Uncorrected Error Research Articles

From 2D to 3D

Mid-air text entry on virtual keyboards suffers from the lack of tactile feedback, which brings challenges to both tap detection and input prediction. In this paper, we explored the feasibility of single-finger typing on virtual QWERTY keyboards in mid-air. We first conducted a study to examine users' 3D typing behavior on different sizes of virtual keyboards. Results showed that the participants perceived the vertical projection of the lowest point on the keyboard during a tap as the target location and inferring taps based on the intersection between the finger and the keyboard was not applicable. Aiming at this challenge, we derived a novel input prediction algorithm that took the uncertainty in tap detection into a calculation as probability, and performed probabilistic decoding that could tolerate false detection. We analyzed the performance of the algorithm through a full-factorial simulation. Results showed that the SVM-based probabilistic touch detection together with a 2D elastic probabilistic decoding algorithm (elasticity = 2) could achieve the optimal top-5 accuracy of 94.2%. In the evaluation user study, the participants reached a single-finger typing speed of 26.1 WPM with 3.2% uncorrected word-level error rate, which was significantly better than both tap-based and gesture-based baseline techniques. Also, the proposed technique received the highest preference score from the users, proving its usability in real text entry tasks.

Contact on-machine measurement probe error correction method for optical aspheric surface ultraprecision machining

Optical aspheric ultraprecision machining requires nanometer-scale on-machine measurement (OMM) techniques, and small probe errors in the contact OMM process can seriously affect the OMM accuracy, thereby reducing machining accuracy. Thus, a master ball-based probe radius error and probe profile error correction method is proposed to analyze the effects of probe radius error and probe profile error on OMM results while ensuring accurate probe alignment to establish an identification and correction model for probe radius error and probe profile error. OMM probe error correction measurement and error compensation machining experiments were conducted to verify the effectiveness of the probe error correction method. After the probe profile error correction measurement, the probe measurement error was changed from 0.436 μm to 0.023 μm. Compared with the uncorrected probe error and the probe radius error correction compensation machining results, the accuracy of the compensation machining after the probe profile error correction compensation was improved by 43 % and 41 %, respectively. Results show that this OMM system probe error correction method is effective in improving OMM accuracy.

An Efficient Self-Healing Architecture for Improving the RAS Characteristics of RISC-V Server and Its Quantitative Evaluation Method

This letter proposes a self-healing called automatic monitoring architecture (AMA), which can help RISC-V server self-heal from hardware errors. AMA reduces redundant error classification, and only monitors hardware devices that have a relatively large proportion of errors in RISC-V server, thereby reducing the resource consumption of AMA on the basis of ensuring performance. In addition, AMA uses the Correctable-error Dynamic Threshold technology to further reduce the probability of serious uncorrectable hardware errors. Compared with an RISC-V server without a self-healing system, this architecture consumes very few hardware resources, reducing server downtime by about 80% each year. Compared with other self-healing architectures, such as Intel’s machine check architecture, AMA can reduce server downtime by an additional 5% per year. Therefore, AMA is highly efficient with little resource consumption.

Bioimpedance as a measure of fluids in patients with septic shock. A prospective observational study.

Septic shock is often treated with aggressive fluid resuscitation leading to profound fluid overload. The assessment of fluid status relies on suboptimal measures making treatment difficult. Bioelectrical impedance analysis is an alternative but the validity is unclear. The aim of this study was to determine the validity of bioelectrical impedance analysis for fluid measures in patients with septic shock. Single-center, prospective observational cohort study. We included adult ICU patients with septic shock. We evaluated the agreement between measures on the left and right side of the patient and measures 1 h apart by two bioelectrical impedance devices. Results are presented as Bland Altman plots with 95% Limits of Agreements (LoA) and as correlations between bioelectrical impedance analysis results and clinical markers of fluids. Forty-nine patients were included. The agreement between measures on the left and the right side of the patient and after 1 h was overall without bias, but with wide LoA's. Fluid overload 1 h apart showed the most narrow 95% LoA (-2.4-2.9L). The same wide limits of agreements were observed when comparing devices. For example, total body water with 95% LoA of -14.8-16.7L. Correlations between bioelectrical impedance analysis and clinical measures were low but statistically significant. In patients with septic shock bioelectrical impedance analysis had no systematic errors or bias, but wide limits of agreement, indicating that the devices have a large and uncorrectable random error. Fluid status by bioelectrical impedance analysis is not sufficiently accurate to guide treatment in this group of patients.

Evaluation of A Direct Regional Reprojection Reconstruction Method to Improve Quantitation of Amyloid and Tau PET Images using 3D Printed Phantoms

AbstractBackgroundImage reconstruction and partial volume correction (PVC) techniques designed to account for the limited spatial resolution of PET are used inconsistently in amyloid and tau PET imaging, likely due to a lack of characterization of the techniques and their unknown effect on reliability. In this study, we aimed to test the accuracy and reliability of a variety of reconstruction and image‐based correction methods using 3D‐printed PET phantoms.MethodTwo phantoms modeled on the lateral temporal brain region of two human subjects (67‐year‐old male and 69‐year‐old female, both cognitively normal) were created using 3D‐printing technology (Formlabs Form 3). The phantoms had six thin‐walled chambers corresponding to inferior, middle, and superior temporal grey matter (GM) and white matter (WM). Phantoms were scanned (Siemens Biograph mCT) multiple times as chambers were filled with F‐18 solution to mimic various distributions of activity seen in amyloid‐positive, amyloid‐negative, or tau‐positive subjects. 16 scans were completed in total. Data from each 3‐hour scan were binned into 16 statistically equivalent frames and reconstructed with three techniques: FBP, OSEM, and TrueX, a manufacturer‐supplied method including point spread function modeling (Figure 1). Two image‐based correction techniques were also applied and evaluated: Geometric Mean Transfer Matrix (GTM) PVC and a novel Direct Regional Reprojection Reconstruction (DRRR) method, an iterative algorithm that reprojects images directly into regions‐of‐interest. To evaluate accuracy, fractional error of each region (F = M/T ‐ 1, where M is the measured regional value averaged over 16 frames and T is the true regional value) was calculated. To evaluate reliability, the coefficient of variation (CV) of M over all 16 frames in each scan was assessed for every region of the phantoms.ResultFractional errors (Figure 2) and CVs (Figure 3) are shown for each reconstruction and image‐based correction method. Uncorrected TrueX fractional error was not apparently improved relative to uncorrected FBP and OSEM fractional error. For all reconstructions, GTM and DRRR improved accuracy relative to uncorrected. For the FBP and OSEM reconstructions, GTM was more accurate than DRRR, but DRRR was more reliable than GTM.ConclusionDRRR is a promising novel method for PET quantification that improves accuracy without compromising reliability.

Laser Induced Single Event Upset (SEU) Testing of Commercial Memory Devices with Embedded Error Correction Codes (ECC)

Results of laser-induced single event upset testing of devices with embedded error correction codes are described. Specifically, the memory system, consisting of a Micron MT41K256M16TW-107 IT: P 32 Meg×16×8 banks Dual Dynamic Random Access Memories (DDRs) was tested on a self-made test board. Two samples of each memory system or device type were irradiated with a pulsed laser. The units were irradiated by using a continual read/write correct loop in several bit patterns. Results for both correctable and uncorrectable errors are presented along with soft error data records.

Inhibitory Control of Saccadic Eye Movements and Cognitive Impairment in Mild Cognitive Impairment

AbstractBackgroundMild cognitive impairment (MCI) may occur due to several forms of neurodegenerative diseases and non‐degenerative conditions and is associated with cognitive impairment that does not affect everyday activities. For a timely diagnosis of MCI to prevent progression to dementia, a screening tool of fast, low‐cost and easy access is needed. Recent research on eye movement hints it a potential application for the MCI screening. However, the precise extent of cognitive function decline and eye‐movement control alterations in patients with MCI is still unclear.MethodPatients with MCI (n = 79) and age‐matched cognitively healthy controls (HC) (n = 170) completed four saccadic eye‐movement paradigms: prosaccade (PS)/antisaccade (AS), Go/No‐go, and a battery of neuropsychological tests.ResultThe findings revealed significantly longer latency in patients with MCI than in HC during the PS task. Additionally, patients with MCI had a lower proportion of correct responses and a marked increase in inhibition errors for both PS/AS and Go/No‐go tasks. Furthermore, when patients with MCI made errors, they failed to self‐correct many of these inhibition errors. In addition to the increase in inhibition errors and uncorrected inhibition errors, patients with MCI demonstrated a trend toward increased correction latencies. We also showed a relationship between neuropsychological scores and correct and error saccade responses.ConclusionOur results demonstrate that, similar to patients with Alzheimer’s dementia (AD), patients with MCI generate a high proportion of erroneous saccades toward the prepotent target and fail to self‐correct many of these errors, which is consistent with an impairment of inhibitory control and error monitoring.

PMON126 Null Cell Adenoma With Low Ki-67 Presenting as Recurrent Pituitary Mass

Abstract Background Pituitary adenomas account for 10% to 15% of all intracranial masses. Among these, approximately one-third are identified as nonfunctioning pituitary adenomas (NFPA) which have a heterogenous profile and an increased potential for relapse one to five years after pituitary surgery. In a retrospective analysis by Almeida et al,multiple surgical resections, elevated ki-67 and cavernous sinus invasion were predictive of recurrence. They typically present with symptoms of mass effect and most are macroadenomas at time of diagnosis. Clinical Case A 65-year-old female initially presented with bitemporal hemianopsia, galactorrhea and amenorrhea 28 years prior. She subsequently underwent transsphenoidal hypophysectomy with resolution of symptoms post operatively. She was clinically stable until 12 years after the surgery when she noted new onset peripheral visual field loss. Upon reevaluation, she was diagnosed with non-functioning pituitary macroadenoma for which she was advised gamma knife surgery but she opted a repeat transsphenoidal pituitary surgery. Her vision improved and she remained asymptomatic thereafter. Sixteen years after her second surgery, she developed blurring of vision. Cranial MRI was done which showed lobulated, heterogeneous hyperdense sellar-suprasellar mass measuring 55×36×47 mm extending to the bilateral sphenoid and ethmoid sinuses, left pterygopalatine fossa, left superior orbital fissure, probably the left foramen lacerum, and left cavernous sinus with encasement of the left internal carotid artery and associated erosion of the adjacent osseous structures. Visual field testing showed mild reduction in field sensitivity with consideration of media opacity and/or uncorrected error of refraction. Baseline hormonal work up was unremarkable. Hence, endoscopic endonasal transphenoidal, transethmoidal parasellar excision of sellar mass, with reconstruction via Hadad Flap was done. There were no intraoperative nor postoperative complications. The specimen was sent for histopathology with provisional anatomic diagnosis of pituitary adenoma. Immunohistochemistry stained negative for chromogranin and any of the pituitary hormones which was consistent with null cell adenoma. The Ki-67, an independent marker of tumor progression and recurrence, was low at less than 1%. However, after 1 month, repeat MRI showed  no significant change in the lobulated, heterogeneously enhancing mass centered in the sellar-suprasellar region. Thus, she received adjuvant radiotherapy with total dose of 5040cGy divided in 28 fractions and was advised close monitoring of pituitary MRI and/or development of any new symptoms. Conclusion In this case, although with low Ki-67, the presence of multiple surgeries and high Knosp grade were recognized as risk factors for its recurrence.Treatment of recurrent NFPA is multimodal which includes re-operation, radiosurgery and radiation therapy. A multidisciplinary team approach is required for its comprehensive management and long-term follow-up. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Evaluation of the dosimetric influence of interfractional 6D setup error in hypofractionated prostate cancer treated with IMRT and VMAT using daily kV-CBCT

IntroductionProstate cancer is one of the most common malignant tumors in men and is usually treated with advanced intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Significant uncorrected interfractional 6-Dimensional setup errors could impact the delivered dose. The aim of this study was to assess the dosimetric impact of 6D interfractional setup errors in hypofractionated prostate cancer using daily kilovoltage cone-beam computed tomography (kV-CBCT). MethodsThis retrospective study comprised twenty prostate cancer patients treated with hypofractionated IMRT (8) and VMAT (12) with daily kV-CBCT image guidance. Interfraction 6D setup errors along lateral, longitudinal, vertical, pitch, roll, and yaw axes were evaluated for 400 CBCTs. For targets and organs at risk (OARs), the dosimetric impact of rotational error (RError), translational error (TError), and translational plus rotational error (T+RError) were evaluated on kV-CBCT images. ResultsThe single fraction maximum TError ranged from 12–20 mm, and the RError ranged from 2.80–3.00. The maximum mean absolute dose variation ΔD in D98% (dose to 98% volume) of CTV-55 and PTV-55 was -0.66±0.82 and -5.94±3.8 Gy, respectively, in the T+RError. The maximum ΔD (%) for D98% and D0.035cc in CTV-55 was -4.29% and 2.49%, respectively, while in PTV-55 it was -24.9% and 2.36%. The mean dose reduction for D98% in CTV-55 and D98% and D95% in PTV-55 was statistically significant (p<0.05) for TError and T+RError. The mean dose variation for Dmean and D50% in the rectum was statistically significant (p<0.05) for TError and T+RError. ConclusionThe uncorrected interfractional 6D setup error results in significant target underdosing and OAR overdosing in prostate cancer. This emphasizes the need to correct interfractional 6D setup errors daily in IMRT and VMAT.

Rebirth-FTL: Lifetime Optimization via Approximate Storage for NAND Flash Memory

The lifetime of NAND flash cells significantly degrades with feature-size reductions and multilevel cell technology. On the other hand, we have more and more approximate data, such as images and videos that are more error tolerant than regular data like text. In this article, we propose Rebirth-FTL, which reuses faulty blocks that contain uncorrectable errors to store approximate data for lifetime optimization. Rebirth-FTL effectively manages two spaces, namely, the approximate space and the normal space, with an efficient address translator, a coordinated garbage collection, and a differential wear leveler. In addition, we develop an migration times restriction (MTR) policy to restrict the movement of the approximate data in the approximate space. We also develop a scheme to pass approximate information from userland to kernel space in Linux. Finally, a lifetime model is presented for lifetime analysis. Our experimental results show that Rebirth-FTL can extend the lifetime by 41.63% on average.

Foreground–background decoupling matting

Image matting aims to extract specific objects, deployed in many applications. Generally, the automatic matting methods need an extra before overcome the intricate details and the diverse appearances. Recently, the matting community has paid more attentions to the investigation of trimap-free matting direction to address the dependency of priors. Most trimap-free approaches divide the matting task into global segmentation and detail matting subtasks. Unfortunately, these methods suffer from stagewise modeling, uncorrectable errors, or subtasks bottleneck problems. To address these issues, we propose a new set of matting subtasks, including foreground segmentation, background segmentation, and disambiguation. And we present a novel Foreground–Background Decoupling Matting (FBDM) network motivated by the new subtasks. Specifically, we first design a nested attention mechanism to decouple the backbone features. Then, we utilize two independent progressive semantic decoders by the decoupling features to complete the foreground and background segmentation subtasks. Finally, we utilize multiple of the proposed frequency division local disambiguation modules to achieve the disambiguation subtask. Besides, we establish a challenging potted plant (PPT) benchmark which contains 100 potted plants images in the real world for the matting community. Extensive experiments on several public benchmarks and the PPTs benchmark demonstrate that the proposed FBDM generates the best results compared with the state-of-the-art trimap-free methods.

PinchText: One-Handed Text Entry Technique Combining Pinch Gestures and Hand Positions for Head-Mounted Displays

This paper presents PinchText, a mid-air technique with a condensed keys-based keyboard, which combines hand positions and pinch gestures, enabling one-handed text entry for Head-mounted displays (HMDs). Firstly, we conduct Study 1 to collect and analyze the typing data of PinchText with two arm postures and two movement directions, obtaining the range of hand position corresponding to the middle key set. Then, we conduct Study 2, a 6-block experiment, finding that PinchText with Hand-Up Vertical (UpV) and Hand-Down Vertical (DownV) modes could achieve a speed of 12.71 words-per-minute (WPM) and 11.14 WPM respectively with both uncorrected error rates less than 0.5%, which is 71% faster than the index finger pinch-based technique. Finally, Study 3 is conducted to explore the potential of reducing the size of the decoupled visual keyboard of PinchText, verifying that the occlusion of the virtual keyboard can be decreased. Overall, PinchText is an efficient, easy-to-learn, and comfortable text entry technique for HMDs.

Error correction improvement based on weak-bit-flipping for resistive memories

Resistive memories are affected by significant error rates tied to structural relaxation and wear out of the resistive memory devices. A way to reduce the need for strong error-correcting codes (ECCs) is to improve error correction based on the weak bits, i.e., potentially faulty bits, identified in sensed memory words. Here, it is formally proven that conventional ECC decoders reinforced with weak-bit-flipping may achieve similar error correction capability as theoretical generalized-minimum-distance decoders. It is shown that weak-bit-flipping may reduce the uncorrectable bit error rate (UBER) by orders of magnitude when applied in conjunction with single-error-correcting and double-error-detecting (SEC-DED) or double-error-correcting and triple-error-detecting (DEC-TED) codes. In particular, weak-bit-information extracted from a 2T2R memory and used to reinforce a DEC-TED code with a conventional decoder may enable an UBER that is one order of magnitude better than the UBER achieved with a triple-error-correcting (TEC) code and a conventional decoder.

Characterizing and Mitigating Soft Errors in GPU DRAM

While graphics processing units (GPUs) are used in high-reliability systems, wide GPU dynamic random-access memory (DRAM) interfaces make error protection difficult, as wide-device correction through error checking and correcting (ECC) is expensive and impractical. This challenge is compounded by worsening relative rates of multibit DRAM errors and increasing GPU memory capacities. This work uses high-energy neutron beam tests to inform the design and evaluation of GPU DRAM error-protection mechanisms. Based on observed locality in multibit error patterns, we propose several novel ECC schemes to decrease the silent data corruption (SDC) risk by up to five orders of magnitude relative to single-bit-error-correcting and double-bit-error-detecting (SEC-DED) ECC, while also reducing the number of uncorrectable errors by up to 7.87×. We compare novel binary and symbol-based ECC organizations that differ in their design complexity and hardware overheads, ultimately recommending two promising organizations. These schemes replace SEC-DED ECC with no additional redundancy, likely no performance degradation, and modest area and complexity costs.

Reprint of Implementation of a pharmacist-led ARVSP in an academic hospital to reduce ART errors

The primary objective was to compare the percentage of Antiretroviral Therapy (ART) uncorrected errors during hospital admission before and after the implementation of an Antiretroviral Stewardship Program (ARVSP). This was a 2-year single-center, pre-post quality improvement study. Included in the study were admitted patients at least 18 years of age, diagnosed with human immunodeficiency virus (HIV), and taking at least 1 antiretroviral. The baseline percentage of uncorrected ARV errors was retrospectively determined during the first year. The second year consisted of implementing an ARVSP that prospectively audited ART orders. The ARVSP consisted of a pharmacy resident, a medical resident, an infectious disease, HIV trained pharmacist, an infectious disease physician, and ancillary health care providers. The impact of the ARVSP was assessed by comparing the percentage of uncorrected errors between the 2 time periods. The number of uncorrected errors were 64.1% versus 31.1% before and after ARVSP implementation, respectively (P < 0.05). Delay in therapy errors were statistically significantly reduced (30.1% vs. 22.2%; P < 0.05). The time to overall correction of any error before ARVSP was 3.1 days, and after ARVSP, it was 1.8 days (P= 0.11). Implementation of an ARVSP reduces the number of uncorrected antiretroviral-related errors. Because health care resources are finite and focused on the acute care of hospitalized patients, this multidisciplinary practice model may provide a practical approach for similar institutions to improve antiretroviral stewardship surveillance in the inpatient setting.

A Low Bit-Width LDPC Min-Sum Decoding Scheme for NAND Flash

For NAND flash memory, designing a good low-density parity-check (LDPC) decoding algorithm could ensure data reliability. When the decoding algorithm is implemented in hardware, it is necessary to achieve an attractive tradeoff between implementation complexity and decoding performance. In this article, a novel low-bit-width decoding scheme is introduced. In this scheme, the quasi-cyclic LDPC (QC-LDPC) is used, and the row-layered normalized min-sum algorithm is improved by restricting the amplitude of minimum and second-minimum values in each check node (CN) updating. The simulation shows that our approach achieves a lower uncorrectable bit error rate (UBER) with a negligible increase in computational complexity, especially with low-precision input log-likelihood ratio (LLR).

Refractive errors in children

When the eye fails to perfectly focus a light beam from an element onto the retinal surface, refractive error occurs. The individual's perception of the resultant image is fuzzy, and refraction correction is required to see correctly. Hypermetropia or hyperopia, sometimes known as "Long or Far-sightedness," presbyopia, and astigmatism are all examples of refractive insufficiency. Children’s vision is important for their development since it allows them to interact with their surroundings. Preschool children's eyesight is critical since their sensory systems are still developing and they are at risk of acquiring Amblyopia or Anisometropia. Refraction errors are also risk factors for a variety of ocular disorders. Uncorrected refraction errors are a common cause of vision impairment and can lead to lost productivity. Refractive error, along with cataract, trachoma, onchocerciasis, and infantile blindness, has been highlighted as a vision disease for which early detection and treatment will result in significant cost savings and socioeconomic growth. Uncorrected Refractive Error affects around 150 million people globally, with 8 million of them effectively blind.

Renz: An R package for the analysis of enzyme kinetic data

BackgroundComplex enzymatic models are required for analyzing kinetic data derived under conditions that may not satisfy the assumptions associated with Michaelis–Menten kinetics. To analyze these data, several software packages have been developed. However, the complexity introduced by these programs is often dispensable when analyzing data conforming to the canonical Michaelis–Menten model. In these cases, the sophisticated routines of these packages become inefficient and unnecessarily intricated for the intended purpose, reason for which most users resort to general-purpose graphing programs. However, this approach, in addition of being time-consuming, is prone to human error, and can lead to misleading estimates of kinetic parameters, particularly when unweighted regression analyses of transformed kinetic data are performed.ResultsTo fill the existing gap between highly specialized and general-purpose software, we have developed an easy-to-use R package, renz, designed for accurate and efficient estimation of enzyme kinetic parameters. The package provides different methods that can be clustered into four categories, depending on whether they are based on data fitting to a single progress curve (evolution of substrate concentration over time) or, alternatively, based on the dependency of initial rates on substrate concentration (differential rate equation). A second criterion to be considered is whether the experimental data need to be manipulated to obtain linear functions or, alternatively, data are directly fitted using non-linear regression analysis. The current program is a cross-platform, free and open-source software that can be obtained from the CRAN repository. The package is accompanied by five vignettes, which are intended to guide users to choose the appropriate method in each case, as well as providing the basic theoretical foundations of each method. These vignettes use real experimental data to illustrate the use of the package utilities.Conclusionsrenz is a rigorous and yet easy-to-use software devoted to the analysis of kinetic data. This application has been designed to meet the needs of users who are not practicing enzymologists, but who need to accurately estimate the kinetic parameters of enzymes. The current software saves time and minimizes the risk of making mistakes or introducing biases due to uncorrected error propagation effects.

PVSensing: A Process-Variation-Aware Space Allocation Strategy for 3D NAND Flash Memory

Three-dimensional (3D) flash memory is an emerging memory technology that enables a number of improvements to conventional planar NAND flash memory, including larger capacity, less program disturb, and lower access latency. Despite these advantages, 3D flash memory brings a number of new challenges. First, in 3D flash memory, NAND strings punch through multiple stacked layers to form the 3D infrastructure. Current etching process is unable to manufacture perfect channels with identical feature size. Second, with more stacked layers, the cell current in 3D flash memory is only 20% compared to planar flash memory, making it difficult to give a reliable sensing margin. These issues are affected by process variation, and they pose threats to the integrity of data stored in 3D flash memory. This article present <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PVSensing</i> , a process-variation-aware space allocation strategy for open-channel SSD with 3D charge-trap flash memory. PVSensing is a novel hardware and file system interface that can transparently allocate physical space in the presence of process variation. PVSensing utilizes the rich functionalities provided by the system infrastructure of open-channel SSD to reduce the uncorrectable bit errors. Three reliability enhancement strategies (i.e., the adaptive creation of fault cubes, the physical block mining, and the live migration of write requests) are proposed. We demonstrate the viability of the proposed technique using a set of extensive experiments. Experimental results show that PVSensing can effectively reduce uncorrectable bit errors, and improve the reliability of critical data with negligible extra erase operations in comparison with representative schemes.

PO-1704 Dosimetric effect of uncorrected rotational errors during prostate SBRT Cyberknife treatments.

PO-1704 Dosimetric effect of uncorrected rotational errors during prostate SBRT Cyberknife treatments.