Real-time Radiation Research Articles

Radio-opaque contrast agents for liver cancer targeting with KIM during radiation therapy (ROCK-RT): an observational feasibility study.

This observational study aims to establish the feasibility of using x-ray images of radio-opaque chemoembolisation deposits in patients as a method for real-time image-guided radiation therapy of hepatocellular carcinoma. This study will recruit 50 hepatocellular carcinoma patients who have had or will have stereotactic ablative radiation therapy and have had transarterial chemoembolisation with a radio-opaque agent. X-ray and computed tomography images of the patients will be analysed retrospectively. Additionally, a deep learning method for real-time motion tracking will be developed. We hypothesise that: (i) deep learning software can be developed that will successfully track the contrast agent mass on two thirds of cone beam computed tomography (CBCT) projection and intra-treatment images (ii), the mean and standard deviation (mm) difference in the location of the mass between ground truth and deep learning detection are ≤ 2mm and ≤ 3mm respectively and (iii) statistical modelling of study data will predict tracking success in 85% of trial participants. Developing a real-time tracking method will enable increased targeting accuracy, without the need for additional invasive procedures to implant fiducial markers. Registered to ClinicalTrials.gov (NCT05169177) 12th October 2021.

8096 Optimization of Radiation Safety Release Instructions After Iodine-131 Treatment for Differentiated Thyroid Cancers

Abstract Disclosure: A.H. Smith: None. T. Greist: None. Introduction: Iodine-131 (I-131) is a common therapy for treatment of differentiated thyroid cancers (DTC); however its radioactivity poses a risk to public health. There is wide inter-facility variation in release instructions to minimize incident exposure to other individuals. Isolation measures to reduce gamma exposure may pose harm to an individual's mental or physical health, especially in new parents or patients who require caregivers. Most studies estimating incident exposure utilize cumulative dosimetry to estimate duration of safety release instructions, but this relies on expert assumptions of the clearance of I-131, which is altered in patients who have had their thyroid removed. Measuring real-time longitudinal gamma exposure would optimize recommendations to balance the radiation safety risks with the risks associated with isolation. Objective: Quantify real-time longitudinal incident gamma radiation exposure to others from patients with DTC status post thyroidectomy treated with I-131. Methods: Patients were asked to measure exposure rates at a distance of one meter three times a day for fourteen days, using a portable ion chamber at their homes. Exposure rates over time were used to form an exponential decay model and to estimate the time after which cumulative exposure is below a reasonably low threshold. Results: 32 patients were included in the study. The average effective half-life was 15.8 hours. Exposure readings over time were best fit with an exponential decay model using one decay rate, rather than a model that uses separate extrathyroidal and thyroidal decay rates. Among patients administered less than 114 mCi, cumulative gamma exposure is less than 100 mR after 24 hours of isolation. Between 114 and 163 mCi, cumulative gamma exposure is less than 100 mR after 48 hours of isolation. Conclusion: Cumulative gamma radiation exposure at one meter was found to be low enough to consider re-evaluating isolation protocols and safety release instructions for long-term distancing in patients status post thyroidectomy treated with I-131. Presentation: 6/1/2024

Application of motion prediction based on a long short-term memory network for imaging dose reduction in real-time tumor-tracking radiation therapy

PurposeTo demonstrate the possibility of using a lower imaging rate while maintaining acceptable accuracy by applying motion prediction to minimize the imaging dose in real-time image-guided radiation therapy. MethodsTime-series of three-dimensional internal marker positions obtained from 98 patients in liver stereotactic body radiation therapy were used to train and test the long-short-term memory (LSTM) network. For real-time imaging, the root mean squared error (RMSE) of the prediction on three-dimensional marker position made by LSTM, the residual motion of the target under respiratory-gated irradiation, and irradiation efficiency were evaluated. In the evaluation of the residual motion, the system-specific latency was assumed to be 100 ms. ResultsExcept for outliers in the superior–inferior (SI) direction, the median/maximum values of the RMSE for imaging rates of 7.5, 5.0, and 2.5 frames per second (fps) were 0.8/1.3, 0.9/1.6, and 1.2/2.4 mm, respectively. The median/maximum residual motion in the SI direction at an imaging rate of 15.0 fps without prediction of the marker position, which is a typical clinical setting, was 2.3/3.6 mm. For rates of 7.5, 5.0, and 2.5 fps with prediction, the corresponding values were 2.0/2.6, 2.2/3.3, and 2.4/3.9 mm, respectively. There was no significant difference between the irradiation efficiency with and that without prediction of the marker position. The geometrical accuracy at lower frame rates with prediction applied was superior or comparable to that at 15 fps without prediction. In comparison with the current clinical setting for real-time image-guided radiation therapy, which uses an imaging rate of 15.0 fps without prediction, it may be possible to reduce the imaging dose by half or more. ConclusionsMotion prediction can effectively lower the frame rate and minimize the imaging dose in real-time image-guided radiation therapy.

465: Real-time adaptive radiation therapy for multiple lung targets: a proof-of-concept study

465: Real-time adaptive radiation therapy for multiple lung targets: a proof-of-concept study

Real-Time Radiation Beam Monitoring by Flexible Perovskite Thin Film Arrays.

Real-time and in-line transversal monitoring of ionizing radiation beams is a crucial task for several applications which span from medical treatments to particle accelerators in high energy physics. Here a flexible and large area device based on 2D hybrid perovskite thin films (phenylethylammonium lead bromide), fabricated onto a thin flexible polyimide substrate, able to map the transversal beam profile of high energy radiation beams is reported. The performance of this novel tool is here compared with the one offered by standard commercial large-area technology, namely radiochromic sheets. The great potential of this class of devices is demonstrated by successfully mapping in real-time a 5 MeV proton beam at fluxes between 108 and 1010 H+ s-1 cm-2, confirming the capability to operate in a radiation-harsh environment without output signal saturation issues. The versatility and scalability of here proposed detecting system are demonstrated by the development of a multipixel array able to map in real-time a 40 kVp X-ray beam spot (dose rate 8 mGy s-1). Perovskite thin film-based detectors are thus assessed as a very promising class of thin, flexible devices for real-time, in-line, large-area, conformable, reusable, transparent, and low-cost transversal beam monitoring of different ionizing radiation.

Real time eye dose reduction in fluoroscopy with auditory and visual feedback dosimeter through swine model experiments

This paper proposes measurement and reduction of eye dose in real time for the physician and the assistant performing fluoroscopy guided arterial puncture. Eye dose rates were measured for 30 fluoroscopy-guided punctures of bilateral femoral arteries in pigs. Fifteen fluoroscopy-guided punctures were performed using real time radiation dosimeter without auditory and visual feedback and other fifteen punctures were done using real time radiation dosimeter with visual and auditory feedback worn on forehead by an interventional cardiologist having experience of more than 10 years. The mean radiation dose rate for eyes of physician during arterial puncturing with real time radiation dosimeter with auditory feedback was 0.07 mSv/h (n = 15) whereas it was 0.18 mSv/h (n = 15) without visual and auditory feedback. The percentage of reduction with the device was 61% for eyes. In case of assistant the reduction was 33% for eyes (n = 15). The real time visual and auditory feedback dosimeter has reduced the eye dose rate of the physician and assistant and also helped him staying away from the X-ray source. Real time radiation dosimeters can be an effective tool to measure and reduce the dose to the eyes. The radiation eye dose rate for physician and assistant was significantly reduced by using real time radiation dosimeter with visual and auditory feedback. The real time radiation dosimeter not only helps in measuring but also help in minimizing the radiation dose rate for the physician and assistant in real time.

Autonomous Thermal Modulator Based on Gold Film‐Coated Liquid Crystal Elastsomer

AbstractRadiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a “low thermal resistance” state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a “high thermal resistance” state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort.

Single institution experience of MRI-guided radiotherapy for thoracic tumors and clinical characteristics impacting treatment duty cycle.

MRI-guided radiotherapy (MRgRT) allows for direct motion management and real-time radiation treatment plan adaptation. We report our institutional experience using low strength 0.35T MRgRT for thoracic malignancies, and evaluate changes in treatment duty cycle between first and final MRgRT fractions. All patients with intrathoracic tumors treated with MRgRT were included. The primary reason for MRgRT (adjacent organ at risk [OAR] vs. motion management [MM] vs. other) was recorded. Tumor location was classified as central (within 2cm of tracheobronchial tree) vs. non-central, and further classified by the Expanded HILUS grouping. Gross tumor volume (GTV) motion, planning target volume expansions, dose/fractionation, treatment plan time, and total delivery time were extracted from the treatment planning system. Treatment plan time was defined as the time for beam delivery, including multileaf collimator (MLC) motion, and gantry rotation. Treatment delivery time was defined as the time from beam on to completion of treatment, including treatment plan time and patient respiratory breath holds. Duty cycle was calculated as treatment plan time/treatment delivery time. Duty cycles were compared between first and final fraction using a two-sample t-test. Twenty-seven patients with thoracic tumors (16 non-small cell lung cancer and 11 thoracic metastases) were treated with MRgRT between 12/2021 and 06/2023. Fifteen patients received MRgRT due to OAR and 11 patients received MRgRT for motion management. 11 patients had central tumors and all were treated with MRgRT due to OAR risk. The median dose/fractionation was 50 Gy/5 fractions. For patients treated due to OAR (n=15), 80% had at least 1 adapted fraction during their course of radiotherapy. There was no plan adaptation for patients treated due to motion management (n=11). Mean GTV motion was significantly higher for patients treated due to motion management compared to OAR (16.1mm vs. 6.5mm, p=0.011). Mean duty cycle for fraction 1 was 54.2% compared to 62.1% with final fraction (p=0.004). Mean fraction 1 duty cycle was higher for patients treated due to OAR compared to patients treated for MM (61% vs. 45.0%, p=0.012). Duty cycle improved from first fraction to final fraction possibly due to patient familiarity with treatment. Duty cycle was improved for patients treated due to OAR risk, likely due to more central location and thus decreased target motion.

Experimental and simulation study on the thermoelectric performance of semi-transparent crystalline silicon photovoltaic curtain walls

This study aims to evaluate and optimize the thermoelectric performance of semi-transparent crystalline silicon photovoltaic (PV) curtain walls. An integrated thermoelectric performance coupling calculation model was developed, combining heat transfer and electricity generation calculations as a novel approach. Simulations and experiments were conducted to compare the performance of PV curtain walls with conventional curtain walls under various weather conditions, and were validated by experimental data. The results demonstrate that PV curtain walls enhance the thermal environment inside buildings and promote efficient power generation, with the arrangement of PV cells notably affecting performance. Under sunny conditions, the temperatures of the PV cell backplate and glass part backsheet in semi-transparent PV curtain walls exceeded those in ordinary glass curtain walls, yet the indoor air temperature was lower. Furthermore, when the working temperature of PV cells reaches to a certain level, it slightly deviates the electricity generation trend from the real-time solar radiation trend. Under cloudy conditions, the backsheet temperatures of semi-transparent PV curtain walls and standard glass curtain walls align with outdoor temperatures. Different PV module forms demonstrated that striped and square PV module forms offer better lighting effects than whole forms. The working temperatures among the three were close, with an annual average temperature difference of less than 1 °C and a peak temperature difference of approximately 3 °C, impacting the monthly total power generation by less than 1 %. This study presents a more precise and thorough approach for evaluating semi-transparent PV curtain walls' performance, providing insights for future sustainable architectural design.

Techno-Economic Performance and Sensitivity Analysis of an Off-Grid Renewable Energy-Based Hybrid System: A Case Study of Kuakata, Bangladesh

Hybrid renewable energy sources (HRES) are increasingly being utilized to meet global energy demands, particularly in rural areas that rely on diesel generators and are disconnected from the utility grid, due to their environmental and human health benefits. This study investigates the performance of an off-grid, hybrid PV/diesel generator/battery system for a decentralized power plant in Kuakata, Bangladesh, meeting a load demand of 3000 kWh/day with a 501.61 kW peak load demand. HOMER Pro (hybrid optimization model for electric renewable) software (version 3.11) was used to simulate and optimize system operations utilizing real-time solar radiation and load profile data from that location. This study also includes a sensitivity analysis of the off-grid HRES system under different electrical load demands, project longevity, and derating variables. The results reveal that CO2 emissions have potentially decreased by more than 30% and over 10 tons per year, respectively, when compared to traditional power plants. The optimized system’s net present cost (NPC) was determined to be around USD 5.19 million, with a cost of energy (COE) of USD 0.367 per kWh per unit with a 100% renewable component. Furthermore, the current study’s findings are compared to previous research that has resulted in an economical hybrid renewable energy system with an affordable COE. The hybrid energy system under consideration might also be applicable to other parts of the world with comparable climate conditions.

Development of a digital star-shot analysis system for comparing radiation and imaging isocenters of proton treatment machine.

To directly compare the radiation and imaging isocenters of a proton treatment machine, we developed and evaluated a real-time radiation isocenter verification system. The system consists of a plastic scintillator (PI-200, Mitsubishi Chemical Corporation, Tokyo, Japan), an acrylic phantom, a steel ball on the detachable plate, Raspberry Pi 4 (Raspberry Pi Foundation, London, UK) with camera module, and analysis software implemented through a Python-based graphical user interface (GUI). After kV imaging alignment of the steel ball, the imaging isocenter defined as the position of the steel ball was extracted from the optical image. The proton star-shot was obtained by optical camera because the scintillator converted proton beam into visible light. Then the software computed both the minimum circle radius and the radiation isocenter position from the star-shot. And the deviation between the imaging isocenter and radiation isocenter was calculated. We compared our results with measurements obtained by Gafchromic EBT3 film (Ashland, NJ, USA). The minimum circle radii were averaged 0.29 and 0.41mm while the position deviations from the radiation isocenter to the laser marker were averaged 0.99 and 1.07mm, for our system and EBT3 film, respectively. Furthermore, the average position difference between the radiation isocenter and imaging isocenter was 0.27mm for our system. Our system reduced analysis time by 10min. Our system provided automated star-shot analysis with sufficient accuracy, and it is cost-effective alternative to conventional film-based method for radiation isocenter verification.

Assessing and improving radiation safety in cardiac catheterization: a study from Cairo University Hospital

BackgroundCatheter laboratories are high-radiation exposure environments, especially during X-ray procedures like percutaneous transluminal coronary angioplasty and electrophysiological studies. Radiation exposure poses risks of stochastic (e.g., cancer) and deterministic (e.g., skin changes) effects. This study assessed radiation safety and health practices in a cardiac catheterization unit to optimize radiation safety. A cross-sectional study in Cairo University Hospital (March–September 2019) evaluated 700 patients and healthcare workers. Real-time radiation measurements, educational lectures, and radiation protection measures were implemented in three phases. Data on radiation exposure, procedures, and compliance were collected and analyzed.ResultsThe total procedure time and fluoroscopy time per cardiologist did not significantly differ between phases, but there was a statistically significant reduction in the mean total cumulative radiation doses between Phase I and Phase III for cardiologists (P = 0.013). Among nurses and technicians, there was no significant difference in radiation doses between the two phases. Significant correlations were found between operators' radiation doses, procedure time, and fluoroscopy time. Patients' radiation doses decreased significantly from Phase I to Phase III, with correlations between dose, procedure time, and gender. Compliance with radiation protection measures was suboptimal.ConclusionsCompliance with radiation safety standards in the cardiac catheterization unit at the Cairo University Hospital needs improvement. The study highlights the importance of adhering to radiation safety principles and optimizing protective measures to reduce radiation exposure for both patients and healthcare personnel. Despite low compliance, significant reductions in radiation doses were achieved with increased awareness and adherence to specific protection measures. Future efforts should focus on enhancing radiation safety protocols and organ-specific radiation impact assessments.

Deep inspiration breath hold real-time tumor-tracking radiation therapy (DBRT) as a novel stereotactic body radiation therapy approach for lung tumors

Radiotherapy with deep inspiration breath hold (DIBH) reduces doses to the lungs and organs at risk. The stability of breath holding and reproducibility of tumor location are higher during expiration than during inspiration; therefore, we developed an irradiation method combining DIBH and real-time tumor-tracking radiotherapy (RTRT) (DBRT). Nine patients were enrolled in this study. Fiducial markers were placed near tumors using bronchoscopy. Treatment planning computed tomography (CT) was performed thrice during DIBH, assisted by spirometer-based device. Each CT scan was fused using fiducial markers. Gross tumor volume (GTV) was contoured for each dataset and summed to create GTVsum; adding a 5-mm margin around GTVsum generated the planning target volume. The prescribed dose was mainly 42 Gy in four fractions. The treatment plan was created using DIBH CT (DBRT-plan), with a similar treatment plan created for expiratory CT for cases for which DBRT could not be performed (conv-plan). Vx defined as the volume of the lung received x Gy, and the mean lung dose, V20, V10, and V5 were evaluated. DBRT was completed in all patients. Mean dose, V20, and V10 were significantly lower in the DBRT-plan than in the conv-plan (all p = 0.003). Mean rates of decrease for mean dose, V20, and V10 were 14.0%, 27.6%, and 19.1%, respectively. No significant difference was observed in V5. We developed DBRT, a stereotactic body radiation therapy performed with the DIBH technique; it combines a spirometer-based breath-hold support system with an RTRT system. All patients who underwent DBRT completed the procedure without any technical or mechanical complications. This is a promising methodology that may significantly reduce lung doses.

Radiation dose to multidisciplinary staff members during complex interventional procedures

IntroductionComplex interventional radiology procedures involve extensive fluoroscopy and image acquisition while staff are in-room. Monitoring occupational radiation dose is crucial in optimization. The purpose was to determine radiation doses received by staff involved in complex interventional procedures performed in a dedicated vascular or neuro intervention room. MethodsIndividual real-time radiation dose for all staff involved in vascular and neuro-interventional procedures in adult patients was recorded over a one-year period using wireless electronic dosimeters attached to the apron thyroid shield. A reference dosimeter was attached to the C-arm near the tube housing to measure scattered, unshielded radiation. Radiology staff carried shoulder thermo-luminescent dosimeters with monthly read-out to monitor dose over time. ResultsOccupational radiation dose was measured in 99 interventional procedures. In many cases prostate artery embolization procedures exposed radiologists to high radiation doses with a median of 15.0 μSv and a very large spread, i.e. 0.2–152.5 μSv. In all procedures except uterine fibroid embolization radiographers were exposed to lower doses than those of radiologists, with endovascular aortic repair being the procedure with highest median exposure to assisting radiographers, i.e. 2.2 μSv ranging from 0.1 to 36.1 μSv. Median radiation dose for the reference dosimeter was 670 μGy while median staff dose for all procedures combined was 3.2 μGy. ConclusionRadiation doses for multiple staff were determined and the ratio between staff dose and reference dosimeter indicated proper use of shielding in general. Some high-dose procedures may need further optimization for certain staff members, especially those not primarily employed in radiology. Implications for practiceThe study provides benchmark doses that may be used widely in audits and in the ongoing effort to optimize radiation protection for staff in interventional radiology.

Development and characterisation of a plastic scintillator dosemeter in high-energy photon beams.

The radioluminescent (RL) dosemeter is excellent for real-time radiation measurement and can be used in various applications. A plastic scintillator is often the choice sensor because of its size and tissue equivalency. This study aims to characterise a novel plastic scintillator irradiated with high-energy photon beams. An RL dosimetry system was developed using the plastic scintillator. The RL dosimetry system was irradiated using a linear accelerator to characterise the dose linearity, dose rate, energy dependency and depth dose. The developed system showed a linear response toward the dose and dose rate. An energy dependency factor of 1.06 was observed. Depth dose measurement showed a mean deviation of 1.21% from the treatment planning system. The response and characteristics of the plastic scintillator show that it may be used as an alternative in an RL dosimetry system.

Real-time radiation monitoring of high energy 1.2-GeV synchrotron accelerator using experimental physics and industrial control system

The high energy 1.2-GeV electron accelerator facility’s radiation detection and monitoring system (RDMS) has greatly evolved to be the effective backbone of real-time radiation monitoring for the new light source 3-GeV synchrotron facility. Experimental Physics and Industrial Control System (EPICS), ethernet hardware connections (Optic fibers), and Web-based software interfaces make up the new RDMS framework, built on well-liked network technology. The problems of monitoring i.e., a lot of manpower, poor monitoring accuracy, and inability to monitor continuously in the high radiation dose are eliminated. EPICS, composed of an Input/Output Controller (IOC) and Client Workstations which can communicate with a Local Area Network (LAN), were applied for remote control and radiation measurement. EPICS has been able to transport and store massive amounts of data for large-scale systems with a wide range and high accuracy. The monitoring data were sent to the server through the optic fibers network system, which is more advantages such as no distance restrictions, low attenuation of the signal, faster responding times, and particularly electromagnetic resistance. The data can be accessed anywhere from client monitors with graphical user interfaces. This system is successfully developed and tested for the high energy 1.2-GeV electron accelerator. The RDMS is useful for radiation safety to monitor the radiation dose level during machine operation to protect occupational workers and the public from radiation hazards.

MRI-guided Pelvic Radiation Therapy: A Primer for Radiologists.

Radiation therapy (RT) is a core pillar of oncologic treatment, and half of all patients with cancer receive this therapy as a curative or palliative treatment. The recent integration of MRI into the RT workflow has led to the advent of MRI-guided RT (MRIgRT). Using MRI rather than CT has clear advantages for guiding RT to pelvic tumors, including superior soft-tissue contrast, improved organ motion visualization, and the potential to image tumor phenotypic characteristics to identify the most aggressive or treatment-resistant areas, which can be targeted with a more focal higher radiation dose. Radiologists should be familiar with the potential uses of MRI in planning pelvic RT; the various RT techniques used, such as brachytherapy and external beam RT; and the impact of MRIgRT on treatment paradigms. Current clinical experience with and the evidence base for MRIgRT in the settings of prostate, cervical, and bladder cancer are discussed, and examples of treated cases are illustrated. In addition, the benefits of MRIgRT, such as real-time online adaptation of RT (during treatment) and interfraction and/or intrafraction adaptation to organ motion, as well as how MRIgRT can decrease toxic effects and improve oncologic outcomes, are highlighted. MRIgRT is particularly beneficial for treating mobile pelvic structures, and real-time adaptive RT for tumors can be achieved by using advanced MRI-guided linear accelerator systems to spare organs at risk. Future opportunities for development of biologically driven adapted RT with use of functional MRI sequences and radiogenomic approaches also are outlined. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

ANALISIS PAPARAN RADIASI SKYSHINE DINDING RUANGAN ANGIOGRAFI/CATHLAB RUMAH SAKIT MITRA KELUARGA KEMAYORAN BERSUDUT GANTRY 0 DERAJAT

Based on NCRP (2005), skyshine radiation generally occurs in radiotherapy facilities, the cause of which is that some radiation facilities are designed with minimal shielding on the linear accelerator (Linac) ceiling. As time goes by, Skyshine radiation monitoring is not only focused on radiotherapy facilities, but radiodiagnostic facilities also need to be monitored, especially interventional radiology, which uses real-time X-ray radiation at certain times. Regarding this matter, it is necessary to check whether the walls of the existing angiography room or cath lab are protected from skyshine radiation. This study aims to determine whether the Angiography/Cathlab room at Mitra Keluarga Kemayoran Hospital does not produce skyshine radiation. The method for measuring skyshine radiation exposure uses a survey meter at a distance of 30 cm and 2 meters 3 times from the outer wall of the Angiography/Cathlab room on the north, south, and west sides of the gantry; then the gantry is positioned at 0 degree. The research results show that radiation exposure is 0.14 µSv/hour at a distance of 30 cm. Skyshine radiation was detected at a distance of 2 meters with an exposure value of 0.32 µSv/hour on the west side of the gantry and 0.39 µSv/hour on the north side of the gantry, this occurred due to the radiation barrier wall (Pb ) not complete until the ceiling is only 2 meters high from the floor. The conclusion is that the walls of the Angiography/Cathlab room at Mitra Keluarga Kemayoran Hospital have exposure to skyshine radiation at a distance of 2 meters measured from the outer walls of the Angiography/Cathlab room on the west and north sides of the gantry of 0.32 µSv/hour and 0.39 µSv/hour. Keywords: angiography/cath lab, radiation, X-ray, skyshine, interventional radiology.

Pseudo CT Synthesis Using Cone-Beam CT of Cervical Cancer with GAN-Based Neural Network Model

Cervical cancer (CC) is a tumor disease that threatens the health of women. As an important treatment of CC, radiotherapy has been widely used in clinic. With the rapid development of radiotherapy technology, adaptive radiotherapy has received much attention. Adaptive radiotherapy means more accurate radiation dose and more accurate radiation area, which can effectively protect normal tissue. It is significant to improve the local control rate of tumor and the quality of life of patients. However, the Cone-Beam CT (CBCT) images collected during radiotherapy are of poor quality and cannot provide real-time radiation effect information, resulting in timely and effective adjustment of radiation dose and radiation area in the process of radiotherapy for cervical cancer. To alleviate this issue, this study will establish a model to leverage CC CBCT images to synthetize pseudo computed tomography (CT) images with high quality, so as to achieve the purpose of quality improvement. This study included the data of 20 patients with CC in ** hospital. The planning CT and CBCT scan data of each patient before radiotherapy were collected, and the interval between the two kinds of image data was required to be less than one week. After data preprocessing, a total of 1206 pairs of images were trained and tested. The generative adversarial network (GAN) is constructed. In order to ensure the similarity between the input image and the output image, the L1 loss function is leveraged. And the full supervision method is used to train the model to achieve a better effect of image synthesis and improve the quality of CBCT image. Peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) were used as evaluation indexes. Using five-fold cross-validation, the values of PSNR between the pseudo-CT (sCT) and the planning CT (pCT) image and between the CBCT and the pCT image are calculated. The results are 26.9 and 22.6, respectively. The sCT obtained from the GAN model increases the peak signal-to-noise ratio by 19% compared with the original CBCT, which means that the proposed model built in this study can improve the useful information of the CBCT image. The SSIM values between sCT and pCT and between CBCT and pCT are also calculated, and the average values of them are 0.89 and 0.63, respectively. Therefore, in this experiment, the structure of the sCT obtained by the proposed model is closer to pCT. And the SSIM increases by 41.2% compared with the original CBCT, which means that the sCT by the proposed model is more similar to the pCT in structure. These results could make a more accurate judgment on the effect of radiotherapy. In this study, the pseudo-CT synthesis method based on GAN can improve the quality of CC CBCT image. The results show this method makes the structure clearer and could assist doctors to adjust the radiation dose and radiation area in time. This study is able to facilitate the development of adaptive radiotherapy for CC.

DEVELOPMENT OF AN IOT DEVICE BASED ON A GEIGER COUNTER

The threat of radiation exposure is always present in modern world. In recent years, this threat has become even more pronounced due to Russian aggression on Ukrainian territory. Therefore, the need for remote data collection and analysis of radiation background information has become even more important, and research in the field of creating small, low-cost devices that can monitor radiation levels of a certain area in real-time and provide information to local government agencies responsible for the safety of populated areas can be considered relevant. Radiation background level monitoring is essential to ensuring that people are informed of any potential threats to their health. It is proposed to develop a dense network of monitoring stations that can collect and transmit data about background radiation in real time. Measurement results will be processed and stored on a resource that is available to both local authorities and public. The Message Queue Telemetry Transport (MQTT) protocol is used to transmit information, as it is durable, lightweight, and efficient. A hardware and software system for collecting and transmitting radioactivity values has been developed. The system is based on a module with Geiger counter tube, which is used to measure the level of radiation in the area. The module is connected to a microcontroller, which processes the data and transmits it to a central server. To summarize and process the measurement results, the Majordomo broker is used. It is installed on a remotely accessible network storage. In conclusion, the proposed system can ensure the safety of the public, allowing authorities, experts and trained personnel to quickly and efficiently respond to any potential radiation threats, protecting people from radiation exposure.