Effect of simultaneous integrated boost concepts on photoneutron and distant out-of-field doses in VMAT for prostate cancer.

BACKGROUND: A simultaneous integrated boost (SIB) may result in increased out-of-field (DOOF) and photoneutron (HPN) doses in volumetric modulated arc therapy (VMAT) for prostate cancer (PCA). This work therefore aimed to compare DOOF and HPN in flattened (FLAT) and flattening filter-free (FFF) 6­MV and 10-MV VMAT treatment plans with and without SIB. METHODS: Eight groups of 30 VMAT plans for PCA with 6 MV or 10 MV, with or without FF and with uniform (2 Gy) or SIB target dose (2.5/3.0 Gy) prescriptions (CONV, SIB), were generated. All 240 plans were delivered on a slab-phantom and compared with respect to measured DOOF and HPN in 61.8 cm distance from the isocenter. The 6­ and 10-MV flattened VMAT plans with conventional fractionation (6- and 10-MV FLAT CONV) served as standard reference groups. Doses were analyzed as a function of delivered monitor units (MU) and weighted equivalent square field size Aeq. Pearson's correlation coefficients between the presented quantities were determined. RESULTS: The SIB plans resulted in decreased HPN over an entire prostate RT treatment course (10-MV SIB vs. CONV -38.2%). Omission of the flattening filter yielded less HPN (10-MV CONV -17.2%; 10-MV SIB -22.5%). The SIB decreased DOOF likewise by 39% for all given scenarios, while the FFF mode reduced DOOF on average by 60%. A strong Pearson correlation was found between MU and HPN (r > 0.9) as well as DOOF (0.7 < r < 0.9). CONCLUSION: For a complete treatment, SIB reduces both photoneutron and OOF doses to almost the same extent as FFF deliveries. It is recommended to apply moderately hypofractionated 6­MV SIB FFF-VMAT when considering photoneutron or OOF doses.

A phantom study of a protective trolley for neonatal radiographic imaging: new equipment to protect the operator from scatter radiation.

Chest radiography is commonly performed as a diagnostic tool of neonatal diseases. Contact-based radiation personal protective equipment (RPPE) has been widely used for radiation protection, but it does not provide full body protection and it is often shared between users, which has become a major concern during the coronavirus disease 2019 (COVID-19) pandemic. To address these issues, we developed a novel trolley to protect radiographers against X-ray radiation by reducing scatter radiation during neonatal radiographic examinations. We measured the scatter radiation doses from a standard neonatal chest radiograph to the radiosensitive organs using a phantom operator in three protection scenarios (trolley, radiation personal protective equipment [RPPE], no protection) and at three distances. The results showed that the scatter radiation surface doses were significantly reduced when using the trolley compared with RPPE and with no protection at a short distance (P<0.05 for both scenarios in all radiosensitive organs). The novel protective trolley provides a non-contact protective tool for radiographers against the hazard of scatter radiation during neonatal radiography examinations.

[Scatter Radiation Intensities during Transforaminal Lumbar Interbody Fusion Using a Mobile C-arm System].

The purpose of this study was to measure the scatter radiation intensity during transforaminal lumbar interbody fusion using a mobile C-arm system (Arcadis Orbic 3D; Siemens) and minimize radiation exposure. Dosimetry was performed with anterior-posterior and lateral continuous fluoroscopy, and cone beam computed tomography (CT). A scaffold tower (L: 300 cm×W: 200 cm×H: 150 cm) was built with radiation-resistant paper cylinders at intervals of 50 cm and plastic joints over the bed, and 100 optically stimulated luminescence dosimeters (nanoDot; Nagase Landauer) were placed on each joint. A human torso phantom from head to pelvis (Kyoto Kagaku) was positioned on the bed in a prone position. The scatter radiation dose in a lateral view was highest on the X-ray tube side at the height of 100 cm (170.5 µGy/min). The scatter radiation dose increased significantly on the X-ray tube side during lateral continuous fluoroscopy. Continuous change of surgeons' standing positions is important to minimize radiation exposure received by a specific surgeon.

Assessment of scatter radiation dose and absorbed doses in eye lens and thyroid gland during digital breast tomosynthesis.

Digital breast tomosynthesis (DBT) is an alternative tool for breast cancer screening; however, the magnitude of peripheral organs dose is not well known. This study aimed to measure scattered dose and estimate organ dose during mammography under conventional (CM) and Tomo (TM) modes in a specific DBT system. Optically stimulated luminescence dosimeters (OSLDs), whose responses were corrected using a parallel-plate ionization chamber, were pasted on the surface of custom-made polymethyl methacrylate (PMMA) and RANDO phantoms to measure entrance surface air kerma (ESAK). ESAK measurements were also acquired with a 4.5-cm thick breast phantom for a standard mammogram. Organ dose conversion factors (CFD ) were determined as ratio of air kerma at a specific depth to that at the surface for the PMMA phantom and multiplied by the ratio of mass energy absorption coefficients of tissue to air. Normalized eye lens and thyroid gland doses were calculated using the RANDO phantom by multiplying CFD and ESAK values. Maximum variability in OSLD response to scatter radiation from the DBT system was 33% in the W/Rh spectrum and variations in scattered dose distribution were observed between CM and TM. The CFD values for eye lens and thyroid gland ranged between 0.58 to 0.66 and 0.29 to 0.33, respectively. Mean organ doses for two-view unilateral imaging were 0.24 (CM) and 0.18 (TM) µGy/mAs for the eye lens and 0.24 (CM) and 0.25 (TM) µGy/mAs for the thyroid gland. Higher organ doses were observed during TM compared to CM as the automatic exposure control (AEC) system resulted in greater total mAs values in TM.

Quantification of scatter radiation from radiographic procedures in a neonatal intensive care unit.

BACKGROUND: In a neonatal intensive care unit (NICU), preterm infants are often exposed to a large number of radiographic examinations, which could cause adjacent neonates, family caregivers and staff members to be exposed to a dose amount due to scatter radiation. OBJECTIVE: To provide information on scatter radiation exposure levels in a NICU, to compare these values with the effective dose limits established by the European Union and to evaluate the effectiveness of radiation protection devices in this setting. MATERIALS AND METHODS: Radiation exposure levels due to scatter radiation were estimated by passive detectors (thermoluminescent dosimeters) and direct dosimetric measurements (with a dose rate meter); in the latter case, an angular map of the scatter dose distribution was achieved. RESULTS: The dose due to scatter radiation to staff in our setting is approximately 160 µSv/year, which is markedly lower than the effective dose limit for workers established by the European Union (20 mSv/year). The doses range between 0.012 and 0.095 µSv/radiograph. Considering a mean hospitalization period of 3 months and our NICU workload, the corresponding scatter radiation dose to an adjacent patient and/or his/her caregiver is at most 40 µSv. CONCLUSION: For distances greater than 1 m from the irradiation field, both scatter dose absorbed by a staff member during a year and that by an adjacent patient and/or his/her caregiver during hospitalization is less than 1 mSv, which is the exposure limit for public members in a year.

Electrometer offset current due to scattered radiation.

Relative dose measurements with small ionization chambers in combination with an electrometer placed in the treatment room ("internal electrometer") show a large dependence on the polarity used. While this was observed previously for percent depth dose curves (PDDs), the effect has not been understood or preventable. To investigate the polarity dependence of internal electrometers used in conjunction with a small-volume ionization chamber, we placed an internal electrometer at a distance of 1 m from the isocenter and exposed it to different amounts of scattered radiation by varying the field size. We identified irradiation of the electrometer to cause a current of approximately -1 pA, regardless of the sign of the biasing voltage. For low-sensitivity detectors, such a current noticeably distorts relative dose measurements. To demonstrate how the current systematically changes PDDs, we collected measurements with nine ionization chambers of different volumes. As the chamber volume decreased, signal ratios at 20 and 10 cm depth (M20/M10) became smaller for positive bias voltage and larger for negative bias voltage. At the size of the iba CC04 (40 mm³) the difference of M20/M10 was around 1% and for the smallest studied chamber, the iba CC003 chamber (3 mm³), around 7% for a 10 × 10 cm² field. When the electrometer was moved further from the source or shielded, the additional current decreased. Consequently, PDDs at both polarities were brought into alignment at depth even for the 3 mm³ ionization chamber. The apparent polarity effect on PDDs and lateral beam profiles was reduced considerably by shielding the electrometer. Due to normalization the effect on output values was low. When measurements with a low-sensitivity probe are carried out in conjunction with an internal electrometer, we recommend careful monitoring of the particular setup by testing both polarities, and if deemed necessary, we suggest shielding the electrometer.

Real-time, ray casting-based scatter dose estimation for c-arm x-ray system.

OBJECTIVES: Dosimetric control of staff exposure during interventional procedures under fluoroscopy is of high relevance. In this paper, a novel ray casting approximation of radiation transport is presented and the potential and limitation vs. a full Monte Carlo transport and dose measurements are discussed. METHOD: The x-ray source of a Siemens Axiom Artix C-arm is modeled by a virtual source model using single Gaussian-shaped source. A Geant4-based Monte Carlo simulation determines the radiation transport from the source to compute scatter from the patient, the table, the ceiling and the floor. A phase space around these scatterers stores all photon information. Only those photons are traced that hit a surface of phantom that represents medical staff in the treatment room, no indirect scattering is considered; and a complete dose deposition on the surface is calculated. To evaluate the accuracy of the approximation, both experimental measurements using Thermoluminescent dosimeters (TLDs) and a Geant4-based Monte Carlo simulation of dose depositing for different tube angulations of the C-arm from cranial-caudal angle 0° and from LAO (Left Anterior Oblique) 0°-90° are realized. Since the measurements were performed on both sides of the table, using the symmetry of the setup, RAO (Right Anterior Oblique) measurements were not necessary. RESULTS: The Geant4-Monte Carlo simulation agreed within 3% with the measured data, which is within the accuracy of measurement and simulation. The ray casting approximation has been compared to TLD measurements and the achieved percentage difference was -7% for data from tube angulations 45°-90° and -29% from tube angulations 0°-45° on the side of the x-ray source, whereas on the opposite side of the x-ray source, the difference was -83.8% and -75%, respectively. Ray casting approximation for only LAO 90° was compared to a Monte Carlo simulation, where the percentage differences were between 0.5-3% on the side of the x-ray source where the highest dose usually detected was mainly from primary scattering (photons), whereas percentage differences between 2.8-20% are found on the side opposite to the x-ray source, where the lowest doses were detected. Dose calculation time of our approach was 0.85 seconds. CONCLUSION: The proposed approach yields a fast scatter dose estimation where we could run the Monte Carlo simulation only once for each x-ray tube angulation to get the Phase Space Files (PSF) for being used later by our ray casting approach to calculate the dose from only photons which will hit an movable elliptical cylinder shaped phantom and getting an output file for the positions of those hits to be used for visualizing the scatter dose propagation on the phantom surface. With dose calculation times of less than one second, we are saving much time compared to using a Monte Carlo simulation instead. With our approach, larger deviations occur only in regions with very low doses, whereas it provides a high precision in high-dose regions.

Investigation of Scattered Radiation Reduction Effect by Use of Collimator Cover Covered with Leaded Sheet in Angiography Equipment.

The purpose of this study was to investigate the effect of scattered radiation reduction to medical staff by attaching the leaded sheet on the collimator cover of the angiography equipment. Ambient dose equivalent was measured to compare the rate of scattered radiation reduction between with and without the leaded sheet. Shielding effect was confirmed for scattered radiation in all directions, especially 27% of shielding ratio in the head and neck area when angiography equipment installed with small detector, and more than 40% of shielding ratio when adjusting a cut portion of leaded sheet to the field size. However, it decreased when the dose area product meter was not attached. Therefore, our proposed leaded sheet can reduce radiation dose to medical staff during angiographic and interventional procedures.

JOURNAL CLUB: Scatter Radiation Dose From Digital Screening Mammography Measured in a Representative Patient Population.

OBJECTIVE: The purpose of this study was to quantify the amount of scatter radiation received at the skin surface overlying the thyroid gland, salivary gland, lens of the eye, sternum, and uterus during a routine screening digital mammographic examination measured in a representative patient population. SUBJECTS AND METHODS: The subjects were 207 women without symptoms with varied body mass indexes who underwent annual screening mammography while wearing six optically stimulated luminescence dosimeters placed at the bridge of the nose, right submandibular gland, right and left thyroid lobes, mid sternum, and 2 cm caudal to the umbilicus to assess scatter radiation dose to the skin. RESULTS: The average scatter radiation doses at the skin surface during digital screening mammography in the representative population of women were as follows: overlying the right lobe of the thyroid, 0.24 mGy; left lobe of the thyroid, 0.25 mGy; salivary gland, 0.2 mGy; bridge of the nose, 0.025 mGy; sternum, 0.87 mGy; and umbilicus, 0.011 mGy. The scatter radiation doses at the umbilicus and the bridge of the nose were too low to measure with statistical confidence. Scatter radiation dose increased with increasing body mass index and increasing breast compression thickness. CONCLUSION: Scatter radiation dose at the skin overlying organs of interest is a small fraction of the entrance skin dose to the breast. The low levels of scatter radiation measured do not support delaying clinically indicated mammography during early pregnancy.

Assessment of the Occupational Radiation Dose from a Handheld Portable X-ray Unit During Full-mouth Intraoral Dental Radiographs in the Dog and the Cat - A Pilot Study.

Occupational radiation protection is an important consideration in small animal clinics world-wide. With the increased use of portable handheld X-ray devices in veterinary dentistry, concerns related to occupational radiation protection are being raised. Annual occupational dose limits for dental workers are expressed as Total Dose Equivalent (TDE) or Effective Dose. The permitted TDE can vary depending on the anatomical region, ranging from 50 millisieverts (mSv) for the external whole body exposure dose to 500 mSv for external exposure of the skin or an extremity. Although several studies have been performed in human dentistry to establish the amount of backscatter radiation produced using portable handheld X-ray devices, no similar research has been conducted in veterinary dentistry. This study aimed to determine the TDE while acquiring a full mouth intraoral radiograph set in dogs and cats and to estimate the TDE for a handheld X-ray device's operator. For this, the backscatter radiation dose recorded by three sets of monitoring dosimeters located in strategic anatomical areas of the operator was assessed after taking one hundred intraoral radiographs in each group. The study concluded that the backscatter radiation levels were far below the permitted annual occupational doses in the three patient groups of this study. Even though the portable handheld X-ray unit was demonstrated to be a safe dental radiographic unit regarding backscattering radiation, the operator's eye, ovary, and breast regions were exposed to unnecessary radiation.

Investigation of scatter radiation intensities in the cardiac catheter laboratory: novel versus traditional shielding solutions.

A manufacturer has released a novel shielding solution (NSS): Rampart M1128 and claimed that the personal protective equipment (PPE) can be removed. This study investigates the scatter intensities with the NSS or the traditional shielding solutions (TSS) including the ceiling-suspended screen and the tableside lead drape. Isodose maps were generated by two series of measurements with an anthropomorphic phantom using NSS and TSS. Three survey meters were positioned at different heights to measure the scatter intensities at the eye, chest, and pelvic levels. Additional measurements were made at the primary and secondary operators? locations to evaluate the scatter intensities with different clinical projections. For the main operator positions, the isodose maps showed that NSS could result in a scatter dose that reduced by 80% to 95% compared to the same positions with TSS at the eye and chest levels. The corresponding result at the pelvic level was a reduction of 50%. These reductions should be compared to the additional protection by PPE: up to 80% reduction from lead eyeglasses and up to 95% from protective garments. Considering both operators at clinically relevant LAO projections, NSS resulted in scatter dose that was 80% to 96%, 76% to 96% and 25% to 60% lower than those of the TSS at eye, chest and pelvis levels. The protection of NSS is comparable with that of TSS alongside PPE at the eye but not at the chest and the pelvic levels under the setup of coronary angiography.

Evaluation of novel radiation protection devices during radiologically guided interventions.

BACKGROUND: In radiologically guided interventions, medical practitioners are subjected to radiation exposure, which may lead to radiation-induced diseases. In this study, novel radiation shields for the head and neck were evaluated for their potential to reduce radiation exposure. METHOD: An anthropomorphic phantom was exposed on its left side to scattered radiation from beneath to simulate the exposure of an operator in a x-ray operating room. Thermoluminescent dosimeters (TLDs) were positioned at different depths in five slices in the phantom, measuring personal dose equivalent. Two different set up situations were evaluated: a head protector designed to reduce radiation in the upper section of the head; and a novel thyroid protector prototype extended in the front and on both sides, designed to reduce radiation in the lower and middle sections of the head. A standard thyroid collar prototype and a ceiling mounted lead glass shield were used as comparisons. Furthermore, the head protector was evaluated in a clinical study in which TLDs were positioned to measure scattered radiation exposure to the heads of operators during endovascular interventions. RESULTS: The extended thyroid protector reduced the scattered radiation in the throat, chin, and ear slices. Some shielding effect was seen in the brain and skull slices. The head protector showed a shielding effect in the skull slice up to two cm depth where it covered the phantom head. As expected, the ceiling mounted lead glass shield reduced the scattered radiation in all measuring points. CONCLUSIONS: A ceiling mounted lead glass shield is an effective radiation protection for the head, but in clinical practice, optimal positioning of a ceiling mounted lead shield may not always be possible, particularly during complex cases when radiation protection may be most relevant. Added protection using these novel guards may compliment the shielding effect of the ceiling mounted lead shield. The head protector stand-alone did not provide sufficient protection of the head. The extended thyroid protector stand-alone provided sufficient protection in the lower and middle sections of the head and neck.

[Improved Protective Equipment for NICU Portable Radiography].

We have been developing protective equipment for portable radiography in neonatal intensive care units because the portable radiography's X-ray tube is in close proximity to the head of the nurse who is assisting the patient. Although our initial protective-equipment design was highly effective, there were some concerns that it obstructed the view of the patient and was difficult to handle. To overcome this problem, we have developed two new types of protective device: a narrow-type 0.13 mmPb device, 17 cm long and 45 cm wide (weight 200 g); and a wide type with a wider core material, 45 cm long and 25 cm wide (weight 300 g), both of which can be hung from the collimator cover of mobile X-ray equipment. The measured protective effectiveness was 80.6% at head height for the wide type and 76.8% for the narrow type. A survey of nurses regarding the new protective devices revealed no significant differences between the two types in terms of visibility and whether the devices would be an obstacle when assisting patients. The nurses preferred the wider type, which offered better protection. Radiological technologists also liked that both types were easy to handle because the irradiation field could be adjusted even after the device was fitted. Both types of the new protective device are thus expected to be useful in clinical practice in terms of their high protective effect and improved ease of handling.

Scatter radiation levels in X-ray rooms during chest radiography.

This research focused on the determination of scatter radiation levels in x-ray rooms during chest radiography. 108 patients were examined. Four x-ray machines (A, B, C, and D) were used during the research from three centers. Three positions were considered in this study; position Q just beside the (Bucky stand), position R, which is 150 cm from the left of the Bucky stand towards the door and position T, 200 cm from the Bucky stand to the radiographer's protective screen respectively. Two machines (A and B) from center 1 and one machine from center 2 (C) and one machine from center 3 (D). The body mass index (BMI) of the participants ranged from 20 to 25 kgm-2 with mean value of 23.97 kgm-2. The background radiation level was read using Radalert 100 m before any exposure, and the mean background level was 0.298 mR/h. The mean of the scatter radiation doses obtained from positions Q with respect to the four machines A, B, C, and D, were 0.109, 0.201, 0.204, 0.200 mR/h (9.166, 16.903, 17.156, 16.819 mSv/yr) and their standard deviations were ±0.052, ±0.053, ±0.064, and ±0.081 respectively. The results were comparable with previous studies. The study recommends staff education and training in determination of radiation levels for enhanced work safety.

Technical note: Characteristics of the energy spread kernels of scattered radiation in an x-ray room.

PURPOSE: To describe the scattered radiation spectra inside an x-ray room for different scattering conditions. METHODS: Monte Carlo simulations of an x-ray room using phantoms of different size, varying field sizes, and a range of mono-energetic beams were carried out. For each energy, the particle fluence spectrum of scattered photons was collected at different spherical zones to describe the radiation reaching the different boundaries of the x-ray room. The effect on the scattered spectrum of the room floor was also considered. RESULTS: The scattered spectra for mono-energetic primary beams at a given spherical zone give rise to oriented energy spread kernels (OESKs) that can be used to calculate the scattered spectrum for any poly-energetic beam at that zone. Despite the large differences, which can be seen in the OESKs when the scattering conditions vary, an important invariance is also observed: the position of the broad scatter peak for a given primary energy and zone. CONCLUSIONS: The result of breaking down the calculation of the scattered radiation spectrum into the different factors that influence it allows estimating the spectrum in a wide range of situations. The invariant position of the broad scatter peak can be used to estimate the highest energy of the scattered photons for a given primary energy and zone, which may determine radiation shielding needs.

Assessment of Scattered Dose to the Eye in Dentistry: A Systematic Review.

Cone-beam computed tomography (CBCT) is a tool for dental imaging of impactions, maxillofacial discrepancies, facial trauma, and tumors. In addition, It is used in treatment planning for dental implants, orthognathic surgery, and general maxillofacial surgery. There are no standardized methods for utilizing CBCT dosimetry, and there is no consensus among dental and medical physics health professionals regarding dental CBCT imaging procedures. The eyes and thyroid glands are radiosensitive organs that lie outside the primary beam but receive a significant amount of radiation due to scattered radiation. This study aimed to assess the dose to eye lens in patients imaged using CBCT. This review aims to evaluate the scattered doses to the eye from CBCT among adult patients seeking dental treatment. The search included published articles in the Web of Science, PubMed (MeSH and Web PubMed), Medline, and Google Scholar databases using the appropriate keywords from January 2010 to July 2022. The inclusion criteria were based on the method of dose measurement (phantom studies using Optically stimulated luminescence (OSL) and Thermoluminescent dosimeter (TLD), language, and type of protocol used. A literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and flow chart. Out of 653 articles identified, 5 met the inclusion criteria. The results show that the scattered radiation dose ranged between 0.103 mSv and 8.3 mSv. This variation exists due to the difference in the field of vision (FOV), phantom exposure, dosimeters used, degree of rotation in the protocol, and finally, the scanner used. The scattered dose to the eye from CBCT is higher than the background radiation, with huge variability in the range of the dose measured. Clear guidelines for utilizing CBCT should be implemented, and dose reference levels should be established for benchmarking and optimization in practice.

[Efficacy of L-shaped Shielding in Interventional Radiology by Transradial Approach and Consideration of Methods for Appropriate Use].

The present study investigated how effective an L-shaped shield was, depending on its position, in reducing a doctor's exposure to radiation during catheterization to access the transradial approach (TRA). The shield's effectiveness was evaluated by measuring the air kerma where the doctor stood under four conditions: with and without the shield, and with and without the shield in conjunction with conventional protection. To enable the shield to be positioned correctly in clinical practice, an illustrated instruction decal affixable to the shield's doctor-facing surface was produced, and the effectiveness of the decal was verified by means of a crossover test in which, as subjects of the study, different nurses set up the shield with and without the decal affixed to it. In the test, in which a human body phantom was used, the C-arm set at the PA angle, and the shield positioned 10 cm from the axilla of the phantom, the shield's effectiveness at 100 cm, 130 cm, and 160 cm above the floor where the doctor stood was 55%, 77%, and 47%, respectively. The effectiveness increased when the shield was positioned closer to the axilla. A significant difference in the positioning of the shield by the subjects was observed depending on whether or not the decal was affixed ( p<0.05, Wilcoxon signed-rank test), indicating that the use of the decal improved the positioning. It was concluded that, positioned correctly, the shield could effectively reduce the doctor's exposure to radiation during TRA.

Determination of scattered radiation dose for radiological staff during portable chest examinations of COVID-19 patients.

The COVID-19 pandemic has resulted in a large increase in the number of patients admitted to hospitals. Radiological technologists (RTs) are often required to perform portable chest X-ray radiography on these patients. Normally, when performing a portable X-ray, radiation protection equipment is critical as it reduces the scatter radiation dose to hospital workers. However, during the pandemic, the use of a lead shield caused a heavy weight burden on workers who were responsible for a large number of patients. This study aimed to investigate scatter radiation doses received at various distances, directions, and positions. Radiation measurements were performed using the PBU-60 whole body phantom to determine scatter radiation doses at 100-200 cm and eight different angles around the phantom. The tests were conducted with and without lead shielding. Additionally, the doses were compared using the paired t test (p < 0.005) to determine suitable positions for workers who did not wear lead protection that adhered to radiation safety requirements. Scatter radiation doses of all 40 tests showed a highest and lowest value of 1285.5 nGy at 100 cm in the anteroposterior (AP) semi upright position and 134.7 nGy at 200 cm in the prone position, respectively. Correlation analysis between the dosimeter measurement and calculated inverse square law showed good correlation, with an R2 value of 0.99. Without lead shielding, RTs must stay at a distance greater than 200 cm from patients for both vertical and horizontal beams to minimize scatter exposure. This would allow for an alternative way of performing portable chest radiography for COVID-19 patients without requiring lead shielding.

Effectiveness of radiation protection systems in the cardiac catheterization laboratory: a comparative study.

BACKGROUND: As numbers and complexity of percutaneous coronary interventions are constantly increasing, optimal radiation protection is required to ensure operator safety. Suspended radiation protection systems (SRPS) and protective scatter-radiation absorbing drapes (PAD) are novel methods to mitigate fluoroscopic scattered radiation exposure. The aim of the study was to investigate the effectiveness regarding radiation protection of a SRPS and a PAD in comparison with conventional protection. METHODS: A total of 229 cardiac catheterization procedures with SRPS (N = 73), PAD (N = 82) and standard radiation protection (N = 74) were prospectively included. Real-time dosimeter data were collected from the first operator and the assistant. Endpoints were the cumulative operator exposure relative to the dose area product [standardized operator exposure (SOE)] for the first operator and the assistant. RESULTS: For the first operator, the SRPS and the PAD significantly decreased the overall SOE compared to conventional shielding by 93.9% and 66.4%, respectively (P < 0.001). The protective effect of the SRPS was significantly higher compared to the PAD (P < 0.001). For the assistant, the SRPS and the PAD provided a not statistically significant reduction compared to conventional shielding in the overall SOE by 38.0% and 30.6%, respectively. CONCLUSIONS: The SRPS and the PAD enhance radiation protection significantly compared to conventional protection. In most clinical scenarios, the protective effect of SRPS is significantly higher than the additional protection provided by the PAD. Comparison of the additional radiation protection provided by protective scatter-radiation absorbing drapes (PAD) and the suspended radiation protection system (SRPS) system over standard protection with lead aprons.

[Creation of Protective Equipment for Portable Radiography in Neonatal Intensive Care Unit].

Portable imaging in the NICU requires the assistance of a nurse, and the nurse is in close proximity to the X-ray tube, In all, 64 percent of our nurses thought that additional protective equipment was needed. Therefore, a radiation protection device was created and its usefulness was verified. A protective equipment of 0.13 mmPb with a width of 38 cm and a length of 70 cm was made and hung from the mono-tank X-ray unit of the mobile X-ray unit. The position of the nurse was set at 30 cm outward from the center of the irradiation field, and the protective effect was measured at three points: (a) the patient's height, (b) 30 cm above the patient, and (c) 60 cm above the patient. For the imaging conditions, a 2-liter plastic bottle filled with water was placed in the incubator, and measurements were taken with an SID of 100 cm, irradiated field of 20.3 cm×25.4 cm, tube voltage of 58 kV, and tube current-time product of 10 mAs, which was converted to the actual imaging condition of 1 mAs. Based on the results obtained, a questionnaire survey was conducted on nurses' thoughts for the protective equipment created for them. Only 3% reduction in height of (a) where no protective equipment is reached but (b) 50% and (c) 92%, respectively. In all, 82 percent of the nurses had a favorable impression of the new protective equipment. It is expected that the protective equipment designed to control lens dose and reduce anxiety of nurses will be useful.