, with r̂2>0.99, on average of the cases making real-time MO planning possible. CONCLUSIONS: A cloud computing infrastructure is developed for MO optimization. The algorithm substantially improves the speed of inverse plan optimization. The platform is valuable for both MO planning and future off- or on-line adaptive re-planning.

SU-E-I-74: White Matter Tract Disintegrate of Frontal and Limbic Regions in Mild Cognitive Impairment with Depression.

PURPOSE: Mild cognitive impairment with depression (MCID) is common and associated with disability and cognitive impairment, with high probability of relapse. Hypothesize that 1) a sign of WM disintegration would be observed in MCID than MCI nondepression (MCIND), especially in frontal and limbic regions and patients with depression would show reduced GM density in the hippocampus, amygdala, anterior gyrus cingulate, and dorsolateral prefrontal cortex (DLPFC) and dorsomedial prefrontal cortex (DMPFC) 2) the abnormalities of long association fiber tracts integrity are correlated with geriatric depression. METHODS: Forty-two subjects (20 nondepressed, 22 depressed) underwent DTI and cognitive assessment. Depression was initially assessed by means of the Korean version of the 30-item Geriatric Depression Scale (K-GDS). All patients scoring 19 or higher on the K-GDS were screened as depressed. An automated tract-based statistical analysis method was used to derive estimates of fractional anisotropy (FA) for each subject. Group effects and correlations with clinical features on DTI parameters were examined. RESULTS: We found cross-sectional differences in WM tract disintegration on posterior cingulum, splenium of corpus callosum, uncinate fasciculus, genu, thalamus, internal and external capsule of limbic in MCID. These results support changes in the structural integrity of neuronal cells in these specific important brain regions constituting a fronto-limbic-cerebellar network during depressive and in particular during the course of depression. The different parts of the frontal lobes have afferent and efferent connections with other neocortical, limbic, and subcortical regions and participate in the limbic-cortico-striatal-pallidal-thalamic circuits. CONCLUSIONS: Findings are suggestive of loss of integrity in WM fiber within frontal, temporal and limbic regions, increasing the evidence that implicates disruptions to the limbic-orbitofrontal networks in the pathogenesis of MCID. These neuroanatomical circuits play an important role in the regulation and modulation of affect and emotion, and contribute to the pathogenesis of late-life depression.

SU-E-I-73: Gray Matter Atrophy and White Matter Tract Abnormalities by Voxel Wise Correlation Analysis in Patients with Alzheimer's Disease.

PURPOSE: We evaluated the relationship between white matter (WM) tract disintegration and gray matter (GM) atrophy in patients with Alzheimer's disease (AD), mild cognitive impairment (MCI) and controls, using diffusion tensor imaging (DTI) and an optimized voxel-based analysis. METHODS: Two hundred thirty one individuals (61 controls, 116 MCI and 54 AD) were included. Voxel-based WM tract statistics was used to obtain whole-brain maps of WM bundles for FA. Voxel-based morphometry (VBM) was conducted to detect regions of gray matter (GM) atrophy in the AD, MCI group relative to the control group. FA maps were processed to make voxel-wise comparison of tract based analysis in whole brain between each the two groups. The relationship between locations of abnormalities in the WM and GM were examined. RESULTS: Patients with AD showed significant GM atrophy in posterior cingulate gyrus (BA31, 32) to the precuneus, the middle temporal lobe (BA19), the superior frontal (BA9) to the anterior cingulate (BA 32), the medial frontal lobe (BA 11, BA25), the hippocampus, the parahippocampal gyrus (BA30/34) and the insula, and WM tract disintegrity of the uncinate fasciculus, posterior cingulate fasciculus and fornix compared with the control and MCI groups. These abnormalities in the AD group were caused by either structural changes in GM atrophy or neural dysfunction due to functional disconnections in the WM tract. CONCLUSIONS: The GM atrophy resulting from WM tract disintegration or GM atrophy itself may be the first step in the AD process, resulting in anatomically congruent correlations between WM disintegration and regional GM atrophy. Using tract based spatial statistics and voxel based analysis, both of which are useful in investigating GM and WM changes in individuals with neurodegenerative disorders.

Effects of age and equine follicle-stimulating hormone (eFSH) on collection and viability of equine oocytes assessed by morphology and developmental competency after intracytoplasmic sperm injection (ICSI).

Young (4 to 9 yr) and old (>or=20 yr) mares were treated with equine follicle-stimulating hormone (eFSH), and oocytes were collected for intracytoplasmic sperm injections (ICSI). Objectives were to compare: (1) number, morphology and developmental potential of oocytes collected from young v. old mares from cycles with or without exogenous eFSH and (2) oocyte morphology parameters with developmental competence. Oocytes were collected from preovulatory follicles 20 to 24 h after administration of recombinant equine LH and imaged before ICSI for morphological measurements. After ICSI, embryo development was assessed, and late morulae or blastocysts were transferred into recipients' uteri. Cycles with eFSH treatment resulted in more follicles (1.8 v. 1.2) and more recovered oocytes (1.1 v. 0.8) than those without eFSH. Age and eFSH treatment did not effect cleavage, blastocyst and pregnancy rates. Treatment with eFSH had no effect on oocyte morphology, but age-associated changes were observed. In old mares, zona pellucidae (ZP) were thinner than in young mares, and perivitelline space and inner ZP volume (central cavity within the ZP) were larger and associated with oocytes that failed to develop. These results suggest that administration of eFSH can increase the number of oocytes collected per cycle. Oocyte morphology differed with age and was associated with developmental competence.

Vitrification of early-stage bovine and equine embryos.

The objectives of this study were to: (1) determine an optimal method and stage of development for vitrification of bovine zygotes or early embryos; and (2) use the optimal procedure for bovine embryos to establish equine pregnancies after vitrification and warming of early embryos. Initially, bovine embryos produced by in-vitro fertilization (IVF) were frozen and vitrified in 0.25mL straws with minimal success. A subsequent experiment was done using two vitrification methods and super open pulled straws (OPS) with 1- or 8-cell bovine embryos. In Method 1 (EG-O), embryos were exposed to 1.5M ethylene glycol (EG) for 5min, 7M ethylene glycol and 0.6M galactose for 30s, loaded in an OPS, and plunged into liquid nitrogen. In Method 2 (EG-DMSO), embryos were exposed to 1.1M ethylene glycol and 1.1M dimethyl sulfoxide (DMSO) for 3min, 2.5M ethylene glycol, 2.5M DMSO and 0.5M galactose for 30s, and loaded and plunged as for EG-O. Cryoprotectants were removed after warming in three steps. One- and eight-cell bovine embryos were cultured for 7 and 4.5 d, respectively, after warming, and control embryos were cultured without vitrification. Cleavage rates of 1-cell embryos were similar (P>0.05) for vitrified and control embryos, although the blastocyst rates for EG-O and control embryos were similar and higher (P<0.05) than for EG-DMSO. The blastocyst rate of 8-cell embryos was higher (P<0.05) for EG-O than EG-DMSO. Therefore, EG-O was used to cryopreserve equine embryos. Equine oocytes were obtained from preovulatory follicles. After ICSI, injected oocytes were cultured for 1-3 d. Two- to eight-cell embryos were vitrified, warmed and transferred into recipient's oviducts. The pregnancy rate on Day 20 was 62% (5/8) for equine embryos after vitrification and warming. In summary, a successful method was established for vitrification of early-stage bovine embryos, and this method was used to establish equine pregnancies after vitrification and warming of 2- to 8-cell embryos produced by ICSI.

Application of a glass rod detector for the output factor measurement in the CyberKnife.

A radiophotoluminescent glass rod detector has recently become commercially available. We evaluated the feasibility of the commercial glass rod as a new detector for measuring output factors in the CyberKnife. The glass rod detector was irradiated in a water phantom using a holder stand, which was specially designed for this study. The holder was composed of a PMMA tube with an attached vertical bar for the glass rod detector. The measured output factors obtained with the glass rod detector were compared with measurements made with a pinpoint ionization chamber, a diode, and a radiochromic film. The measured relative output factors obtained with the glass rod detector agreed with other detectors within 1.0% for collimator sizes larger than 20mm. However, it was observed that the differences between the output factors measured with the glass rod detector and those obtained with the pinpoint chamber increased rapidly as the collimator size decreased. The relative output factors measured with the diode were consistently higher than those obtained using other detectors for the collimators sizes less than 10mm in diameter. The glass rod detector results were in good agreement with those obtained from the radiochromic EBT film over the entire range of collimator sizes.

Embryo production from superovulated cattle following insemination of sexed sperm.

Two trials were conducted to ascertain fertilization rate, embryo quality and numbers of transferable embryos in superovulated heifers and cows inseminated with sexed sperm. Inseminates contained 2 x 10(6), 10 x 10(6) or 20 x 10(6) total sperm enriched for the X- or Y-chromosome ( approximately 90%) by flow cytometry/cell sorting. Non-sexed inseminates contained 40 x 10(6) total sperm. Donors in each trial were allocated to one of each of the bulls included in that study. Each donor was inseminated with frozen/thawed sperm from the same bull for each treatment in successive courses of superstimulation with twice daily i.m. injections of FSH for 4 d. Heifers and cows were inseminated 12 and 24 h after visually observed standing estrus in Trial 1. In Trial 2, a single timed inseminate was used 70-72 h following PGF(2alpha). Ova/embryos were collected non-surgically 7-7.5 d after insemination. In both trials, fewer ova were fertilized with sexed versus non-sexed treatments and with 2 x 10(6) sexed sperm compared to higher doses (P < 0.05). However, insemination of 20 x 10(6) total sexed sperm of >or=90% purity resulted in similar numbers of transferable embryos of the desired sex compared to that for non-sexed sperm.