Dosimeters Research Articles

A follow‐up questionnaire survey 2022 on radiation protection among 464 medical staff from 34 endoscopy–fluoroscopy departments in Japan

We surveyed and reported low protective equipment usage and insufficient knowledge among endoscopy-fluoroscopy departments in Japan in 2020. Two years later, we conducted a follow-up survey of doctors, nurses, and technologists in Japan. We conducted a questionnaire survey on radiation protection from May to June 2022. The participants were medical staff, including doctors, nurses, and radiological and endoscopy technicians in endoscopy-fluoroscopy departments. The questionnaire included 17 multiple-choice questions divided into three parts: background, equipment, and knowledge. We surveyed 464 subjects from 34 institutions. There were 267 doctors (58%), 153 nurses (33%), and 44 technologists (9%). The rate of wearing a lead apron was 98% in this study. The rates of wearing a thyroid collar, lead glasses, and radiation dosimeter were 27%, 35%, and 74%, respectively. The trend of the protective equipment rate was similar to that of our previous study; however, radiation dosimetry among doctors was still low at 58%. The percentage of subjects who knew the radiation exposure (REX) dose of each procedure was low at 18%. Seventy-six percent of the subjects attended lectures on radiation protection, and 73% knew about the three principles of radiation protection; however, the concept of diagnostic reference levels was not well known (18%). Approximately 60% of the subjects knew about the exposure dose increasing cancer mortality (63%) and the 5-year lens REX limit (56%). There was some improvement in radiation protection equipment or education, but relatively little compared to the 2020 survey of endoscopy departments.

THE DEVELOPMENT OF GAMMA RADIATION DOSIMETERS REAL-TIME NETWORK-BASED SENSOR WIRELESS IEEE 802.15.4 PROTOCOL

Several studies have been carried out on the development of real-time gamma radiation dosimeter based on the wireless sensor network (WSN) protocol IEEE 802.15.4. WSN technology can be adopted to develop a gamma radiation dose monitoring system on a large scale due to its real-time, centralized, efficient, and relatively low-cost attributes. This study aims to develop a personal radiation dosimeter that can collect data from the measurement results of several sensor nodes or multi-sensors. The measurement results of radiation dose values from many radiation workers are sent to a coordinator node consisting of the Xbee module and Arduino as a microcontroller. The system test is compared with a calibrated dosimeter reading and is expected to be one of the instruments for determining radiation dose in real-time. It can also reduce the risk of receiving a radiation dose that exceeds the threshold allowed by the ionizing control agency and a program in radiation protection. Changes in the intensity of radiation emitted by Cs-137 (gamma radiation) are carried out by varying each detector's distance to the source, which indirectly varies the value of the dose rate received by the detector. This relationship is shown from the value of R2 = 0.99, which indicates a strong correlation between changes in the dose given to the detector's response being developed. The system built is efficient, inexpensive, and collecting radiation exposure data can monitor radiation exposure received by workers in real-time. This technique can help speed up reporting of radiation exposure received by radiation workers.

Proposed Institutional Diagnostic Reference Levels in Computed and Direct Digital Radiography Examinations in Two Teaching Hospitals

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana.Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (μGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75<sup>th</sup> percentiles values of the estimated ESDs for nine radiographic projections.Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively.Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

Enhanced X-ray Dose Response of Radio-fluorescent Hydrogels Enabled by Persulfate Salts.

Coumarin 3-carboxylic acid (CCA)-loaded radio-fluorescent hydrogels have attracted interest for ionizing radiation dosimeters, but their sensitivity needs to be improved. In this study, we added ammonium persulfate (APS) to a polyacrylamide (PAAm)-CCA hydrogel. The introduction of APS improved the hydrogel dose sensitivity to 336.02Gy- 1, which is 1.8 times that of the counterpart without APS. Our hydrogel can measure the X-ray dose in a range of 0 - 15Gy with a lower limit of detection (LOD) of 0.1Gy. Additionally, the hydrogel can sense X-ray doses within a wide range of the dose rate and temperature, and the dose‒response can be well retained 7 days postirradiation. Therefore, we think this study provides a simple and robust method to improve the sensitivity of CCA hydrogel dosimeters, presenting great potential in clinical radiotherapy.

Comparative study of two mixture dyes based on PVA for industrial use as gamma radiation dosimeter

New film dosimeters PVA/(DCP/CR) and PVA/(DCP/BPR) have been prepared through the casting method. The colorimetric properties of both films changed from violet to pink and from green to yellow with exposures to gamma rays between 0–80 and 0–40 kGy, respectively. The color response was accelerated with chloral hydrate to half of the radiation dose between 0–40 and 0–20 kGy for both systems, respectively. The UV–visible spectrophotometer shows outstanding stability of the prepared dosimetric systems. Relative humidity was studied and the response indicated that both films possess very good stability during irradiation.Graphical abstract

Thermoluminescent characterization and defect studies of graphite-rich media under high dose neutron exposure

Thermoluminescence (TL) materials have a broad variety of uses in various fields, such as clinical research, individual dosimetry, and environmental dosimetry, amongst others. However, the use of individual neutron dosimetry has been developing more aggressively lately. In this regard, present study establishes a relationship between the neutron dosage and the optical property changes of graphite-rich materials caused by high doses of neutron radiation. This has been done with the intention of developing a novel, graphite-based radiation dosimeter. Herein, the TL yield of commercially graphite-rich materials (i.e. graphite sheet, 2B and HB grade pencils) irradiated by neutron radiation with doses ranging from 250 Gy to 1500 Gy has been investigated. The samples were bombarded with thermal neutrons as well as a negligible amount of gamma rays, from the nuclear reactor TRIGA-II installed at the Bangladesh Atomic Energy Commission. The shape of the glow curves was observed to be independent of the given dosage, with the predominant TL dosimetric peak maintained within the region of 163 °C–168 °C for each sample. By studying the glow curves of the irradiated samples, some of the most well theoretical models and techniques were used to compute the kinetic parameters such as the order of kinetics (b), activation energy (E) or trap depth, frequency factor (s) or escape probability, and trap lifetime (τ). All of the samples were found to have a good linear response over the whole dosage range, with 2B grade of polymer pencil lead graphite (PPLGs) demonstrating a higher level of sensitivity than both HB grade and graphite sheet (GS) samples. Additionally, the level of sensitivity shown by each of them is highest at the lowest dosage that was given, and it decreases as the dose increases. Importantly, the phenomenon of dose-dependent structural modifications and internal annealing of defects has been observed by assessing the area of deconvoluted micro-Raman spectra of graphite-rich materials in high-frequency areas. This trend is consistent with the cyclical pattern reported in the intensity ratio of defect and graphite modes in previously investigated carbon-rich media. Such recurrent occurrences suggest the idea of employing Raman microspectroscopy as a radiation damage study tool for carbonaceous materials. The excellent responses of the key TL properties of the 2B grade pencil demonstrate its usefulness as a passive radiation dosimeter. As a consequence, the findings suggest that graphite-rich materials have the potential to be useful as a low-cost passive radiation dosimeter, with applications in radiotherapy and manufacturing.

Radiation dosimeter and charge detector onboard BeiDou navigation satellites in MEO

Abstract The orbit of BeiDou satellite system is a very ideal space environment monitoring area. The radiation dosimeters are present on this series of navigation satellites, and they are respectively installed in the x, y and z positions. A charge detector installed in the satellite cabin is used for monitoring satellite deep charging potential. Radiation dosimeters select the 100 nm P-channel metal oxide semiconductor (PMOS) sensors, whose monitoring range can reach 2 × 106 rad (Si). In the circuit design part, the “zero temperature coefficient” current of the PMOS is used as the constant current source for measuring, which effectively reduces the influence of temperature effect. Three radiation dosimeters realize the daily dose change monitoring during the satellite’s operation, and the detection accuracy is high. The deep charging potential sensor adopts the equivalent capacitor design which is composed of the outer optical quartz glass and the inner circular gold-plate. The two kinds of detection instruments have the characteristics of small volume, low power consumption and high detection accuracy. The detection results show that they have important application value for space environment prediction and guarantee.

Gallosilicate glass and fiber for radiation detection

AbstractAs ionizing radiation can cause harmful effects to human and electronic devices, accurate dose monitoring plays an important role in fields such as radiotherapy, nuclear industry, and aerospace. Currently, it is still a challenge to fabricate a miniaturized dosimeter that can achieve real‐time monitoring. Here, a gallosilicate glass with potential application in visualization detection of ultraviolet and ionizing radiation, as well as cumulative dose measurement, is presented. Color centers are induced in the glass upon exposure to ultraviolet or ionizing radiation, resulting in a darkening effect. The color change of glass is related to the energy and intensity of incident photons and can be erased by subsequent heat treatment. Electron paramagnetic resonance measurement indicates that the formation of color centers is associated with non‐bridging oxygen hole centers related to gallium. The glass can be fabricated into fiber with perfect core‐cladding structure, which provides an alternative for preparing a new type of high‐sensitivity radiation dosimeter.

Luminescence properties of Ce-doped ZrO2 phosphors synthesized by combustion method.

Zr1-x Cex O2 with x = 0.005, 0.01, 0.02, and 0.03 samples were synthesized using a combustion technique. The X-ray diffraction results revealed that Ce-doped ZrO2 nanoparticles were in a monoclinic structure up to 1mol% Ce concentration. The increase in the Ce concentration caused more distortion in the monoclinic structure of zirconia. The samples showed a mixed phase (monoclinic + tetragonal) beyond 1mol% Ce content. The crystallite size (D) and strain (ε) were calculated from the Williamson-Hall equation. The D decreased from 25 ± 1 to 20 ± 1nm and ε increased from 0.03 to 0.28% with an increase in Ce concentration. Photoluminescence (PL) spectra of Zr1-x Cex O2 showed emission in the blue region under an excitation wavelength of 290 nm. Zr0.995 Ce0.005 O2 showed the highest PL intensity with an average lifetime of 0.93 μs, and the PL intensity decreased with the increase in the Ce concentration. Thermoluminescence (TL) glow curves of Zr1-x Cex O2 were measured after gamma irradiation (500 Gy) with a heating rate of 5K s-1 . The TL curve of Zr0.995 Ce0.005 O2 showed two prominent peaks at 412 K (peak 1) and 600 K (peak 2). The first TL glow peak was shifted towards a higher temperature at 440 K above 1mol% Ce concentration. Repetitive TL measurements on the same aliquot exhibited excellent repeatability. Kinetic parameters associated with the TL peaks were calculated using the curve fitting method. Peak 1 followed non-first-order kinetics. The value of the activation energy of the 440 K peak was found to be 0.95 ± 0.01 eV for Zr0.99 Ce0.01 O2 . These findings showed that Zr1-x Cex O2 might be used in lighting and radiation dosimeter applications.

First Combined, Double‐Density LCV‐Pluronic F‐127 Radiochromic Dosimeter Mimicking Lungs and Muscles

AbstractThis work reports on a new type of combined radiochromic ionizing radiation dosimeter for radiotherapy. The LCV‐Pluronic F‐127 serves for this purpose, which is a leuco crystal violet embedded in a physical hydrogel matrix of poly(ethylene oxide)‐block‐poly(propylene oxide)‐block‐poly(ethylene oxide) (Pluronic F‐127) with additives. This dosimeter responds to ionizing radiation by developing a blue color with an intensity related to the radiation dose. The LCV‐Pluronic F‐127 dosimeter is improved for lower temperature stability by adding sodium chloride (NaCl). Subsequently, a method for manufacturing the LCV‐Pluronic F‐127 lung mimicking dosimeter is proposed. Next, the LCV‐Pluronic F‐127 3D composite dosimeter is elaborated, which contains in one container two dosimetric zones of different densities mimicking soft tissues: muscles and lungs. The following are investigated: i) LCV‐Pluronic F‐127 phase transition with and without NaCl, ii) dose response characteristics, iii) stability during storage, iv) foams characteristics – lung mimicking dosimeter, v) tissue equivalence, and vi) dose response of LCV‐Pluronic F‐127 combined dosimeter to a medical accelerator X‐ray irradiation. In summary, this work proves the possibility of formation complex dosimeters and opens a new area of research toward the development and application of such dosimeters containing dosimetric zones corresponding to many tissues in one vial.

Optically Stimulated Luminescence in LiF–MgF2 system and its response as medical radiation dosimeter

Optically Stimulated Luminescence (OSL) based dosimeters are garnering attention in the field of radiation dosimetry due to a number of benefits like portable equipment, easy and efficient excitation and read out process, re-readability of the dose etc.. Though varieties of fluoroperovskites have been studied as OSL materials, no research on LiMgF3 (Lithium Magnesium Fluoride) as an OSL material has yet been conducted. In the current work, LiF–MgF2 system with a low effective atomic number was synthesized using the high temperature solid state reaction approach and its OSL dosimetry properties were investigated. The prepared sample was thoroughly characterized by employing a variety of techniques, such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and UV–Vis (ultraviolet–visible) spectrophotometry. The structure of the sample was found to be polycrystalline with size in the micrometre range. OSL properties of LMF have been investigated for different doses of gamma and beta along with related OSL kinetic parameters. It exhibits good dose linearity under blue stimulation for gamma (100 mGy - 700 Gy) and beta (30 mGy - 5Gy) radiation. We have also investigated the reusability (3%), reproducibility (2–3%), and fading (45% in 40 days) of the phosphor. To check the viability of the sample in radiation dosimetry under medical treatment in radiotherapy, various dosimetric properties were studied in Linear Accelerator (LINAC) x-rays in MV energy range and Cobalt-60 gamma radiation. These studies include the response of the phosphor to various energies (called energy dependence), field size effect, the effect of the dose rate of the radiation beam, and relative depth dose response. The overall response of the phosphor (comparable with ion chamber in RT experiments) makes the material a potential candidate to be used as an OSL phosphor in medical radiation dosimetry.

Effect of radiation exposure on function human body by CBC parameter for workers in nuclear medicine field

In this study, eight cases of workers in gamma camera scans and Positron Emission Tomography (PET/CT scan) fields (employed for various medical diagnoses) had their complete blood counts (CBCs) assessed. From the first hour of work until the last, the investigation of radiation’s impact on hematology was ongoing. By using a personal dose meter (Geiger Badge), the radiation exposure reading for a whole workday is directly recorded in (μSv). The study concluded that while the number of WBC count increased for all workers after radiation exposure, the number of RBC count decreased after exposure, suggesting that RBC amount may be a reliable indicator of exposure degree.

RECENT ADVANCES IN COMPUTED TOMOGRAPHY RADIATION DOSIMETRY

Computer tomography (CT) has proved fundamental in image evaluation throughout the past three decades. By combining rapid scanning with high-quality data sets, multi-detector technology continues to influence practice patterns. This has led to new applications and improved use in conventional applications. However, the increased use of CT has generated significant concern regarding the high radiation doses received by patients during CT scans compared to traditional radiography examinations. Many studies have been undertaken on minimizing patient dose and adhering to the as low as reasonably achievable (ALARA) principle. A total of 40 English articles from PubMed, Science Direct and Google Scholar were systematically summarized in this review paper to introduce the growth of CT scan from single-slice to multi-slice technology from 2000 until December 2020 as well as dual-energy and multi-detector CT technologies. The important role of utilizing CT radiation dosimeters for CT dose measurement is defined included CT dose reduction techniques.

Flexible real-time skin dosimeter based on a thin-film copper indium gallium selenide solar cell for electron radiation therapy.

Various dosimeters have been proposed for skin dosimetry in electron radiotherapy. However, one main drawback of these skin dosimeters is their lack of flexibility, which could make accurate dose measurements challenging due to air gaps between a curved patient surface and dosimeter. Therefore, the purpose of this study is to suggest a novel flexible skin dosimeter based on a thin-film copper indium gallium selenide (CIGS) solar cell, and to evaluate its dosimetric characteristics. The CIGS solar cell dosimeter consisted of (a) a customized thin-film CIGS solar cell and (b) a data acquisition (DAQ) system. The CIGS solar cell with a thickness of 0.33mm was customized to a size of 10×10mm2 . This customized solar cell plays a role in converting therapeutic electron radiation into electrical signals. The DAQ system was composed of a voltage amplifier with a gain of 1000, a voltage input module, a DAQ chassis, and an in-house software. This system converted the electrical analog signals (from solar cell) to digital signals with a sampling rate of ≤50kHz and then quantified/visualized the digital signals in real time. We quantified the linearity/ sampling rate effect/dose rate dependence/energy dependence/field size output factor/reproducibility/curvature/bending recoverability/angular dependence of the CIGS solar cell dosimeter in therapeutic electron beams. To evaluate clinical feasibility, we measured the skin point doses by attaching the CIGS solar cell to an anthropomorphic phantom surface (for forehead, mouth, and thorax). The CIGS-measured doses were compared with calculated doses (by treatment planning system) and measured doses (by optically stimulated luminescent dosimeter). The normalized signals of the solar cell dosimeter increased linearly as the delivered dose increased. The gradient of the linearly fitted line was 1.00 with an R-square of 0.9999. The sampling rates (2, 10, and 50kHz) of the solar cell dosimeter showed good performance even at low doses(<50 cGy). The solar cell dosimeter exhibited dose rate independence within 1% and energy independence within 3% error margins. The signals of the solar cell dosimeter were similar(<1%) when penetrating the same side of the CIGS cell regardless of the rotation angle of the solar cell. The field size output factor measured by the solar cell dosimeter was comparable to that measured by the ion chamber. The solar cell signals were similar between the baseline (week 1) and the last time point (week 4). Our detector showed curvature independence within 1.8% (curvatures of<0.10mm- ) and bending recovery (curvature of 0.10mm-1 ). The differences between measured doses (CIGS solar cell dosimeter vs. optically stimulated luminescent dosimeter) were 7.1%, 9.6%, and 1.0% for forehead, mouth, and thorax, respectively. We present the construction of a flexible skin dosimeter based on a CIGS solar cell. Our findings demonstrate that the CIGS solar cell has a potential to be a novel flexible skin dosimeter for electron radiotherapy. Moreover, this dosimeter is manufactured with low cost and can be easily customized to various size/shape, which represents advantages over other dosimeters.

Microfluidics unveil nucleation and growth in the radiolytic synthesis of colloidal silver and allow X-ray detection with nanoclusters

We developed a two-stage microfluidic reactor consisting of one hot and one cold region to systematically investigate a radiolytic method to synthesize colloidal silver and to improve the sensitivity of radiation dosimeters based on the Ag nanoparticles plasmon intensity. The microfluidic approach avoided growth during the heating stage, resulting in the total absence of a plasmon band for non-irradiated samples, greater control of the particle size distribution, and decreased minimal detectable dose. Doses as low as 0.2 Gy could be detected with sensitivities higher than the reported in the literature. This is a great achievement once most chemical dosimeters, besides 3D gels, are not sensitive to such low doses. Samples prepared in the microreactor and exposed to doses from 0 to 0.75 Gy presented an unexpected absorption band above 500 nm and a fluorescence emission around 380 nm, evidencing the presence of Ag nanoclusters (AgNCs). Both, absorption and emission bands from AgNCs, increase in the 0-0.75 Gy range, suggesting that nucleation predominates in the microreaction stage and in the radiolytic step for doses below 1 Gy. Decreased fluorescence intensity and undetected absorption above 500 nm indicate that growth prevails for doses ≥1 Gy. Thus, our work presents a novel way to measure doses based on silver nanoclusters, including both absorption and emission as dosimetric parameters. Besides unveiling nucleation and growth mechanisms associated to nano clusters and particles formation in this radiolytic microreaction, the results put the spotlight on new possibilities for enhanced radiation detection employing AgNCs.

Development of a BODIPY-based ratiometric fluorescence off-on dosimeter for gamma radiation

A ratiometric fluorescence “off-on” dosimeter is developed using bare BODIPY dye, 8-(N,N-dimethylanilino) BODIPY. The dosimeter is useful for the detection of gamma radiation in the range of 0.5–150 Gy with a 0.5 Gy limit of detection.

A Power/Hardware-Efficient SiPM Readout IC Embedded in a Boost Converter for Mobile Radiation Dosimeters

A radiation detection system provides radiation intensity to protect human life from hazardous radiation. However, the prior portable radiation detection system (mobile radiation dosimeter) structures had a problem in that various subsystems had to be designed with complex circuits. First, since the radiation detector must be driven by a relatively high voltage, a high-efficient boost converter that can receive the battery voltage and generate a high bias voltage must be implemented. Second, sophisticated sensor interface circuits that can convert the analog signal generated by the radiation detector to digital value must also be implemented. To reduce the complexity of the mobile radiation dosimeters, a power- and hardware-efficient radiation detection system IC is presented for mobile radiation dosimeters. The current value of a silicon photomultiplier (SiPM) used as a radiation detector is sensed from the control information of a boost converter in the process of regulating a voltage to bias the SiPM. Due to this embedded sensing function, no additional hardware and power consumption are required for implementing and operating separate sensor interface circuits while providing sufficient radiation sensing performance. The implemented radiation detection system IC achieves 0.217- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> input referred noise performance over 1-kHz signal bandwidth and 10-mA maximum allowable linear input current range. In addition, the proposed dc–dc boost converter can generate a high enough voltage (∼27 V) to drive SiPM from a lithium-ion battery with an efficiency of 72%. The irradiation test with radiation check source ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs) demonstrates that the bias voltage is well regulated in the presence of high-energy radiation particles.

Design and Development of a Low-cost Integrated Dosimeter for External Beam Dosimetry in Radiation Oncology.

Radiation dosimeters play a crucial role in radiation oncology by accurately measuring radiation dose, ensuring precise and safe radiation therapy. This study presents the design and development of a low-cost printed circuit board (PCB) dosimeter and an integrated electrometer with sensitivity optimized for dose rates intended for use in megavoltage radiation therapy. The PCB dosimeter was designed in KiCad, and it uses a low-cost S5MC-13F general-purpose 1 kV 5A power diode as a radiation detector. The dosimeter is calibrated against a known dose derived from an ionization chamber and tested for dose linearity, dose rate dependence, field size dependence, and detector orientation dependence. The observed average dose differences between the delivered and measured doses for most measurements were found to be < 1.1%; the dose rate linearity between 100 MU/min and 1400 MU/min was found to be within 1.3%. This low-cost architecture could successfully be adapted further for a scalable, cost-effective dosimetry solution through firmware or circuit design.

The HP(3,α) dose response of direct reading survey meters

Direct reading survey meters, designed for the measurement of shallow dose rates, are commercially available. Examples of such instruments include the Fluke 451B, the BOT P200 m with SM20 probe, the Eberline RO-2A and the RAM-Ion. We investigated the potential use of these instruments, as eye lens dose rate meters, with the addition of low-Z filters of suitable thicknesses. Their responses to 90Sr/90Y beta particles and to photons of varied qualities, as functions of angles of incidence, were measured. It was determined that most instruments can be suitably modified to operate as useful eye-lens dose rate meters. Their use in the field could assist radiation protection professionals in the assessment of radiological risk to the lens of the eye. This will allow recommendations on appropriate PPE and dosimetry in individual workplace settings.

Assessment of Radiation Exposure Dose for Nuclear Medicine Workers from 18F-FDG, 99mTc MDP, and 99mTc.

Nuclear medicine or diagnostic radiology personnel are always exposed to low-level radiation from radionuclides used in medical diagnostics, which lead to potential biological hazards or effects. External exposure for workers in two nuclear medicine centers was measured by recruiting 120 patients. Three nuclear medicine examinations were performed using F18-FDG PET/CT,99mTc- MDP bones scan, and 99mTc thyroid scan by a digital radiation dosimeter. The average received accumulative radiation dose for workers was found to be 0.838±0.17, 0.527±0.11, and 0.270±0.05 µSv for F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. The annual effective dose for workers was estimated to be 2.09±0.42, 1.34±0.27, and 0.68±0.14 mSv, respectively. Moreover, the average patient-to-staff dose coefficients were found to be 0.024±0.005, 0.003±0.001, and 0.007±0.002 µSv m2/MBq h for F18- FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. It is clear from the results that the radiation doses received by workers during the nuclear medicine imaging examinations were less than the doses recommended by the International Commission on Radiological Protection (ICRP) for such examinations.