Central Ray Research Articles

A new chancelloriid from the Emu Bay Shale (Cambrian Stage 4) of South Australia

Chancelloria australilonga sp. nov. is described from the Emu Bay Shale (Cambrian Series 2, Stage 4) of Kangaroo Island, South Australia. The new species has a typical sac-like body, equipped with a meshwork of dozens of distinctive rosette-like sclerites. Each sclerite comprises one central ray and six or seven lateral rays, and is characterized by a pair of remarkably long and subparallel adapical rays. Chancelloria australilonga is one of the few chancelloriid species preserved with an apical orifice with an obvious peripheral tuft. The tuft consists of a series of single-rayed sclerites with inflated bases. The preservation of the specimens, coupled with sedimentological information and their general rarity in the Emu Bay Shale, suggests short-distance transport and subsequent deposition in a nearshore, low-oxygen preservational trap. Additionally, the known distribution of chancelloriids in the well-documented Konservat-Lagerstätten representing a variety of sedimentary environments, indicates that chancelloriids, especially the genus Chancelloria, were likely adapted to an extensive range of habitats.http://zoobank.org/urn:lsid:zoobank.org:pub:E46167B4-186A-4521-B3D7-DC3F48F72A30

Deletion 7q21.2-q22.1 in a case with split hand-split foot malformation, sensorineural hearing loss and intellectual disability: Phenotype subtypes and the correlation with genotypes

The split hand/split foot malformation (SHFM) or ectrodactyly is a rare congenital heterogeneous limb developmental disorder with at least 6 associated loci. It is characterized by absence of central rays of hands and feet and fusion of remaining digits. It can present as an isolated malformation or in combination with additional anomalies (non-syndromic or syndromic ectrodactyly). This is a report of a 4 year old male child with SHFM with facial dysmorphism, profound sensorineural hearing loss, microcephaly and developmental delay associated with a large deletion of 7.242 MB on chromosome 7q21.2-q22.1. This is the region of SHFM1 (OMIM No. 183600) and deletions of varying sizes have been reported. We have reviewed the phenotypes and genotypes of this locus. The deletions with this severe phenotype are large and some of them detected on traditional karyotyping. The cases with submicroscopic deletions are few but show some correlation of genotype with phenotype which will help in counseling the families with prenatally or neonatally detected deletion at this locus.

An optimized space-time Gaussian beam migration method with dynamic parameter control

In the Gaussian beam (GB) method, initial beam parameters are principal factors influencing the accuracy and computational efficiency of seismic depth imaging. Various optimized beam parameter strategies for Gaussian beam migration (GBM) have been proposed to improve imaging quality as well as computational efficiency, while optimized space-time Gaussian beam schemes for seismic migration have still not been fully investigated. In this paper, an optimized space-time Gaussian beam approach with dynamic parameter control for seismic depth imaging is developed. We first provide an expression for dynamic beam parameter by taking in account the effect of velocity field variation on the beam forming. Based on dynamic beam parameters, the new space-time adaptive Gaussian beam generated by an arbitrary source wavelet is obtained, which can adaptively calculate the beam width to make the seismic beam energy better focused in the central ray neighborhood. Then, the forward wavefield is constructed in two-dimensional (2D) acoustic media by space-time adaptive Gaussian beam for the implementation of migration. Adhering to the framework of conventional space-time Gaussian beam method, we perform the up-going ray tracing from subsurface imaging points to the receiver surface to compute the asymptotic Green function for the construction of the backward wavefield. Numerical experiments demonstrate that the new presented approach has a superior accuracy for seismic depth imaging in both shallow and deep regions compared to the conventional space-time Gaussian beam migration scheme.

PENERAPAN PENJAMINAN MUTU RADIOLOGI PADA KENDALI MUTU PERALATAN BUCKY GRID PESAWAT DIGITAL RADIOGRAPHY

The research about grid performance testing in Radiology Installation RA Kartini Jepara have been done using X-ray digital radiography type Multix Select DR. X-ray digital radiography hasn’t been re-tested after acceptance testing in 2016. Based the frequency, it’s often use. The purpose of this study to know the implementation of radiology quality assurance and quality control and to determine the result testing. Research conducted in the examination room in radiology installation RA Kartini Jepara with depth interviews, two radiographers as a respondents. Then, put a Grid Allignment Test Tool in the middle of center beam, with vertical rays. Afterthat, all the holes exposed by a factor using 45 kVp and mAs setting 1 and 5. Then do the processing and measure the optical density using densitometer three times each holes. In the analysis of data from measurement should determine the value of highest density on the 3rd or center hole and getting decreases to the lateral. The result show the quality assurance and quality control aren’t going well because there is none about QA Committe. Density measurement data show, on the first hole has 2,48 and 2,56. On the second hole has 2,66 and 2,74. On the third hole has 2,71 and 2,81. On the fourth hole has 2,69 and 2,72. The fifth hole has 2,71 and 2,78. The first hole show lowest density value and getting decreases to the lateral side. It means bucky is missalignment with central rays.

Evaluation of the Portal Imaging System Performance for an Elekta Precise Linac in Radiotherapy

Introduction: Electronic portal imaging devices (EPIDs) provide two- and three-dimensional planar and volumetric cone beam images to improve the accuracy of radiation treatment delivery. Periodic quality assurance (QA) of EPIDs is essential for dosimetric verification in radiotherapy. In this study, a QA program was implemented to evaluate the function of the EPID to be confident in applying corrections for the uncertainty of patient set-up. Material and Methods: Firstly, the safety features were verified, and the uniformity of EPID response was evaluated using flat panel detector. Additionally, the contrast and spatial resolutions of the EPID were assessed using detail counting of the Los Vegas phantom images by visualization method and measuring the modulation transfer function using edge technique, respectively. Moreover, a combination of smoothing methods was used for optimal use of edge detection algorithm for the noisy portal images. Finally, the location of the central ray on the EPID surface at different gantry angles was determined to evaluate the mechanical stability of the supporting arm. Results: The safety interlocks were found to be functional.The EPID response variation was less than 3% according to the results obtained from the detector. The contrast resolution met the recommended tolerance; however, the visualization method was widely observer-dependent. The value of f50 for spatial resolution was 0.401±0.005 lp/mm for the photon energy of 6 MV. The supporting arm deviation was within ±1 mm. Conclusion: The periodic QA of image guidance system gave confidence to apply the corrections for set-up in clinic.

Driving accommodation using simulated higher-order aberrations

The purpose of accommodation is to minimize blur. Defocus blur is the major source of blurring in the retinal image, but defocus blur itself cannot tell the eye if it is focused too near or too far. When the human eye is shown real blur, accommodation always changes in the correct direction without searching, so the visual system can somehow determine the sign of defocus. Potential signals for the sign include temporal fluctuations of accommodation (e.g., microfluctuations), chromatic aberration, and higher-order aberrations (HOAs). We investigated whether simulated HOAs—specifically, astigmatism and spherical aberration—provide the needed sign information to drive accommodation in the right direction. Measurable astigmatism occurs in most people; its magnitude and axis varies across individuals. The point-spread function (PSF) of a defocused astigmatic eye is elliptical with the major axis in one direction when the object is farther than current focus and that axis rotated by 90deg when the object is nearer. Spherical aberration is also present in nearly all people. It generally causes marginal rays through the pupil to focus in front of the retina when central rays are focused on the retina. Because of this marginal-central difference, spherical aberration creates different PSFs for objects at different depths relative to the eye's current focus. Therefore, astigmatism and spherical aberration can in principle provide sign information to guide accommodation in the correct direction. We investigated whether they really do aid accommodation. We measured observers' aberrations with a Shack-Hartmann wavefront sensor and generated rendered stimuli that simulated either their native astigmatism or spherical aberration for various simulated distances. We found that simulated astigmatism and spherical aberration can indeed drive accommodation in the right direction, but they are less effective than real changes in focal distance. We conclude that these natural aberrations provide useful sign information for accommodation. Meeting abstract presented at VSS 2018

An Evaluation of Image Acquisition Techniques, Radiographic Practice, and Technical Quality in Neonatal Chest Radiography

BackgroundNeonatal chest radiography is a frequently performed diagnostic examination, particularly in preterm infants where anatomical and/or biochemical immaturity impacts on respiratory function. However, the quality of neonatal radiographic images has been criticized internationally and a prevailing concern has been that radiographers (radiologic technologists) fail to appreciate the unique nature of neonatal and infant anatomical proportions. The aim of this study was to undertake a retrospective evaluation of neonatal chest radiography image acquisition techniques against key technical criteria. MethodsOne hundred neonatal chest radiographs, randomly selected from those acquired in 2014, were retrospectively evaluated. Inclusion criteria for radiograph were as follows: anterior-posterior supine; within 30 days of birth; and with all preprocessed collimation boundaries visible. Image evaluation was systematically undertaken using an image assessment tool. To test for statistical significance, Student's t-test, χ2 test, and logistic regression were undertaken. ResultsOnly 47% of the radiographs were considered straight in both upper and lower thoraces. The cranial collimation border extended beyond the upper border of the third cervical vertebra in 30% of cases, and the caudal border extended below the lower border of the first lumbar vertebra in 20% of cases, suggesting high possibility of neonatal overirradiation. Upper thorax rotation was significantly associated with head position (χ2 = 10.907; P < .001) as has been stated in many published textbooks internationally, but arm position had no apparent influence on rotation of the upper thorax (χ2 = 5.1260; P = .275). Birth weight was associated with accurate midline centering of central ray (logistic regression; OR = 1.0005; P = .009; CI, 1.00139–1.000957) with greater accuracy observed in images of neonates with higher birth weight. ConclusionThis study has highlighted areas for neonatal chest radiography improvement. Importantly, the findings bring into question commonly advocated radiographic techniques relating to arm positioning and assessment of rotation while confirming the importance of other technical factors. These findings begin the work toward developing the evidence base to underpin neonatal chest radiograph acquisition, but further prospective work and multicenter/multinational data comparison are required to confirm the findings.

Proposal of a New Dynamic Distraction Device to Treat Complex Periarticular Fractures of the Metacarpophalangeal Joint of Long Finger.

Background: Complex periarticular fractures of the metacarpophalangeal joint (MCPJ) are often challenging to treat. Conservative and operative treatments are often burdened with stiffness, loss of function, and poor clinical outcome. These phenomena could be a direct consequence of long period of immobilization. To promote a short time of immobilization and a quick return to daily activities, it is mandatory to stabilize the fracture maintaining the active range of motion (AROM) of the ray. A simple solution is to reduce the fragments by means of dynamic ligamentotaxis. The authors propose a new dynamic distraction device (DDD) for the MCPJ. Methods: The DDD for the MCPJ was made of Kirschner wires bent and connected to counteract dislocation forces and to allow mobilization of the joint. The DDD was tested on a cadaver model under a simulated load in physiological conditions, and also in metacarpal and proximal phalanx (P1) fracture patterns. The effectiveness of the device was evaluated under fluoroscopy. Results: The data showed that DDD is able to achieve fracture reduction through ligamentotaxis and primary fragments stability and to avoid secondary dislocation during AROM of complex periarticular fractures of the MCPJ. Conclusions: The frame could be an alternative option to treat periarticular fractures of the MCPJ. The DDD implant has several advantages: It is time efficient because assembly and application take only few minutes. Furthermore, it is very versatile; indeed, it can be used in all metacarpal and phalanx bones, even in the central rays.

Band-limited beam propagator and its application to seismic migration

The ray-tracing technique under the high-frequency assumption has been widely used in seismic wave propagation and migration. However, the practical use of conventional ray tracing is limited in complicated media especially when seismic data are band limited. Besides, the ray-tracing method also suffers from shadow zones in complex media. To alleviate these problems, we have developed a band-limited beam propagator and we apply it in seismic wave propagation and migration, which is flexible to implement and can be friendly to extract angle gathers. To derive the band-limited beam propagator, the band-limited ray-tracing method is adopted to compute the central ray of the beam. These rays in the first Fresnel zone are weighted to obtain the band-limited ray based on the assumption of a local plane wave. Then, the band-limited ray is extended to the band-limited beam propagator using the paraxial approximation. Because the beam propagator has a certain beam width perpendicular to the central ray, it has better illumination than the conventional ray-tracing method, and it could partially alleviate the problem of shadow zones. Finally, we use the band-limited beam propagator to develop a band-limited beam migration and analyze the angle gathers in complicated areas. Numerical examples on synthetic models indicate that the proposed band-limited beam propagator outperforms the conventional ray method in terms of illumination. Its applications in migration determine that it could enhance the imaging quality and produce better angle gathers in a complex area.

Numerical modeling of Gaussian beam propagation and diffraction in inhomogeneous media based on the complex eikonal equation

Gaussian beam is an important complex geometrical optical technology for modeling seismic wave propagation and diffraction in the subsurface with complex geological structure. Current methods for Gaussian beam modeling rely on the dynamic ray tracing and the evanescent wave tracking. However, the dynamic ray tracing method is based on the paraxial ray approximation and the evanescent wave tracking method cannot describe strongly evanescent fields. This leads to inaccuracy of the computed wave fields in the region with a strong inhomogeneous medium. To address this problem, we compute Gaussian beam wave fields using the complex phase by directly solving the complex eikonal equation. In this method, the fast marching method, which is widely used for phase calculation, is combined with Gauss–Newton optimization algorithm to obtain the complex phase at the regular grid points. The main theoretical challenge in combination of this method with Gaussian beam modeling is to address the irregular boundary near the curved central ray. To cope with this challenge, we present the non-uniform finite difference operator and a modified fast marching method. The numerical results confirm the proposed approach.

ANALISA PERBEDAAN INFORMASI ANATOMI THORAKS PADA PROYEKSI ANTERO POSTERIOR (AP) SUPINE ANTARA PENYUDUTAN ARAH SUMBU SINAR 50 CAUDAD DAN VERTIKAL TEGAK LURUS

Backgroud: A finding about different central ray arrangement in the AP supine projection which are using 5° caudad and vertically central ray that occur in the clinical practice hospital turns into the reason of developing this research. A research has been carried out in the clinical practice hospital about thorax x - ray examination with AP supine projection that used 5° caudad and vertically central ray in order to reveal the anatomical information differences between thorax x-ray examination with AP supine projection with the variation of central ray angulation and also to determine the most effective degree of central ray which can demonstrate anatomical information accurately.&#x0D; Methods: The method of this research is quantitative with survey approachment, and qualitative approachment in addition. Data collected by copying 60 thorax x-ray radiograph, admission filling of questioner and interview. The questioner filled by 3 respondents who are radiologist. Those data from the respondents are processed and analysed by using statistical analysis.&#x0D; Results: Interviewing data analysed by data reduction, data presentation, drawing of conclusion and verification. Based on the result of the SPSS statistical Mann-Whitney analysis test, it has been revealed that there are differences of anatomical information between thorax x -ray examination with AP supine projection which are using 5° caudad and vertically central ray, demonstrated by magnification of clavicle, foreshortening of clavicle, foreshortening of costae’s distance, superposition of 1st-5th costae by clavicle, and superposition between anterior and superior co stae. It has been determined that vertically central ray radiograph can demonstrate anatomical information of thorax x - ray examination with AP supine projection accurately by the highest value of Mann -Whitney mean rank 44,68.

New Analysis Scheme of Flow-Acoustic Coupling for Gas Ultrasonic Flowmeter with Vortex near the Transducer.

Ultrasonic flowmeters with a small or medium diameter are widely used in process industries. The flow field disturbance on acoustic propagation caused by a vortex near the transducer inside the sensor as well as the mechanism and details of flow-acoustic interaction are needed to strengthen research. For that reason, a new hybrid scheme is proposed; the theories of computational fluid dynamics (CFD), wave acoustics, and ray acoustics are used comprehensively by a new step-by-step method. The flow field with a vortex near the transducer, and its influence on sound propagation, receiving, and flowmeter performance are analyzed in depth. It was found that, firstly, the velocity and vortex intensity distribution were asymmetric on the sensor cross-section and acoustic path. Secondly, when passing through the vortex zone, the central ray trajectory was deflected significantly. The sound pressure on the central line of the sound path also changed. Thirdly, the pressure deviation becomes larger with as the flow velocity increases. The deviation was up to 17% for different velocity profiles in a range of 0.6 m/s to 53 m/s. Lastly, in comparison to the theoretical value, the relative deviation of the instrument coefficient for the velocity profile with a vortex near the transducer reached up to −17%. In addition, the rationality of the simulation was proved by experiments.

Functional Benefits of Conserving the First Toe in Amputations of Multiple Central and Lateral Rays

Functional Benefits of Conserving the First Toe in Amputations of Multiple Central and Lateral Rays

2D isotropic elastic Gaussian-beam migration for common-shot multicomponent records

Gaussian-beam migration (GBM) is flexible and adaptable for imaging geologically complicated areas. It avoids some limitations, such as amplitude singularity in caustic zones and an inability to image multiple arrivals, of traditional ray-based migration approaches. Previous studies on GBM mainly focused on acoustic media. We have developed a 2D isotropic elastic GBM scheme for common-shot multicomponent records. Our method extrapolates P- and S-mode wavefields simultaneously using the Kirchhoff-Helmholtz integral solution of the isotropic elastodynamic equation. We separate the extrapolated wavefields into compressional and shear modes using the Helmholtz decomposition, and we then implement a modified dot-product imaging condition. This approach enables us to produce clear PP-images and avoid polarity reversal issues for PS-images. In addition, based on the theory of wavefield approximation in the effective vicinity of central rays, we derive a formula to compute the propagation angles of paraxial rays, which can be used to extract angle-domain common-image gathers.

The use of virtual reality simulation to improve technical skill in the undergraduate medical imaging student

ABSTRACTIn recent years, simulation has increasingly underpinned the acquisition of pre-clinical skills by undergraduate medical imaging (diagnostic radiography) students. This project aimed to evaluate the impact of an innovative virtual reality (VR) learning environment on the development of technical proficiency by students. The study assessed the technical skills of first year medical imaging students. The learning experience by each student was either via traditional laboratory-based simulation or VR simulation, for two specified anatomical protocols. Following the learning experience, the students performed role-plays and were assessed on their technical proficiency. The type of learning environment, laboratory-based or VR simulation, was recorded for each radiographic procedure, as well as demographic data. Data demonstrated an improved total role-play skill score for those students trained using VR software simulation compared with the total role-play skills score traditional laboratory simulation. Demographic multivariable analysis demonstrated no statistically significant association of age, gender, gaming skills/activity with the outcome. The novel medical imaging VR simulation learning tool facilitated technical skill acquisition, equal to, or slightly better than traditional laboratory training. Ongoing data collection will evaluate the impact this VR software has on the undergraduate medical imaging student.Abbreviations: QUT: queensland university of technology; VR: virtual reality; SLE: simulated learning environment; PA: posterio-anterior; DP: dorsi-plantar; CP: central point; CR: central ray; SID: source image distance; HWA: health workforce Australia

Loading pattern of postoperative hallux valgus feet with and without transfer metatarsalgia: a case control study

BackgroundPostoperative transfer metatarsalgia is a common complication after hallux valgus surgeries. Shortening of the first metatarsal is traditionally thought to be the primary cause of it. However, we speculate the abnormal loading pattern during gait is the real reason. This study is to determine specific differences in the loading patterns between reconstructive hallux valgus (HV) feet with and without postoperative transfer metatarsalgia, so as to find risky loading characteristics of this complication.MethodsThirty feet with postoperative transfer metatarsalgia were recruited as pain group, while another 30 postoperative feet without pain as controls. All participants were asked to walk barefoot at self-selected speed through a plantar force measuring plate (Rs-Scan Inc.) for three times. Certain plantar load variables were recorded or calculated, and their differences between two groups were compared.ResultsFor pain group, the maximum plantar force and force time integral of the first metatarsal decrease significantly; the force time integral of the central rays (second plus third metatarsal) does not significantly differ with that in the controls, but their cumulative load percentage to the whole foot is higher. In pain group, the time point when central rays reached their peak force during the push-off is significantly later than that in controls. And the regional instant load percentage at this moment presented significantly higher for central rays, while significantly lower for the first metatarsal and the hallux compared to the controls.ConclusionsFor hallux valgus feet with postoperative metatarsalgia, the load function of the first metatarsal is obviously impaired. But for central rays, indicative difference is not reflected in either peak or cumulative load during the gait cycle, but in the instant load distribution when central rays reach their peak load. So we can conclude that whether the remaining regions can adequately share certain load during walking, especially around the time metatarsalgia often occurs, plays an unnegligible role. So surgeons should pay more attention to reconstruct a foot where load can be evenly distributed.

The effect of the relativistic transformation law of angles on laser ranging of satellites moving in circular orbits equipped with a single retroreflector

It is shown that due to the relativistic transformation law of angles, a laser pulse reflected from a moving retroreflector propagates not strictly back, but at a small angle to the direction of the laser station. For this reason, the ray located on the periphery of a pulse reaches the receiving telescope of the laser station instead of the central ray of a pulse. As a result, the flux of electromagnetic energy received by the laser station is certainly less than the flux of energy in the vicinity of the central ray. The energy flux attenuation coefficient is assessed on the basis of numerical analysis. It is shown that if the receiving telescope is separated from the laser station in order to be mobile and is moving along the Earth’s surface so that the center of each spot formed by a pulse of the reflected light hits the telescope, then the electromagnetic energy flux during laser probing of the satellite will be higher by more than 100 times in comparison with the energy flux received by the stationary telescope of the laser station. From our study it follows that the maximum speed of motion of the centers of spots on the Earth’s surface does not exceed 8 km/h.

Velocity-model estimation with NIP-wave tomography inversion – A real data example

The common-reflection-surface (CRS) stack in addition to high signal-to-noise ratio stacked sections creates the curvature and local dip of a reflector. With this information, so-called kinematic wavefield attributes, it is possible to obtain a subsurface velocity model for laterally inhomogeneous media using normal-incidence-point (NIP) wave inversion. The result of CRS provides some location points on the stacked section as input for the inversion. In each iteration, dynamic ray tracing is applied along the central ray according to an input data point. With this technique, the parameter needed for forward modeling will be obtained. By updating the velocity model and minimizing the misfit between input data and the forward model parameter, it is possible to achieve a final velocity model consistent with input data. In this paper, we applied the CRS method on complex structure in the northeast of Iran, and then we performed the NIP-wave tomography inversion on this data set by means of CRS attributes. The result clearly shows the ability of NIP-wave tomography in velocity-model inversion.

Gobiesox lanceolatus, a new species of clingfish (Teleostei: Gobiesocidae) from Los Frailes submarine canyon, Gulf of California, Mexico.

Gobiesox lanceolatus is described from a single specimen collected from 300 meters depth in the Los Frailes submarine canyon in the southwestern Gulf of California. The "Canyon Clingfish" is unique within Gobiesox in having a lanceolate caudal fin, with the central rays longer than those above and below them. It is also distinguished by 14 dorsal-fin rays (first tiny and unsegmented), 11 anal-fin rays, 28 pectoral-fin rays, anus slightly closer to anal-fin origin than to posterior margin of pelvic disc, and dorsal-fin origin in front of vertical from anus. It is most similar to Gobiesox eugrammus, known from Isla Guadelupe, the coast of outer Baja California and southern California. This is the deepest record for a species of Gobiesox and only four other species of clingfishes are known from greater depths.

Introduction of a novel ultrahigh sensitivity collimator for brain SPECT imaging.

Noise levels of brain SPECT images are highest in central regions, due to preferential attenuation of photons emitted from deep structures. To address this problem, the authors have designed a novel collimator for brain SPECT imaging that yields greatly increased sensitivity near the center of the brain without loss of resolution. This hybrid collimator consisted of ultrashort cone-beam holes in the central regions and slant-holes in the periphery (USCB). We evaluated this collimator for quantitative brain imaging tasks. Owing to the uniqueness of the USCB collimation, the hole pattern required substantial variations in collimator parameters. To utilize the lead-casting technique, the authors designed two supporting plates to position about 37 000 hexagonal, slightly tapered pins. The holes in the supporting plates were modeled to yield the desired focal length, hole length, and septal thickness. To determine the properties of the manufactured collimator and to compute the system matrix, the authors prepared an array of point sources that covered the entire detector area. Each point source contained 32 μCi of Tc-99m at the first scan time. The array was imaged for 5 min at each of the 64 shifted locations to yield a 2-mm sampling distance, and hole parameters were calculated. The sensitivity was also measured using a point source placed along the central ray at several distances from the collimator face. High-count projection data from a five-compartment brain phantom were acquired with the three collimators on a dual-head SPECT/CT system. The authors calculated Cramer-Rao bounds on the precision of estimates of striatal and background activity concentration. In order to assess the new collimation system to detect changes in striatal activity, the authors evaluated the precision of measuring a 5% decrease in right putamen activity. The authors also reconstructed images of projection data obtained by summing data from the individual phantom compartments. The sensitivity of the novel cone-beam collimator varied with distance from the detector face; it was higher than that of the fan-beam collimator by factors ranging from 2.7 to 162. Examination of the projections of the point sources revealed that only a few holes were distorted or partially blocked, indicating that the intensive manual fabrication process was very successful. Better reconstructed phantom images were obtained from the USCB+FAN collimator pair than from either LEHR or FAN collimation. For the left caudate, located near the center of the brain, the detected counts were 9.8 (8.3) times higher for UCSB compared with LEHR (FAN), averaged over 60 views. The task-specific SNR for detecting a 5% decrease in putamen uptake was 7.4 for USCB and 3.2 for LEHR. The authors have designed and manufactured a novel collimator for brain SPECT imaging. The sensitivity is much higher than that of a fan-beam collimator. Because of differences between the manufactured collimator and its design, reconstruction of the data requires a measured system matrix. The authors have demonstrated the potential of USCB collimation for improved precision in estimating striatal uptake. The novel collimator may be useful for early detection of Parkinson's disease, and for monitoring therapy response and disease progression.