Glass Dosimeter Research Articles

Measurement of Radiation Dose of HR CT and Low Dose CT by using Anthropomorphic Chest Phantom and Glass Dosimetry

The purpose of this study is to provide basic clinical data by evaluating images, measuring absorbed dose and effective dose by using high resolution CT and low dose CT by using anthropomorphic chest phantom and glass dosimeter. Tissue dose was measured by inserting a glass dosimeter into the anthropomorphic chest phantom. A 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany) and CARE Dose 4D were used, and the parameters of the high resolution CT were 120 kVp, Eff. Scan parameters of mAs 104, scan time 7.93 s, slice 1.0 mm (Acq. 64 × 0.6 mm), convolution kernel (B60f sharp) were used, and low dose CT was 120 kVp, Eff. mAs 15, scan time 7.41 s, slice 3.0 mm (Acq. 64 × 0.6 mm), scan of convolution kernel B50f medium sharp. CTDIvol was measured at 8.01 mGy for high resolution CT and 1.18 mGy for low dose CT. Low dose CT scans showed 85.49% less absorbed dose than high resolution CT scans.

Establishment of Diagnostic Reference Levels for Radiography in 10-year-old Pediatric Patients in Republic of Korea

The diagnostic reference levels (DRLs) for a 10-year-old patient were established for the most common types of general radiography in this study, using a glass dosimeter and a phantom corresponding to the international standards. The DRLs are set by measuring the entrance surface doses (ESD) at 211 medical institutions. The ESD of the skull posterior-anterior (PA) projection is between 0.11 and 5.59 mGy, with the average dose at 1.03 mGy, and the third quartile value at 1.17 mGy. The ESD of the skull lateral (LAT) projection is between 0.08 and 5.20 mGy, with the average dose at 0.78 mGy, and the third quartile value at 0.96 mGy. The ESD of the chest PA projection is between 0.01 and 1.38 mGy, with the average dose at 0.18 mGy, and the third quartile value at 0.20 mGy. The ESD of the chest LAT projection is between 0.04 and 3.36 mGy, with the average dose at 0.42 mGy, and the third quartile value at 0.46 mGy. The ESD of the abdomen AP projection is between 0.09 and 4.64 mGy, with the average dose at 0.85 mGy, and the third quartile value at 1.13 mGy. The ESD of the pelvis AP projection is between 0.1 and 5.26 mGy, with the average dose at 0.85 mGy, and the third quartile value at 1.06 mGy. Based on third quartile values and through clinical expert consultation, the DRLs for 10-year-olds in Korea were established at 1.1 mGy for skull PA, 0.9 mGy for skull LAT, 0.2 mGy for chest PA, 0.4 mGy for chest LAT, 1.1 mGy for abdomen AP, and 1.0 mGy for pelvis AP.

DEVELOPMENT OF A JAPANESE INFANT HEAD-CHEST PHANTOM AND INVESTIGATION OF THE CURRENT STATUS OF INFANT HEAD CT EXAMINATIONS IN JAPAN.

The aim of this study was to develop a head-chest phantom that could mimic the physique of a Japanese 0.5-year-old child and to investigate the current status of exposure dose in infant head computed tomography examinations in Japan. The phantom was produced by machine processing, and radiophotoluminescence glass dosemeters were installed in the phantom for dose measurement. Organ doses were measured for seven different head scan protocols routinely used in three hospitals. In this study, the average dose of the brain and lens within the scan region was equivalent to that measured using infant phantoms in previous studies. In contrast, the doses of both salivary glands and thyroid glands adjacent to the scan region were 1.4-1.8 times higher than those in previous studies. Expansion of the scan area accompanied by a transition of the scan mode from non-helical to helical may have resulted in the differences in organ doses.

Radiation Protective Effect of the Thyroid Gland Using Bolus Protector in the Dental Cone Beam Computed Tomography

In order to minimize the radiation exposure dose of the thyroid site at dental cone-beam computer tomography, a protector using a Bolus was prepared, and the radiation shielding effect and the appropriateness of the image were evaluated. Using a dental cone-beam computed tomography (CBCT), a glass dosimeter was attached to the left and right sides of the thyroid for a dental radiation phantom, and the radiation dose was measured. The absorbed dose for each shield was measured by another method to 10 mm, 20 mm, and 30 mm-thickness, respectively. Eight evaluators evaluated whether or not the medical image is appropriate. When using a 30 mm Bolus shield at the left thyroid site, the resulting value is reduced by an average of 342.67 μGy by 20.7% from the average value of 431.22 μGy measured without using a Bolus shield, the right thyroid site In the case of using 30 mm Bolus shield, it showed a dose reduction effect of 21.9% with an average of 424.56 μGy. The adequacy of the medical image was judged to be usable by both evaluators. In conclusion, the dental cone-beam computerized tomography can be used as a useful shielding material because it has a radiation shielding effect and it is possible to treat the diagnosis of the bolus protector in the thyroid without any obstruction shade in order to minimize the radiation dose.

Reduction of Operator Hand Exposure in Interventional Radiology With a Novel Finger Sack Using Tungsten-containing Rubber

The purpose of this study was to evaluate the x-ray shielding ability of a novel tungsten-particle-containing rubber-based finger sack for use in interventional radiology. Shielding rates for the air kerma (mGy m) were measured using a semiconductor dosimeter with and without the finger sack and commercial lead gloves, at a 20 cm distance from the field of view. A C-arm digital angiography system was used with x-ray tube voltages of 60, 80, 100, and 120 kVp. In addition, the 70 μm dose equivalent to the operator's finger was measured using fluorescent glass dosimeters with and without the finger sack during interventional radiology examinations. The x-ray shielding rates for 60, 80, 100, and 120 kV x rays were 98.0 ± 0.03%, 94.8 ± 0.05%, 92.3 ± 0.12%, and 90.1 ± 0.03%, respectively, with the finger sack and 69.8 ± 0.39%, 61.0 ± 0.53%, 52.3 ± 0.52%, and 47.0 ± 0.69% with the lead gloves. The x-ray shielding rates for the fluoroscopy and cine mode with the finger sack were 91.3 ± 0.21% and 56.5 ± 0.58%, respectively, while with the lead gloves they were 96.5 ± 0.04% and 67.6 ± 0.33%. The 70 μm dose equivalent for the operator's finger exposure dose was reduced by approximately 39.4% using the finger sack. The finger shields were more user friendly, had excellent radiation shielding ability against x rays, and should reduce finger exposure in interventional radiology.

In-Vivo Dosimetry for Small Animal Irradiation: A Preliminary Study

This study assessed applications for in-vivo dosimetry using a 3D printer-based, self-manufactured mouse immobilization device in a small field. The mouse immobilization device was created using a 3D printer (Makerbot Replicator, MakerBot Industries, Brooklyn, NY, USA) and consisted of the support flat, fixing units, sensor areas, and a build-up cap. Radio-photoluminescence glass dosimeters (RPLGD, GD-302M) were inserted at the upper left (UL), upper right (UR), lower left (LL), and lower right (LR) of the device at the center of the target. EBT3 film was inserted into the device at the top of the mouse’s head. Irradiation planning was performed using the ECLIPSE system after a CT simulation of mice with an immobilization device. The mice were irradiated 5 times at a dose 180 cGy with 6 MV X-rays. The dose measurements from the RPLGDs and films were compared with the doses calculated in the Eclipse system. The percentage differences between the Radiation Treatment Planning (RTP) System and RPLGD measurements were 5.56 ± 3.90%, 6.52 ± 5.32%, 10.0 ± 8.97%, and 15.9 ± 17.5% at the UL, UR, LL, and LR positions, respectively. The gamma passing rate of all film measurements exceeded 90% in the 2%/2 mm range. The error values of the 3rd measurements were outliers due to the set up. With the exception of the 3rd measurements, the percentage difference decreased to 4–7%. In this study, we evaluated the applicability of a mouse immobilization device in a small field. We performed in-vivo dosimetry using RPLGD and EBT3 film; this approach may be helpful for using radiation to accurately analyze results in animal studies.

ESTIMATION OF ORGAN DOSES AND EFFECTIVE DOSES BASED ON IN-PHANTOM DOSIMETRY FOR PAEDIATRIC DIAGNOSTIC CARDIAC CATHETERISATION.

The present study evaluated the organ doses, effective doses and conversion factors from the dose-area product to effective dose in pediatric diagnostic cardiac catheterization performed by in-phantom dosimetry and Monte Carlo simulation. The organ and effective doses in 5-y-olds during diagnostic cardiac catheterizations were evaluated using radiophotoluminescence glass dosemeters implanted into a pediatric anthropomorphic phantom and PCXMC software. The mean effective dose was 3.8 mSv (range: 1.8-7.5 mSv). The conversion factors from the dose-area product to effective dose were 0.9 and 1.6 mSv (Gy cm2)-1 for posteroanterior and lateral fluoroscopy, respectively, and 0.9 and 1.5 mSv (Gy cm2)-1 for posteroanterior and lateral cineangiography, respectively. Effective doses evaluated using the pediatric dosimetry system agreed with those obtained using PCXMC software within 12%. The dose data and conversion factors evaluated may guide the estimation of exposure doses in children undergoing diagnostic cardiac catheterization.

Investigation of the dosimetric characteristics of radiophotoluminescent glass dosimeter for high-energy photon beams

ABSTRACTThe aim of this work was to investigate the dosimetric characteristics of radiophotoluminescent glass dosimeter (RPLGD) for high energy photon beams in both flattening filter mode and flatt...

Radiation Exposure in Computed Tomography Localizer Radiograph

This research measured the radiation exposure of the computed tomography(CT) localizer radiograph of the trunk of the body. The entrance surface dose for CT localizer radiograph was measured using radiophotoluminescent glass dosimeter(RPLD) on four points of measurement, including the center of the phantom, on the surface of a phantom placed in the center of a CT bed, assuming that the subject has a thickness of 20 cm. The entrance surface dose of the localizer radiograph under the chest CT protocol manufacturer's initial setting conditions of 120 kV 35 mA was 0.80 mGy at the center and 0.53 for the 4-location average for the upper X-ray tube (excluding the CT bed), and 0.74 mGy at the center and 0.48 mGy for the 4-location average for the lower X-ray tube (including the CT bed). Compared to the Japan DRLs 2015 chest X-ray (P→A), the entrance surface dose was 2.67 times at the center and 1.77 times for the 4-location average for the upper X-ray tube and 2.47 times at the center and 1.60 times for the 4-location average for the lower X-ray tube. The CT radiation dose also cannot be ignored for the localizer radiograph entrance surface dose.

Influence of Bowtie Filter and Patient Positioning on In-plane Dose Distribution and Image Quality in ECG-gated CT

In electrocardiographic (ECG)-gated computed tomography (CT) for diagnosis of cardiac diseases, radiation dose and image quality are optimized by limiting field of view (FOV) and centering on the heart. However, it is necessary to set wide FOV with large bowtie filter depending on patient positioning or various diagnoses such as aortic diseases. The purpose of this study is to clarify influence of bowtie filter and patient positioning on in-plane dose distribution, organ-absorbed dose, image quality in ECG-gated CT. In-plane dose distribution and organ-absorbed dose were evaluated with radio photoluminescence glass dosimeters, and signal-to-noise ratio (SNR) were measured for evaluation of image quality. The bowtie filter was used small (S) and large (L). With automatic exposure control, volume computed tomography dose index was 55.3 mGy at S and 71.8 mGy at L. The phantom was positioned on the heart of phantom (Heart) and the center of phantom (Body). In Heart-L compared with Heart-S, organ-absorbed dose was 1.29 times at breasts. In Heart-S compared with Body-S, in-plane dose distribution was increased 25% at left anterior and decreased 20% at right posterior. In SNR, S and L were decreased from 50 mm off-center. To set appropriate bowtie filter and positioning was reduced radiation dose and improved image quality in ECG-gated CT.

Energy dependence of a radiophotoluminescent glass dosimeter for HDR 192 Ir brachytherapy source.

We determined correction factors for absorbed dose energy dependence and intrinsic energy dependence for measurements of absorbed dose to water around an 192 Ir source using a radiophotoluminescent glass dosimeter (RPLD) calibrated with a 4-MV photon beam. The ratio of the absorbed dose to the water and the average absorbed dose to RPLD for the 192 Ir beam relative to the same ratio in a 4MV photon beam defines the absorbed dose energy dependence and was determined at distances of 2-10cm (at intervals of 1cm) from the 192 Ir source in a water phantom using the egs_chamber user code. The RPLD was calibrated to measure absorbed dose to water, Dw , in a 4MV photon beam using an ionization chamber, which was also used to measure absorbed dose to water, Dw , in a water phantom using the 192 Ir source. The detector response radiophotoluminescence (RPL signal per average absorbed dose in the detector) in the 192 Ir beam relative to that in the 4MV photon beam (the relative intrinsic efficiency) was determined experimentally. Finally, the beam quality correction factor was obtained as the quotient between the absorbed dose energy dependence and the relative intrinsic efficiency and corrects for the difference between the beam quality Q0 used at calibration and the beam quality Q used in the measurements. The relative dose ratio of the average absorbed dose to water relative to RPLD ranged from 0.930 to 0.746, and the beam quality correction factor ranged from 0.999 to 0.794 for distances of 2-10cm from the 192 Ir source. The relative detector response to an 192 Ir source and a 4-MV photon beam was 0.930, and it did not vary significantly with distance. These results demonstrate that corrections for absorbed dose energy dependence and intrinsic energy dependence are required when using an RPLD to measure with sources different from the reference source providing the primary calibration.

Energy response of FD-7 RPL glass dosimeter compared with LiF Mg, Ti and Al2003:C dosimeters

The aim of this study was to compare the energy dependence of Radio-Photoluminescent Glass Dosimeter (RPLGD) with thermoluminescent LiF:Mg,Ti (TLD-100) and Optically stimulated luminescent (Al2O3:C) dosimeters. In this work, a Monte Carlo simulation with MCNP5 was carried out to estimate the energy responses of these dosimeters. The following common clinical radiation qualities were applied: 50–300 kVp X-rays, 4–20 MeV electron beam and 60Co γ rays as the reference. The current study is compared to previous measurements and MC simulation in literature. For kilovoltage photon beams, the dosimeters displayed an increasing response with decreasing energy with a significant over response factor at 70 kVp of RPLGD and Al2O3:C about 4.39 and 3.40 respectively, and a maximum of about 1.40 for TLD-100. For electron beams were found to be with a maximum of 5.1% and 3.5% for RPLGD and TLD-100 dosimeters respectively, for OSLD a maximum of 6% in 6–20 MeV and 11% at 4 MeV. This paper has clearly confirmed that all three dosimeters should be used with an energy compensation filter in low energy X-ray (<250 kV). All studied dosimeters are recommended for clinical and experimental use particularly in radiotherapy.

Clinical Implementation of an In vivo Dose Verification System Based on a Transit Dose Calculation Tool for 3D-CRT

We developed and evaluated an algorithm to calculate the target radiation dose in cancer patients by measuring the transmitted dose during 3D conformal radiation treatment (3D-CRT) treatment. The patient target doses were calculated from the transit dose, which was measured using a glass dosimeter positioned 150 cm from the source. The accuracy of the transit dose algorithm was evaluated using a solid water phantom for five patient treatment plans. We performed transit dose-based patient dose verification during the actual treatment of 34 patients who underwent 3D-CRT. These included 17 patients with breast cancer, 11 with pelvic cancer, and 6 with other cancers. In the solid water phantom study, the difference between the transit dosimetry algorithm with the treatment planning system (TPS) and the measurement was −0.10 ± 1.93%. In the clinical study, this difference was 0.94 ± 4.13% for the patients with 17 breast cancers, −0.11 ± 3.50% for the eight with rectal cancer, 0.51 ± 5.10% for the four with bone cancer, and 0.91 ± 3.69% for the other five. These results suggest that transit-dosimetry-based in-room patient dose verification is a useful application for 3D-CRT. We expect that this technique will be widely applicable for patient safety in the treatment room through improvements in the transit dosimetry algorithm for complicated treatment techniques (including intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT)).

Comparative Study of the Effective Dose from Panoramic Radiography in Dentistry Measured Using a Radiophotoluminescent Glass Dosimeter and an Optically Stimulated Luminescence Detector

Accurate measurement of the absorbed dose and the effective dose is required in dental panoramic radiography involving relatively low energy with a rotational X-ray tube system using long exposures. To determine the effectiveness of measuring the irradiation by using passive dosimetry, we compared the entrance skin doses by using a radiophotoluminescent glass dosimeter (RPL) and an optically stimulated luminescence detector (OSL) in a phantom model consisting of nine and 31 transverse sections. The parameters of the panoramic device were set to 80 kV, 4 mA, and 12 s in the standard program mode. The X-ray spectrum was applied in the same manner as the panoramic dose by using the SpekCalc Software. The results indicated a mass attenuation coefficient of 0.008226 cm2/g, and an effective energy of 34 keV. The equivalent dose between the RPL and the OSL was calculated based on a product of the absorbed doses. The density of the aluminum attenuators was 2.699 g/cm3. During the panoramic examination, tissue absorption doses with regard to the RPL were a surface dose of 75.33 μGy and a depth dose of 71.77 μGy, those with regard to the OSL were surface dose of 9.2 μGy a depth dose of 70.39 μGy and a mean dose of 74.79 μGy. The effective dose based on the International Commission on Radiological Protection Publication 103 tissue weighting factor for the RPL were 0.742 μSv, 8.9 μSv, 2.96 μSv and those for the OSL were 0.754 μSv, 9.05 μSv, and 3.018 μSv in the parotid and sublingual glands, orbit, and thyroid gland, respectively. The RPL was more effective than the OSL for measuring the absorbed radiation dose in low-energy systems with a rotational X-ray tube.

Impact of testicular shielding in liposarcoma to scrotum by using radio-photoluminescence glass dosimeter (RPLGD): a case report.

Radiation protection in the scrotum to reduce the risk of genetic effect in the future is very important. This study aimed to measure the scrotal dose outside the treatment fields by using the radio-photoluminescence glass dosimeter (RPLGD). The characteristics of RPLGD model GD-302M were studied. Scattered dose to scrotum was measured in one liposarcoma case with the prescribed dose of 60 Gy. RPLGDs were placed in three different locations: one RPLGD was positioned at the posterior area which closer to the scrotum, and the other two RPLGDs were placed between the penis and the scrotum. Three RPLGDs were employed in each location. The scattered doses were measured in every fraction during the whole course of treatment. The entire number of 100 RPLGDs showed the uniformity within ±2%. The signal from RPLGD demonstrated linear proportion to the radiation dose (r = 0.999). The relative energy response correction factor was 1.05. The average scrotal dose was 4.1 ± 0.9 cGy per fraction. The results presented a wide range since there was a high uncertainty during RPLGD placement. The total scrotal dose for the whole course of treatment was 101.9 cGy (1.7% of the prescribed dose). The RPLGD model GD-302M could be used to measure scattered dose after applying the relative energy correction factor.

Evaluation of effective dose during X-ray training in a radiological technology program in Korea

The objective of this study was to evaluate the potential risks encountered during X-ray training in radiology education. 10 exposure scenarios were selected by interviewing the radiation experts who they are professors having roles in the X-ray training. Fourteen organ doses and 13 tissues (weighted per ICRP 103 Publication) were measured with glass dosimeters (GD-352M) and a Rando phantom. Of 270 total organ doses (27 tissues with 10 projection methods) measured, 162 organ doses (60%) were <0.3 mSv; 206 organ doses (76.3%) were <1 mSv. The cumulative effective doses of 10 projection methods resulted in 5.71 mSv, after consideration of tissue weighting factors. Except in human radiography for education purposes, radiation exposure risk is low. The procedure is dangerous to the human body undergoing radiography, so the risk is not justified.

Glow curve analysis of glassy system dosimeter subjected to photon and electron irradiations

Abstract The current paper illustrates glow curve analysis of newly developed Borate glass dosimeters. A series of dosimetric properties including dose response for photons and electrons, energy response, optical fading, and precision were determined. Glow curve deconvolution based on the general order kinetics equation was applied to extract the trapping parameters. Excellent fitting was obtained with the superposition of three-second order glow peaks. The quality of fitting was monitored through the r2 value which is always in excess of 0.9998. Thermoluminescence (TL) measurements showed that the material exhibits good linear dose–response over the delivered range of absorbed dose from 0.5 to 4 Gy for photons and electrons irradiation with low energy dependence. The material exhibits large signal loss when exposed to direct sunlight and moderate signal loss when exposed to fluorescent light. Therefore, it is recommended to use the current dosimeters indoor and to avoid prolonged direct exposure to fluorescent light. This combination of properties makes the material suitable for radiation dosimetry.

VALIDATION OF MONTE CARLO DOSE CALCULATION FOR PAEDIATRIC CT EXAMINATIONS USING TUBE CURRENT MODULATION BASED ON IN-PHANTOM DOSIMETRY.

The aim of this study is to estimate tube current modulation (TCM) profiles in paediatric computed tomography (CT) examinations with a TCM scheme (Volume-EC) and evaluate the estimation accuracy of TCM profiles. Another aim is to validate organ doses calculated using Monte Carlo-based CT dosimetry software and estimated TCM profiles by comparing them with those measured using 5-year-old and 10-year-old anthropomorphic phantoms and radio-photoluminescence glass dosemeters. Dose calculations were performed by inputting detailed descriptions of a CT scanner, scan parameters and CT images of the phantoms into the software. Organ doses were evaluated from the calculated dose distribution images. Average relative differences (RDs) between the estimated and actual TCM profiles ranged from -3.6 to 5.6%. RDs between the calculated and measured organ doses ranged from -4.2 to 13.0% and -18.1 to 4.9% for 5-year-old and 10-year-old phantoms, respectively. These results validate dose calculations for paediatric CT scans using TCM.

DEVELOPMENT OF RADIATION DOSE CALCULATION SOFTWARE USING THE SIZE-SPECIFIC DOSE ESTIMATE.

We aimed to develop a software for facilitating absorbed dose per pixel (pixel dose) calculation using a size-specific dose estimate (SSDE). We calculated the pixel dose at nine equal points inserted into the radiophotoluminescence glass dosemeter (RPLD) and compared the pixel dose with the measured doses using RPLD. With this method, the relative errors of average pixel dose was -0.1% for adults and 2.86, 3.36 and 1.17% for those aged 10, 5 and 1 years without tube current modulation, respectively. In contrast, the relative error of SSDE was 17.37% for adults and 20.38, 20.73 and 19.20% for those aged 10, 5 and 1 years, respectively. In other words, the pixel dose was almost equal to the measured doses. Therefore, our software can be useful for determining arbitrary point.

Applicability of Glass Dosimeters for In-vivo Dosimetry in Brachytherapy

During brachytherapy, confirming the dose delivered is very important in order to prevent radiation-associated side effects. Therefore, we aimed to confirm the accuracy of dose delivery near the source by inserting glass dosimeters within the applicator. We created an alternative pelvic phantom with the same shape and internal structures as the usual patient. In addition, we created a tandem for insertion of the glass dosimeters and measured the dose near the source by inserting the glass dosimeters into the tandem and evaluating the accuracy of the dwell position and time through the dose near the source. Errors between the values obtained from the five glass dosimeters and the values from the treatment planning system were −6.27, −2.1, −4.18, 6.31, and −0.39%, respectively. The mean error was 3.85%. This value was acceptable considering that the error of the glass dosimeter itself is approximately 3%. Even though a complement of the applicator and the error calibration is required in order to apply this technique clinically, we believe that radiation accidents and overdoses can be prevented through in-vivo dosimetry using a glass dosimeter for brachytherapy.