Image Radiation Research Articles

Audit Dosis dan Optimisasi Pemeriksaan CT Scan Kepala: Studi Multisenter

One of the principles of radiation protection is optimizing radiation dose and image quality. Dose audits and optimization of head CT scans for the adult patient category have been carried out in Hospital A and Hospital B. The research at Hospital A started with a dose audit, revealing that the typical values of CTDIvol and DLP were above the IDRL, and optimization of patient radiation dose was necessary. The optimization strategy at Hospital A involved a gradual selection of exposure factor combinations. In the first stage, a manufactured dedicated water phantom scan was performed with voltage 80, 100, and 120 kVp variations while the current remained constant. Based on image quality evaluation using the Noise Power Spectrum (NPS) method, the lowest NPS was obtained at voltage 120 kV, which was 19,47 HU2mm2. In the second stage, using voltage 120 kVp, a head rando phantom scan was performed with variations of current 100, 150, 200, 250, 300, 350, 400, and 450 mAs. 40% of the radiologists chose the exposure factor combination voltage 120 kVp and current 350 mAs as the combination producing image with the most preferable quality. When comparing the voltage and current combinations before and after optimization with the IDRL, there was a decrease of 7.9% and 2.1% in CTDIvol and DLP. Meanwhile, the dose audit results at Hospital B revealed that the typical value of CTDIvol was already below the IDRL. Still, the typical value of DLP was above the IDRL, so optimization of patient radiation dose for patient-related parameters was necessary. The optimization strategy at Hospital B involved creating new protocols based on exposure factors obtained from image quality evaluation using the NPS method and the interpretation of radiologists. The optimization results with a comparison of four protocols showed that protocol 3 was the most optimal using the exposure factors: collimation 40 × 0.625, the pitch of 0.2, the scan time of 13.8 seconds, Dose Right Index of 25, voltage 120 kVp, and current 144 mAs. The implementation of this protocol contributed to a 67.7% reduction in CTDIvol and a 53.6% reduction in DLP compared to the IDRL. The research objective is to obtain the optimal combination of exposure factors with radiation dosage and image quality as an initial optimization implementation. Keywords: dose audit, radiation protection, optimization, diagnostic reference levels

Preface

It is a matter of great pleasure for the organizers to bring out the Conference proceedings of the 6th National Conference on Advanced Materials and Radiation Physics (AMRP-2023) in Journal of Physics: Conference Series. The 6th National Conference on Advanced Materials and Radiation Physics (AMRP-2023) was held during May 18-19, 2023 through HYBRID Mode at Sant Longowal Institute of Engineering and Technology, Longowal, Punjab (INDIA). The AMRP-2023 conference is an important event that brings academics and researchers from all over India to share their professional experiences, expand their professional knowledge and receive updates on the latest advances in the field of advanced materials and radiation Physics.Materials science is an interdisciplinary field which deals with the discovery and design of new materials involving the study of materials through the materials paradigm (synthesis, structure, properties and performance). The subject covers a broad spectrum of materials science research including functional materials, synthesis and processing, theoretical analyses, characterization and properties of materials. Emphasis is also placed on the interdisciplinary nature of materials science and issues at the forefront of the field, such as energy and environmental issues, as well as medical and bioengineering applications are also discussed.The Radiation Physics is highly multidisciplinary in nature and is now the backbone of the nuclear medical diagnostics. The radiation physics research covers many areas of radiation imaging techniques, fundamental studies of semiconductor radiation detectors, detector materials, radiation interaction with matter and medical physics which aims to improve knowledge and methods in the field of radiation physics and radiation dosimetry, in order to develop new radiation measurement instruments and methods for applications in research, industry and medicine.In this conference more than 150 researchers from reputed universities/institutes have shown interest in hybrid mode participation. The conference included one key note address, four plenary talks, six invited talks, and presentation of more than 130 contributed papers via online & offline mode on different aspects of the conference theme. We extend our sincere gratitude to all the authors who submitted their papers to the AMRP conference. We also like to express our great appreciation to the Keynote, plenary and invited speakers.We are thankful to Institute administration for extending all support and motivation to organize this conference. On behalf of the Conference Organizing Committee, we would like to thank the referees for their efficient and thoughtful actions. We are grateful to the members of the Organising Committee for their efforts in making and shaping the program for AMRP 2023. Particularly, we acknowledge the publishing support from the members of Journal of Physics: Conference Series. We hope that the future AMRP will be as successful and stimulating, as indicated with the contributions presented in this volume.Organising Committee AMRP-2023List of Organising Committee is available in this Pdf.

Generalization ability of a CNN γ-ray localization model for radiation imaging

Generalization ability of a CNN γ-ray localization model for radiation imaging

Photon-Counting Detector CT Versus Energy-Integrating Detector CT of the Lumbar Spine: Comparison of Radiation Dose and Image Quality.

BACKGROUND. Photon-counting detector (PCD) CT could be useful to help address the typically high radiation doses of conventional energy-integrating detector (EID) CT of the lumbar spine. OBJECTIVE. The purpose of our study was to compare PCD CT and EID CT of the lumbar spine, both performed using tin filtration, in terms of radiation dose and image quality. METHODS. This study included a prospective sample of 39 patients (22 men, 17 women; mean age, 27.2 years) who underwent investigational PCD CT of the lumbar spine as part of a separate study and a retrospective sample of 39 patients (22 men, 17 women; mean age, 34.9 years) who underwent clinically indicated EID CT of the lumbar spine. In both groups, all examinations were performed using unenhanced technique with tin prefiltration between June 2022 and January 2023. Patients were matched between groups using age, sex, and BMI. A custom gaussian curve-fitting algorithm was used to automatically calculate image noise, SNR, and CNR for each examination, on the basis of all voxels within the image set. Three radiologists independently reviewed examinations to perform a subjective visual assessment of visualization of trabecular architecture, cortical bone, neuroforaminal content, paraspinal muscles, and intervertebral disk, as well as overall image quality, using a 4-point Likert scale (1 = poor, 4 = excellent). PCD CT and EID CT examinations were compared. RESULTS. Mean CTDIvol was 4.4 ± 1.0 (SD) mGy for PCD CT versus 11.1 ± 1.9 mGy for EID CT (p < .001). Mean size-specific dose estimate (SSDE) was 6.2 ± 1.0 (SD) mGy for PCD CT versus 14.2 ± 1.8 mGy for EID CT (p < .001). PCD CT and EID CT examinations were not significantly different in terms of image noise or SNR (both p > .05). PCD CT, in comparison with EID CT, showed significantly higher CNR (mean ± SD, 33.6 ± 3.3 vs 29.3 ± 4.1; p < .001). For all three readers, the median score for overall image quality was 4 (range, 3-4) for both PCD CT and EID CT. PCD CT and EID CT examinations showed no significant difference in terms of any qualitative measure for any reader (all p > .05). CONCLUSION. PCD CT, in comparison with EID CT, yielded significantly lower radiation dose with preserved image quality. CLINICAL IMPACT. The findings support expanded use of PCD CT for lumbar spine evaluation.

The Dose Optimization and Evaluation of Image Quality in the Adult Brain Protocols of Multi-Slice Computed Tomography: A Phantom Study.

Computed tomography examinations have caused high radiation doses for patients, especially for CT scans of the brain. This study aimed to optimize the radiation dose and image quality in adult brain CT protocols. Images were acquired using a Catphan 700 phantom. Radiation doses were recorded as CTDIvol and dose length product (DLP). CT brain protocols were optimized by varying parameters such as kVp, mAs, signal-to-noise ratio (SNR) level, and Clearview iterative reconstruction (IR). The image quality was also evaluated using AutoQA Plus v.1.8.7.0 software. CT number accuracy and linearity had a robust positive correlation with the linear attenuation coefficient (µ) and showed more inaccurate CT numbers when using 80 kVp. The modulation transfer function (MTF) showed a higher value in 100 and 120 kVp protocols (p < 0.001), while high-contrast spatial resolution showed a higher value in 80 and 100 kVp protocols (p < 0.001). Low-contrast detectability and the contrast-to-noise ratio (CNR) tended to increase when using high mAs, SNR, and the Clearview IR protocol. Noise decreased when using a high radiation dose and a high percentage of Clearview IR. CTDIvol and DLP were increased with increasing kVp, mAs, and SNR levels, while the increasing percentage of Clearview did not affect the radiation dose. Optimized protocols, including radiation dose and image quality, should be evaluated to preserve diagnostic capability. The recommended parameter settings include kVp set between 100 and 120 kVp, mAs ranging from 200 to 300 mAs, SNR level within the range of 0.7-1.0, and an iterative reconstruction value of 30% Clearview to 60% or higher.

Editorial: Advanced signal processing techniques in radiation detection and imaging

Editorial: Advanced signal processing techniques in radiation detection and imaging

Novel Deep Learning Denoising Enhances Image Quality and Lowers Radiation Exposure in Interventional Bronchial Artery Embolization Cone Beam CT

In interventional bronchial artery embolization (BAE), periprocedural cone beam CT (CBCT) improves guiding and localization. However, a trade-off exists between 6-second runs (high radiation dose and motion artifacts, but low noise) and 3-second runs (vice versa). This study aimed to determine the efficacy of an advanced deep learning denoising (DLD) technique in mitigating the trade-offs related to radiation dose and image quality during interventional BAE CBCT. This study included BMI-matched patients undergoing 6-second and 3-second BAE CBCT scans. The dose-area product values (DAP) were obtained. All datasets were reconstructed using standard weighted filtered back projection (OR) and a novel DLD software. Objective image metrics were derived from place-consistent regions of interest, including CT numbers of the Aorta and lung, noise, and contrast-to-noise ratio. Three blinded radiologists performed subjective assessments regarding image quality, sharpness, contrast, and motion artifacts on all dataset combinations in a forced-choice setup (-1=inferior, 0=equal; 1=superior). The points were averaged per item for a total score. Statistical analysis ensued using a properly corrected mixed-effects model with post hoc pairwise comparisons. Sixty patients were assessed in 30 matched pairs (age 64±15 years; 10 female). The mean DAP for the 6s and 3s runs was 2199±185 µGym² and 1227±90 µGym², respectively. Neither low-dose imaging nor the reconstruction method introduced a significant HU shift (p≥0.127). The 3s-DLD presented the least noise and superior contrast-to-noise ratio (CNR) (p<0.001). While subjective evaluation revealed no noticeable distinction between 6s-DLD and 3s-DLD in terms of quality (p≥0.996), both outperformed the OR variants (p<0.001). The 3s datasets exhibited fewer motion artifacts than the 6s datasets (p<0.001). DLD effectively mitigates the trade-off between radiation dose, image noise, and motion artifact burden in regular reconstructed BAE CBCT by enabling diagnostic scans with low radiation exposure and inherently low motion artifact burden at short examination times.

Modification of 3 MSCT Parameters Using Iterative Reconstruction Techniques for Radiation Dose, Image Quality, and Anatomical Information

Cardiovascular Computed Tomography Angiography (CCTA) examination in diagnosing and evaluating congenital heart disease in pediatrics can make radiation exposure controversial and can lead to cancer risk. Development of parameter settings or modifications, namely tube voltage (kVp), pitch, and rotation time as an effort to optimize radiation dose to produce very low radiation dose. Apart from that, iterative reconstruction techniques are used as a reconstruction method to reduce noise to improve image quality. This study aimed to determine the effect of modifying 3 parameters using the iterative reconstruction technique on radiation dose, image quality, and anatomical information in pediatric CCTA examinations with clinical congenital heart disease at Harapan Kita Heart Hospital. Experimental research with a nonequivalent design. The results of this research are that the modification of 3 MSCT parameters and the iterative reconstruction technique produces a very low radiation dose which is significant at p = 0.000, with an average CTDIvol of 0.314 mGy, DLP 5.518 mGy.cm and can maintain different but not significant image quality, namely p = 0.72 in pulmonary artery SNR, p = 0.88 in ascending aorta SNR, p = 0.37 in pulmonary artery CNR and p = 0.41 in ascending aorta CNR so that it can provide anatomical information on contrast enhancement in the aorta and pulmonary artery area p = 0.02, extra cardiac analysis p = 0.04, contrast filling atria and ventricles p = 0.05, arterial and venous abnormalities p = 0.01, artifacts p = 0.17. Anatomical information is still informative in making a diagnosis. This study used a sample of 30 patients in the control group and intervention group using a purposive sampling method. Modification of 3 MSCT parameters with iterative reconstruction techniques provides an important contribution to the development of safe and informative scanning techniques for diagnosis.

Improving the Time Resolution of Large-Area LaBr3:Ce Detectors with SiPM Array Readout

LaBr3:Ce crystals have good scintillation properties for X-ray spectroscopy. Initially, they were introduced for radiation imaging in medical physics with either a photomultiplier or SiPM readout, and they found extensive applications in homeland security and gamma-ray astronomy. We used 1″ round LaBr3:Ce crystals to realize compact detectors with the SiPM array readout. The aim was a good energy resolution and a fast time response to detect low-energy X-rays around 100 keV. A natural application was found inside the FAMU experiment, at RIKEN RAL. Its aim is a precise measurement of the proton Zemach radius with impinging muons, to contribute to the solution to the so-called “proton radius puzzle”. Signals to be detected are characteristic X-rays around 130 KeV. A limit for this type of detector, as compared to the ones with a photomultiplier readout, is its poorer timing characteristics due to the large capacity of the SiPM arrays used. In particular, long signal falltimes are a problem in experiments such as FAMU, where a “prompt” background component must be separated from a “delayed” one (after 600 ns) in the signal X-rays to be detected. Dedicated studies were pursued to improve the timing characteristics of the used detectors, starting from hybrid ganging of SiPM cells; then developing a suitable zero pole circuit with a parallel ganging, where an increased overvoltage for the SiPM array was used to compensate for the signal decrease; and finally designing ad hoc electronics to split the 1″ detector’s SiPM array into four quadrants, thus reducing the involved capacitances. The aim was to improve the detectors’ timing characteristics, especially falltime, while keeping a good FWHM energy resolution for low-energy X-ray detection.

Drought-Tolerance Screening of Date Palm Cultivars under Water Stress Conditions in Arid Regions

Drought stress poses a considerable challenge to agriculture sustainability in arid regions. Water scarcity severely affects date palm growth and productivity in these regions. However, as water resources become increasingly scarce in arid regions, understanding the drought tolerance of date palm cultivars becomes imperative for developing drought-resistant cultivars and optimizing irrigation water usage for sustainable agriculture. This research examines the impact of different drought stress levels based on evapotranspiration (ETc), i.e., 40%, 60%, 80%, and 100% ETc, and time intervals (0, 6, 12, 18, and 24 months) on leaf growth, net photosynthesis, chlorophyll a and b content, and leaf relative water content (LRWC) of four prominent date palm cultivars, Khalas, Barhee, Hilali, and Ashrasee. In addition, the study also examines the effects of drought stress on dry weight, potassium and calcium content of leaf, stem, and root, and proline content in fresh leaves of these four cultivars. A solar-powered drip irrigation system with automated time-based irrigation scheduling was used to accurately control the irrigation water amount. To real-time estimate ETc in the study area, meteorological data were collected using a cloud-based IoT system. The findings of this study revealed that severe drought conditions (40 and 60 % ETc) significantly reduced leaf growth, plant dry biomass, and physiological and biochemical attributes; however, date palm cultivars can be grown under moderate drought conditions (80% ETc) with minimal effect on phenotypic, physiological, and biochemical traits to conserve water. The study also revealed that the drought-related characteristics decreased gradually with an increase in water stress time over 24 months. Comparing the date palm cultivars revealed that the Khalas and Barhee cultivars are more drought-tolerant, followed by Hilali, while Ashrasee is susceptible. The study elucidated a water conservation strategy employed in response to drought-induced stress based on the physiological and morphological parameters of date palm cultivars. It provides valuable insights into irrigation practices in arid regions. However, future studies can be focused on other nondestructive innovative techniques such as pulse-amplitude-modulation (PAM) fluorimetry, infrared radiation (IR), and video imaging system (VIS) methods to identify drought stress in date palms.

Radiological protection in human research ethics using a case study: toward update of the ICRP Publication 62

The benefits of biomedical research involving humans are well recognised, along with the need for conformity to international standards of science and ethics. When human research involves radiation imaging procedures or radiotherapy, an extra level of expert review should be provided from the point of view of radiological protection. The relevant publication of the International Commission for Radiological Protection (ICRP) is now three decades old and is currently undergoing an update. This paper aims to provoke discussions on how the risks of radiation dose and the benefits of research should be assessed, using a case study of diagnostic radiology involving volunteers for whom there is no direct benefit. Further, the paper provides the current understanding of key concepts being considered for review and revision—such as the dose constraint and the novel research methods on the horizon, including radiation biology and epidemiology. The analysis revisits the perspectives described in the ICRP Publication 62, and considers the recent progress in both radiological protection ethics and medical research ethics.

Abstract 16045: Fluoroless Arterial Access and Closure for VT Ablation: Feasibility and Safety of an Ultrasound Guided Landmark Approach

Introduction: Ultrasound (US) guided access has become the gold standard of care for central access cannulation. The FAUST1 trial demonstrated that routine real-time US guidance was equivalent to fluoroscopic guidance but improved common femoral artery (CFA) access success and reduced complications in patients with high CFA bifurcations. The utilization of non radiation imaging modalities over the past decade has resulted in significantly reduced radiation exposure and orthopedic problems associated with prolonged electrophysiology procedures2. Hypothesis: Why do many operators still use fluoroscopy and arteriograms in addition to ultrasound guided access? Methods: A prospective single center multi-operator study was performed on patients undergoing premature ventricular contractions (PVC) or Ventricular Tachycardia (VT) ablation with arterial access. CFA access was obtained using a US guided landmark identification protocol. US probe is utilized in short and long access to identify upper and lower borders of the femoral head in relation to the CFA bifurcation. CFA access is then obtained with a modified Seldinger approach within femoral head landmarks. After arterial sheath insertion, the artery is again evaluated for closure appropriateness, assessed by absence of arterial calcifications within 5mm of arrteriotomy or stenosis &lt;5mm in diameter. Results: 20 consecutive patients undergoing PVC or PVT ablation were included. All patients underwent US only guided access to the right common femoral artery. All patients underwent successful closure with a hemostasis device. There were no vascular complications. Conclusions: Real-time US only guided CFA access is feasible and safe. Appropriate utilization of US is sufficient to avoid intravenous contrast and radiation exposure without increased complication rate.

Silicon Carbide Timepix3 detector for quantum-imaging detection and spectral tracking of charged particles in wide range of energy and field-of-view

The hybrid architecture of the Timepix (TPX) family of detectors enables the use of different semiconductor sensors, most commonly silicon (Si), as well as high-density materials such as Cadmium Telluride (CdTe) or Gallium Arsenide (GaAs). For this purpose, we explore the potential of a silicon carbide (SiC) sensor bump-bonded on a Timepix3 detector as a radiation imaging and particle tracking detector. SiC stands as a radiation-hard material also with the ability to operate at elevated temperatures up to several hundreds of degrees Celsius. As a result, this sensor material is more suitable for radiation harsh environments compared to conventional e.g., Si sensors. In this work, we evaluate the response for precise radiation spectrometry and high-resolution particle tracking of newly developed SiC Timepix3 detector which is built and operated as a compact radiation camera MiniPIX-Timepix3 with integrated readout electronics. Calibration measurements were conducted with mono-energetic proton beams with energies of 13, 22, and 31 MeV at the U-120M cyclotron at the Nuclear Physics Institute Czech Academy of Science (NPI CAS), Prague, as well as 100 and 226 MeV at the Proton Therapy Center Czech (PTC) in Prague. High-resolution pattern recognition analysis and single-particle spectral tracking are used for detailed inspection and understanding of the sensor response. Results include distributions of deposited energy and linear energy transfer (LET) spectra. The spatial uniformity of the pixelated detector response is examined in terms of homogeneously distributed deposited energy.

Bending Magnet Synchrotron Radiation Imaging with Large Orbital Collection Angles.

Synchrotron radiation (SR) from bending magnets, wigglers, and undulators is now extensively produced for users at storage ring based light sources, with unique properties in terms of average brightness and stability. We present a profound study of bending magnet SR intensity distribution in the image plane of a focusing optical system. Measurements of this intensity distribution at the MAX-IV low emittance storage ring are compared to theoretical predictions, and found to be in excellent agreement. This work shows upon the possibility of performing high resolution emittance diagnostics with visible or near-visible SR on upcoming low-emittance storage ring based light sources. As a byproduct of our study, we derive a closed analytical expression for the intensity distribution from a zero-emittance beam, in the limiting case of wide orbital collection angles. This expression finally allows us to demonstrate the meeting between classical electrodynamics applied to SR emission and focusing, and the Landau and Lifshitz prediction of radiation intensity distribution nearby a caustic.

Optimizing Radiation Dose Using Ctdi Value Analysis and Image Quality in the Thorax Low Dose CT Scan (LDCT) Technique with Reduced Dose Variations Using Idose Software

Radiation exposure to patients with higher cumulative effective doses on thorax CT scanning is very detrimental for cancer patients undergoing follow-up and raises the level of concern about the harmful effects of radiation doses received by patients. Reducing the tube voltage will reduce the radiation dose and image quality. To maintain good image quality, the iDose strength level is set. iDose is able to reduce radiation dose and improve image quality by maintaining low noise. Analyze the optimization of radiation dose and image quality in the thorax Low Dose CT Scan (LDCT) examination protocol with tube voltage settings and variations in the use of iDose software. This type of research is True-Experimental research with a Posttest-Only Control Design. The object used is a water phantom with tube voltage settings of 80 kVp, 100 kVp and 120 kVp and the use of iDoe 3 -5. Assessment includes radiation dose, noise, SNR and NPS. After getting optimal results from setting the tube voltage and iDose strength level, these results were applied to a Thorax CT Scan examination in patients, and a subjective assessment of image quality was carried out. Reducing the tube voltage (kVp) from 120 kV to 80 kV was able to reduce the radiation dose by 69.8%, and reducing the tube voltage from 120 kV to 100 kV in the Thorax CT Scan protocol was able to reduce the radiation dose by 34.2 %. There is an influence of setting the tube voltage and setting the iDose strength level on the radiation dose and image quality of the Low Dose CT Scan of the Thorax. Setting tube voltage and high iDose strength levels can improve image quality in CT scans, characterized by decreasing noise and NPS values and increasing SNR values. Tube voltage settings and iDose level settings affect the radiation dose and image quality. The use of a tube voltage of 80 kVp and strength level iDose 5 is able to provide optimal radiation dose and image quality on Thorax Low Dose CT Scan.

Label-free timing analysis of SiPM-based modularized detectors with physics-constrained deep learning

Pulse timing is an important topic in nuclear instrumentation, with far-reaching applications from high energy physics to radiation imaging. While high-speed analog-to-digital converters become more and more developed and accessible, their potential uses and merits in nuclear detector signal processing are still uncertain, partially due to associated timing algorithms which are not fully understood and utilized. In this paper, we propose a novel method based on deep learning for timing analysis of modularized detectors without explicit needs of labeling event data. By taking advantage of the intrinsic time correlations, a label-free loss function with a specially designed regularizer is formed to supervise the training of neural networks (NNs) towards a meaningful and accurate mapping function. We mathematically demonstrate the existence of the optimal function desired by the method, and give a systematic algorithm for training and calibration of the model. The proposed method is validated on two experimental datasets based on silicon photomultipliers as main transducers. In the toy experiment, the NN model achieves the single-channel time resolution of 8.8 ps and exhibits robustness against concept drift in the dataset. In the electromagnetic calorimeter experiment, several NN models (fully-connected, convolutional neural network and long short-term memory) are tested to show their conformance to the underlying physical constraint and to judge their performance against traditional methods. In total, the proposed method works well in either ideal or noisy experimental condition and recovers the time information from waveform samples successfully and precisely.

Use of Low Melting Point Alloy Mcp-96 Filter on Gammagraphic Optimization of Patient Position Verification with Telecobalt 60 Machine

Verification of the patient's position is a stage in external radiotherapy that aims to ensure the accuracy of radiation therapy administration according to plan. Equipment for the patient position verification process that is often used is Electronic Portal Image Devices (EPID) and film portals. However, not all Telecobalt 60 machines are equipped with EPID, so it requires alternative equipment to verify patient positions. One modality that can be utilized is Computed Radiography (CR). The study was conducted to analyze the use of MCP-96 low melting point alloy filters in imaging, verifying patient positions with CR devices on telecobalt 60 machine can calibrate radiation doses and provide good image quality and anatomical information. The study used a posttest-only control group design by comparing radiation dose, image quality, and anatomical information of the patient's position verification image. Imaging was performed using a phantom pelvis as an object and using CR equipment and low melting point alloy MCP-96 as a filter. The results showed that low melting points alloy MCP-96 with a thickness of 1 cm, 2 cm and 4 cm can calibrate the radiation dose output of the telecobalt 60 machine in accordance with recommendations for kilovoltage imaging. There was no significant difference in SNR and CNR images from imaging verification of patient positions with filter thicknesses of 1 cm, 2 cm, and 4 cm. Filter thickness of 1 cm produces images with optimal image quality and anatomical information in gammagraphic imaging verification of patient position using CR on telecobalt 60 machine. Thus, the use of low melting point alloy MCP-96 thickness of 1 cm and CR devices can be used in gammagraphic imaging of patient position verification on a telecobalt 60 machine as an alternative if you do not have EPID.

JUSTIFIKASI PROTOKOL COMPUTED TOMOGRAPHY CARDIAC PROSPECTIVE DAN RETROSPECTIVE DITINJAU DARI ANALISIS KUALITAS CITRA DAN ESTIMASI DOSIS RADIASI

Cardiac CT is an imaging technique that detects the condition of the coronary arteries. EKG-triggered techniques are used to improve the resolution of coronary artery images and minimize artifacts caused by cardiac motion. Retrospective cardiac computed tomography remains the first choice for maximum image quality, especially in relative contraindications such as arrhythmias and high heart rates during the cardiac cycle. The prospective technique can significantly reduce the radiation dose compared with the retrospective technique. This study aimed to see the effectiveness of this prospective technique in terms of radiation dose and image quality. The effective dose analysis method is with indoseCT software and calculated with a formula from CTDIvol and DLP. Image quality was assessed by calculating the SNR by comparing prospective and retrospective techniques. The study results regarding image quality show that the retrospective method has an SNR value of 44, and the SNR value of the prospective method is 35. Dose estimation by indoseCT software obtained results. Retrospective techniques yield the following results: The effective dose is 24.09 mSv, and the prospective technique provides an effective dose of 12.54 mSv. Using the prospective technique shows that the dose can be reduced by 47.94% compared with the retrospective technique. The estimated dose was manually calculated based on CTDIvol and DLP, resulting in an effective dose of 33.5 mSv with the retrospective technique and an effective dose of 11.95 mSv with the prospective technique. Using the prospective technique shows that the dose can be reduced by 64.32% compared with the retrospective technique. The rationale for choosing a potential cardiac CT regimen must be careful and precise, as it may not apply to all patients. Use recommendations apply only to patients with low, stable heart rates and less than five bpm variability. Keywords: CT Cardiac, effective dose, Retrospective ECG-Gating, Prospective ECG-Gating.

Coded-Aperture imaging based on random code and Backpropagation neural network

Coded-aperture radiation imaging technology has important application value in the field of space radiation detection. A coded-aperture imaging algorithm based on random code and Backpropagation neural network (BPNN) is proposed for high quality imaging of x-rays and gamma rays in space environments. The experimental results show that BPNN can improve the signal-to-noise ratio of the reconstructed image when applied to the reconstruction process of coded-aperture imaging based on random code. Therefore, it has a good application prospect in the field of space coded-aperture imaging.

Organ-based tube current modulation versus spectral shaping via tin prefiltration: What does bismuth breast shielding add in low-dose lung CT?

PurposeSince organ-based tube current modulation (OBTCM) and tin prefiltration are limited on their own in lowering the dose of lung CT examinations, this experimental study was designed to investigate whether combinations with anterior patient shielding can increase the dose reduction potential. Material and methodsThree pairs of scan protocols without/with breast shield (P1/P2: standard 120kVp, P3/P4: OBTCM at 100 kVp, P5/P6: Sn 100 kVp) were employed for radiation exposure and image quality comparisons on an anthropomorphic Alderson-Rando phantom. Equivalent doses were measured in eleven sites via thermoluminescent dosimetry and the effective dose was obtained by summation of the weighted organ doses. Dose-weighted contrast-to-noise ratios (CNRD) were calculated and four radiologists independently assessed the quality of images generated with each protocol. ResultsWhile no significant difference was determined between standard and OBTCM protocols regardless of breast shield (p ≥ 0.068), equivalent doses with spectral shaping were substantially lower (p ≤ 0.003). The highest effective dose was ascertained for standard scans (P1/P2: 7.3/6.8 mSv) with a dose reduction of 8.0 % via breast shielding. The use of a bismuth shield was more beneficial in OBTCM (P3/P4: 6.6/5.3 mSv) and spectral shaping (P5/P6: 0.7/0.6 mSv), reducing the effective dose by 19.8 % and 13.9 %, respectively. Subjective assessment favoured standard protocol P1 over tin prefiltration low-dose scans (p ≤ 0.032), however, no scan protocol entailed diagnostically insufficient image quality. ConclusionsWhereas breast shielding is particularly beneficial in combination with OBTCM, spectral shaping via tin prefiltration facilitates the most pronounced dose reduction in lung CT imaging with acceptable image quality.