[Association between insomnia and type 2 diabetes: A two-sample Mendelian rando-mization study].

OBJECTIVE: To explore the robust relationship between insomnia and type 2 diabetes mellitus by two-sample Mendelian randomization analysis to overcome confounding factors and reverse causality in observational studies. METHODS: We identified strong, independent single nucleotide polymorphisms (SNPs) of insomnia from the most up to date genome wide association studies (GWAS) within European ancestors and applied them as instrumental variable to GWAS of type 2 diabetes mellitus. After excluding SNPs that were significantly associated with smoking, physical activity, alcohol consumption, educational attainment, obesity, or type 2 diabetes mellitus, we assessed the impact of insomnia on type 2 diabetes mellitus using inverse variance weighting (IVW) method. Weighted median and MR-Egger regression analysis were also conducted to test the robustness of the association. We calculated the F statistic of the selected SNPs to test the applicability of instrumental variable and F statistic over than ten indicated that there was little possibility of bias of weak instrumental variables. We further examined the existence of pleiotropy by testing whether the intercept term in MR-Egger regression was significantly different from zero. In addition, the leave-one-out method was used for sensitivity analysis to verify the stability and reliability of the results. RESULTS: We selected 248 SNPs independently associated with insomnia at the genome-wide level (P<5×10-8) as a preliminary candidate set of instrumental variables. After clumping based on the reference panel from 1000 Genome Project and removing the potential pleiotropic SNPs, a total of 167 SNPs associated with insomnia were included as final instrumental variables. The F statistic of this study was 39. 74, which was in line with the relevance assumption of Mendelian randomization. IVW method showed insomnia was associated with higher risk of type 2 diabetes mellitus that po-pulation with insomnia were 1. 14 times more likely to develop type 2 diabetes mellitus than those without insomnia (95% CI: 1.09-1.21, P<0.001). The weighted median estimator (WME) method and MR-Egger regression showed similar causal effect of insomnia on type 2 diabetes mellitus. And MR-Egger regression also showed that the effect was less likely to be triggered by pleiotropy. Sensitivity analyses produced directionally similar estimates. CONCLUSION: Insomnia is a risk factor of type 2 diabetes mellitus, which has positively effects on type 2 diabetes mellitus. Our study provides further rationale for indivi-duals at risk for diabetes to keep healthy lifestyle.

Effective dose and radiation risk under 640-slice abdominal computed tomography examination without contrast medium injection.

BACKGROUND: Medical imaging plays a crucial role in modern medicine. In order to provide fast and accurate medical diagnosis, computed tomography (CT) is a commonly used tool in radiological examinations, and 640-slice CT is the most advanced CT imaging modality. OBJECTIVE: To evaluate the radiation dose and the risk under 640-slice abdominal CT examination. METHODS: Examinations were performed using a 640-slice CT scanner on an Alderson-Rando anthropomorphic phantom. The used scanning acquisition parameters were the same as those used on abdominal examination without contrast medium injection in clinical practice. To measure the absorbed doses, optically stimulated luminescence dosimeters (OSLDs) were put into liver, stomach, bladder, gonads, colon, small intestine, bone marrow, and skin. RESULTS: According to the 1990 Recommendations of the International Commission on Radiological Protection (ICRP Publication 60), the calculated effective doses received from this examination were 0.90 mSv in males and 0.89 mSv in females. According to the 2007 Recommendations of the International Commission on Radiological Protection (ICRP Publication 103), the calculated effective dose received from this examination was 0.83 mSv in both sexes. CONCLUSIONS: Radiation doses obtained from the abdominal 640-slice CT examination are lower than the yearly cumulative doses received from natural radiation, revealing there is no deterministic effect and radiation risk is relatively low; therefore, this CT examination is considered safe.

A Simplified Model for Optical Systems with Random Phase Screens.

A first-order optical system with arbitrary multiple masks placed at arbitrary positions is the basic scheme of various optical systems. Generally, masks in optical systems have a non-shift invariant (SI) effect; thus, the individual effect of each mask on the output cannot be entirely separated. The goal of this paper is to develop a technique where complete separation might be achieved in the common case of random phase screens (RPSs) as masks. RPSs are commonly used to model light propagation through the atmosphere or through biological tissues. We demonstrate the utility of the technique on an optical system with multiple RPSs that model random scattering media.

Evaluation of patient organ doses from kilovoltage cone-beam CT imaging in radiation therapy.

BACKGROUND: Currently, CBCT system is an indispensable component of radiation therapy units. Because of that, it is important in treatment planning and diagnosis. CBCT is also an crucial tool for patient positioning and verification in image-guided radiation therapy (IGRT). Therefore, it is critical to investigate the patient organ doses arising from CBCT imaging. The purpose of this study is to evaluate patient organ doses and effective dose to patients from three different protocols of Elekta Synergy XVI system for kV CBCT imaging examinations in image guided radiation therapy. MATERIALS AND METHODS: Organ dose measurements were done with thermoluminescent dosimeters in Alderson RA NDO male phantom for head & neck (H&N), chest and pelvis protocols of the Elekta Synergy XVI kV CBCT system. From the measured organ dose, effective dose to patients were calculated according to the International Commission on Radiological Protection 103 report recommendations. RESULTS: For H&N, chest and pelvis scans, the organ doses were in the range of 0.03-3.43 mGy, 6.04-22.94 mGy and 2.5-25.28 mGy, respectively. The calculated effective doses were 0.25 mSv, 5.56 mSv and 4.72 mSv, respectively. CONCLUSION: The obtained results were consistent with the most published studies in the literature. Although the doses to patient organs from the kV CBCT system were relatively low when compared with the prescribed treatment dose, the amount of delivered dose should be monitored and recorded carefully in order to avoid secondary cancer risk, especially in pediatric examinations.

[Systematic review and Meta-analysis of efficacy and safety of Xiangsha Yangwei Pills in treatment of chronic gastritis].

To systematically evaluate the efficacy and safety of Xiangsha Yangwei Pills in the treatment of chronic gastritis. Compu-ter retrieval was performed for Cochrane Library, Medline, EMbase, China Knowledge Network Database(CNKI), China Biomedical Literature Service System(SinoMed), Chongqing Weipu Chinese Science and Technology Journal Database(VIP) and WanFang Database(WanFang) randomized controlled trials about Xiangsha Yangwei Pills combined with Western medicine in the treatment of chro-nic gastritis. The retrieval time ranged from the establishment of the library to April 26, 2019. Meta-analysis was performed by RevMan 5.3 software after two independent researchers conducted literature screening, data extraction and quality evaluation according to inclusion and exclusion criteria. A total of 1 720 patients were enrolled in 18 RCT. According to the classification of chronic gastritis, they were divided into three subgroups: chronic gastritis, chronic atrophic gastritis and chronic superficial gastritis. The results of Meta-ana-lysis showed that the efficacy of Xiangsha Yangwei Pills combined with Western medicine in treating chronic gastritis was higher than that of Western medicine. As for the recurrence rate, Xiangsha Yangwei Pills combined with Western medicine was lower than Western medicine. And there was no statistical difference about helicobacter pylori(Hp) eradication rate between Xiangsha Yangwei Pills combined with Western medicine as well as Western medicine. In terms of the incidence of adverse reactions, Xiangsha Yangwei Pills combined with Western medicine was lower than Western medicine, and no serious adverse reaction was reported. The results of this systematic review showed that compared with the conventional Western medicine group, Xiangsha Yangwei Pills combined with Western medicine can significantly alleviate clinical symptoms of chronic gastritis, with fewer adverse reactions. However, due to the low methodological quality of the included studies and the reliability of the impact conclusions, high-quality multi-center, large-sample, randomized, double-blind controlled trials are needed for validation.

Comparison of measured and calculated doses in a Rando phantom with a realistic lung radiotherapy treatment plan including heterogeneities.

In this work, dose measurements were performed to evaluate an external radiotherapy treatment plan and, particularly, to validate dose calculations for a lung lesion case. Doses were calculated by the Varian Eclipse treatment planning system using the AAA anisotropic analytical algorithm. The measurements were performed using a Rando anthropomorphic phantom and TLD700 thermoluminescent dosimeters. The comparison between doses calculated and doses measured by means of thermoluminescence (TL) shows compatibility except for a few points, due to the limitations in the heterogeneity correction used for the case studied here. The deviation between the calculated and measured doses is about 6.5% for low (< 0.5 Gy) doses and about 1% for higher doses (> 0.5 Gy).The deviation between AAA-calculated and TL-measured doses was also found to be higher in proximity to heterogeneous tissue interfaces.

Do sleep hygiene measures and progressive muscle relaxation influence sleep bruxism? Report of a randomised controlled trial.

The aim of this study was to assess the effects of sleep hygiene measures combined with relaxation techniques in the management of sleep bruxism (SB) in a double-blind, parallel, controlled, randomised clinical trial design. Sixteen participants (mean ± s.d. age = 39·9 ± 10·8 years) were randomly assigned to a control group (n = 8) or to the experimental treatment group (n = 8). Participants belonging to the latter group were instructed to perform sleep hygiene measures and progressive muscle relaxation techniques for a 4-week period. Two polysomnographic recordings, including bilateral masseter electromyographic activity, were made: one prior to the treatment and the other after the treatment period. The number of bruxism episodes per hour, the number of burst per hour and the bruxism time index (i.e. the percentage of total sleep time spent bruxing) were established as outcome variables. No significant differences could be observed between the outcome measures obtained before and after the 4-week period, neither for the sleep bruxism variables nor for the sleep variables. Within the limitations of this study, it was concluded that there is no effect of sleep hygiene measures together with progressive relaxation techniques on sleep bruxism or sleep over a 4-week observation period.

In-depth exploration of the radiation exposure to staff performing endoscopic retrograde cholangiopancreatography procedures (ERCP) through RANDO phantom and TLDs.

This study provides a comprehensive evaluation of the occupational radiation exposure faced by healthcare professionals during Endoscopic Retrograde Cholangiopancreatography (ERCP) procedures. Utilizing an anthropomorphic RANDO phantom equipped with Thermoluminescent Dosimeters (TLDs), we replicated ERCP scenarios to measure radiation doses received by medical staff. The study meticulously assessed radiation exposure in various corresponding body regions typically occupied by medical staff during ERCP, with a focus on eyes, thyroid, hands, and reproductive corresponding organ regions. The findings revealed significant variations in radiation doses across different body parts, highlighting areas of higher exposure and underscoring the need for improved protective measures and procedural adjustments. The effective radiation doses were calculated using standard protocols, considering the varying levels of protection offered by lead aprons and thyroid shields. The results demonstrate the substantial radiation exposure experienced by healthcare staff, particularly in regions not adequately shielded. This study emphasizes the necessity for enhanced radiation safety protocols in clinical settings, advocating for advanced protective equipment, training in radiation safety, and the exploration of alternative imaging modalities. The findings have crucial implications for both patient and staff safety, ensuring the continued efficacy and safety of ERCP and similar interventional procedures. This research contributes significantly to the field of occupational health and safety in interventional radiology, providing vital data for the development of safer medical practices.

Radiation Exposure and Safety Considerations in Interventional Radiology: Comparison of a Twin Robotic X-ray System to a Conventional Angiography System.

Background/Objectives: To evaluate radiation exposure in standard interventional radiology procedures using a twin robotic X-ray system compared to a state-of-the-art conventional angiography system. Methods: Standard interventional radiology procedures (port implantation, SIRT, and pelvic angiography) were simulated using an anthropomorphic Alderson RANDO phantom (Alderson Research Laboratories Inc. Stamford, CT, USA) on an above-the-table twin robotic X-ray scanner (Multitom Rax, Siemens Healthineers, Forchheim, Germany) and a conventional below-the-table angiography system (Artis Zeego, Siemens Healthineers, Forchheim, Germany). The phantom's radiation exposure (representing the potential patient on the procedure table) was measured with thermoluminescent dosimeters. Height-dependent dose curves were generated for examiners and radiation technologists in representative positions using a RaySafe X2 system (RaySafe, Billdal, Sweden). Results: For all scenarios, the device-specific dose distribution differs depending on the imaging chain, with specific advantages and disadvantages. Radiation exposure for the patient is significantly increased when using the Multitom Rax for pelvic angiography compared to the Artis Zeego, which is evident in the dose progression through the phantom's body as well as in the organ-related radiation exposure. In line with these findings, there is an increased radiation exposure for the performing proceduralist, especially at eye level, which can be significantly minimized by using protective equipment (p < 0.001). Conclusions: In this study, the state-of-the-art conventional below-the-table angiography system is associated with lower radiation dose exposures for both the patient and the interventional radiology physician compared to an above-the-table twin robotic X-ray system for pelvic angiographies. However, in other clinical scenarios (port implantation or SIRT), both devices are suitable options with acceptable radiation exposure.

[Effect of transcutaneous electrical acupoint stimulation combined with auricular acupressure on sexual hormone level and gonadal development in girls with precocious puberty].

OBJECTIVE: To explore the effect of transcutaneous electrical acupoint stimulation (TEAS) combined with auricular acupressure on serum sexual hormone level, and the ovarian, follicular and uterine development in the girls with precocious puberty. METHODS: Sixty girls with precocious puberty were randomly divided into a control group (30 cases, 2 cases dropped off) and a treatment group (30 cases, 3 cases dropped off). In both the control group and the treatment group, the healthy life-style intervention was provided for 12 weeks. Besides, in the treatment group, TEAS was delivered for 20 minutes each time, twice a week; and bilateral auricular acupressure was combined. The duration of treatment was 12 weeks. The levels of serum luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol (E2), as well as ovarian volume, maximum follicular diameter and uterine volume before and after treatment were detected, and the safety was evaluated separately. RESULTS: Compared with before treatment, the contents of serum LH and FSH were increased (P<0.05), and the ovarian volume and the maximum follicle diameter were increased (P<0.05) in the control group after treatment; the contents of serum FSH and E2 were decresed (P<0.05), and the maximum follicular diameter was reduced significantly (P<0.05) in the treatment group after treatment. Compared with the control group, the contents of serum LH, FSH and E2 were decreased (P<0.05), while the ovarian volume and the maximum follicle diameter were decreased (P<0.05) in the treatment group after treatment. CONCLUSION: TEAS combined with auricular acupressure can effectively decrease the level of sex hormone, improve the ovarian and uterine development and retard the gonadal development. Such combined therapy is of high safety and conductive to regulating the development for the girls with precocious puberty.

Evaluating dose distributions of normal organs for patients undergoing VMAT therapy of nasopharyngeal carcinoma using Rando phantom and TLD-100H.

BACKGROUND: The routine radiation therapy treatment planning does not include secondary radiation and peripheral doses resulting from radiotherapy exposure in patients with nasopharyngeal carcinoma (NPC) undergoing Volumetric Modulated Arc Therapy (VMAT) using an linear accelerator (linac) of Axesse (Elekta 2538). OBJECTIVE: VMAT has a better dose conformity of the tumor and is also operated by adjusting the shapes of mulileaf collimator. However, such treatment is potentially important to improve the accuracy of estimated health risks. METHODS: This study aimed to evaluate the equivalent dose of organ or tissue (DT) and effective dose (E) for normal organs using the Alderson Rando phantom as an equivalent of the human body. Thermoluminescent dosimeters (TLD-100H) were calibrated by 6 MV X-ray originated by the linac. A total of 252 TLDs were used. These TLDs were inserted into phantom organ or tissue which closely approximated to these places. RESULTS: The thyroid dose (D𝑡ℎ𝑦) had the highest dose, 1840 ± 202 mSv/treatment. The E of the Rando was 7.11 ± 0.61 mSv/treatment, as estimated using ICRP 103. The skin doses (D𝑠𝑘𝑖𝑛) varied significantly outside the treatment field and decreased as the distance from the treatment field increased. CONCLUSIONS: This study can be referred to practical guidance regarding radiation protections of the public.

Comparison of Monaco treatment planning system algorithms and Monte Carlo simulation for small fields in anthropomorphic RANDO phantom: The esophagus case.

BACKGROUND: In this study, the dose distributions obtained by the algorithms used in Monaco treatment planning system (TPS) and Monte Carlo (MC) simulation were compared for small fields in the anthropomorphic RANDO phantom, and then, the results were analyzed using the gamma analysis method. MATERIALS AND METHODS: In the study, dose distributions obtained from the collapse cone algorithm, MC algorithm, and MC simulation were examined. The EGSnrc was utilized for MC simulation. RESULTS: In radiation fields smaller than 3 cm × 3 cm, the doses calculated by the CC algorithm are particularly high in the region of lung/soft-tissue interfaces. In the region of soft-tissue/vertebral interfaces, the doses calculated by the CC algorithm and the MC algorithm are compatible with the MC simulation. For each algorithm, the main reason for the non-overlapping dose curves in small fields compared to MC simulation is that the lateral electronic equilibrium loss is not taken into account by the algorithms. CONCLUSION: The doses calculated by the algorithms used in TPS may differ, especially in environments where density changes are sharp. Even if the radiation dose from different angles is calculated similarly in the target area by the algorithms, the calculated doses in the tissues in each radiation field path may be different. Therefore, to increase the quality of radiotherapy and to protect critical organs more accurately, the accuracy of the algorithms in TPS should be checked before treatment, especially in multi-field treatments such as stereotactic body radiation therapy and intensity-modulated radiotherapy for tumors in the abdominal region.

Measurement of Entrance Skin Dose and the Dose Received by Different Organs in Panoramic Dental Imaging.

BACKGROUND: Thermoluminescence dosimetry(TLD) has been known as one of the most effective methods for dose estimation in diagnostic radiology. Orthopantomogram (OPG) imaging is used by many dentists, oral and maxillofacial surgeons as an effective tool for choosing an appropriate treatment plan. OBJECTIVE: This study aims to measure the entrance skin dose and the dose values received by different head and neck organs in OPG imaging using TLD dosimeters (TLD-100). MATERIAL AND METHODS: In this experimental study, the entrance skin dose and doses of various organs during imaging were measured by TLD dosimeters inside and on the surface of the Rando-Phantom. Doses to various organs, including thyroid, eye, esophagus, parotid and sublingual and submandibular salivary glands were measured. The measurements were repeated twice, and the dose values obtained in the two steps were compared. RESULTS: Based on the results obtained in this study, the minimum dose values were found in Esophagus; 65.81, and 59.31 µGy, respectively. The maximum organ dose value was found for left parotid glands, 3842.42, and 3399.58 for the two measurements, respectively. CONCLUSION: The results show that the dose values can vary based on devices, exposure conditions, and TLD positioning.

Radiation doses with various body weights of phantoms in brain 128-slice MDCT examination.

The effective dose (HE) and organ or tissue equivalent dose (HT) for use in brain computed tomography (CT) examinations with various body weights were evaluated. Thermoluminescent dosimeters (TLD-100H) were inserted into Rando and five anthropomorphic phantoms. These phantoms were made of polymethylmethacrylate (PMMA), according to the specifications of ICRU 48, with masses from 10 to 90 kg. Brain CT examinations were conducted, scanning the maxillae from the external auditory meatus to the parietal bone using a 128-slice multi-detector CT (MDCT) scanner. To reduce errors, three independent trials were conducted. Calculated HE,TLD, based on the weighting factor recommended by ICRP 103, was 1.72 ± 0.28 mSv, which slightly exceeds the HE,DLP of 1.70 mSv, that was calculated from the dose-length product (DLP) of the Rando phantom. This experiment yielded HE,TLD values of ICRP 103 from the highest 1.85 ± 0.28 (90 kg) to the lowest 1.47 ± 0.22 (10 kg) mSv. HE,TLD (mSv) = 5.45×10-3 W(kg) + 1.361, with an R2 of 0.87667. Using the DLP protocol, HE,DLP was estimated from CTDIvol that was recorded directly from the console display of the CT unit and multiplied by the conversion coefficient (k) recommended by the ICRP 103. Finally, the experimental results obtained herein are compared with those in the literature. Physicians should choose and adjust protocols to prevent the exposure of patients to unnecessary radiation, satisfying the as low as reasonably achievable (ALARA) principle. These findings will be valuable to patients, physicians, radiologists and the public.

Evaluation of Breast Cancer Radiation Therapy Techniques in Outfield Organs of Rando Phantom with Thermoluminescence Dosimeter.

BACKGROUND: Given the importance of scattered and low doses in secondary cancer caused by radiation treatment, the point dose of critical organs, which were not subjected to radiation treatment in breast cancer radiotherapy, was measured. OBJECTIVE: The purpose of this study is to evaluate the peripheral dose in two techniques of breast cancer radiotherapy with two energies. MATERIAL AND METHODS: Eight different plans in two techniques (conventional and conformal) and two photon energies (6 and 15 MeV) were applied to Rando Alderson Phantom's DICOM images. Nine organs were contoured in the treatment planning system and specified on the phantom. To measure the photon dose, forty-eight thermoluminescence dosimeters (MTS700) were positioned in special places on the above nine organs and plans were applied to Rando phantom with Elekta presice linac. To obtain approximately the same dose distribution in the clinical organ volume, a wedge was used on planes with an energy of 6 MeV photon. RESULTS: Point doses in critical organs with 8 different plans demonstrated that scattering in low-energy photon is greater than high-energy photon. In contrast, neutron contamination in high-energy photon is not negligible. Using the wedge and shield impose greater scattering and neutron contamination on patients with low-and high-energy photon, respectively. CONCLUSION: Deciding on techniques and energies required for preparing an acceptable treatment plan in terms of scattering and neutron contamination is a key issue that may affect the probability of secondary cancer in a patient.

A comparison of the doses received by normal cranial tissues during different simple model conventional radiotherapeutic approaches to pituitary tumours.

This aim of this study was to compare the doses received by critical cranial organs when three different radiation techniques were used to treat pituitary tumours. Cranial computed tomography scans of a RANDO phantom and 30 patients were used for pituitary macroadenoma radiotherapy treatment planning. For each slice, target volumes and other critical organs were contoured and three techniques were applied: (A) two parallel-opposed lateral fields, (B) two oblique fields (45°) in coronal plane and (C) two parallel-opposed lateral and anterior fields while the head was tilted 45° in the sagittal plane. The doses received by the target volume and the critical organs for each technique were calculated for all patients. Irradiation was repeated three times for each technique. Finally, the doses that reached the organs of interest resulting from these techniques were compared. The dose delivered to the temporal lobes was 105, 9 and 72 % of the prescribed dose using techniques A, B and C, respectively. The dose received by the cochlea was the lowest in technique C (27 % of prescribed dose) compared with techniques A (79 %) and B (48 %). All techniques delivered 100 % of the prescribed dose to the chiasma. Technique A increased the dose to temporal lobes and the cochlea to such an extent that they exceeded the tolerance dose. Technique B spared the temporal lobes better than technique C; however, technique C was preferred since the dose received by the cochlea in this case was the lowest of all techniques. None of the techniques spared the chiasma.

[Relaxing needling combined with rehabilitation training for medial collateral ligament injury of knee joint].

OBJECTIVE: To compare the clinical efficacy differences between relaxing needling combined with rehabilitation training and rehabilitation training alone for medial collateral ligament (MCL) injury of knee joint. METHODS: Sixty cases of MCL injury were randomly assigned into an observation group (30 cases, one case dropping out) and a control group (30 cases, two cases dropping out). Patients in the control group were treated with rehabilitation training; based on the treatment of control group, patients in the observation group were additionally treated with relaxing needles at ashi points, Heding (EX-LE 2), Neixiyan (EX-LE 4), Dubi (ST 35), Yanglingquan (GB 34), Liangqiu (ST 34), etc. The treatment was given once a day; six treatments were taken as one course, and totally four courses were given. The visual analogue scale (VAS), Lysholm knee function score and clinical efficacy before and after treatment were evaluated; also the safety was evaluated. RESULTS: After treatment, VAS scores were apparently reduced and the Lysholm scores were obviously increased in the two groups (all P<0.001). The improvement of VAS and Lysholm scores in the observation group were superior to that in the control group (both P<0.05). The effective rate was 93.1% (27/29) in the observation group, which was superior to 71.4% (20/28) in the control group (P<0.05). During the treatment, no adverse events occurred in the two groups. CONCLUSIONS: Relaxing needling combined with rehabilitation training can effectively improve the swel-ling, pain and other symptoms of MCL injury, which is superior to rehabilitation training alone.

Image quality and effective dose of a robotic flat panel 3D C-arm vs computed tomography.

BACKGROUND: The aim of this study was to determine the effective dose and corresponding image quality of different imaging protocols of a robotic 3D flat panel C-arm in comparison to computed tomography (CT). METHODS: Dose measurements were performed using a Rando-Alderson Phantom. The phantom was exposed to different scanning protocols of the 3D C-arm and the CT. Pedicle screws were inserted in a fresh swine cadaver. Images were obtained using the same scanning protocols. RESULTS: At the thoracolumbar junction, the effective dose was comparable for 3D high-dose protocols, with (4.4 mSv) and without (4.3 mSv) collimation and routine CT (5 mSv), as well as a dose-reduction CT (4.0 mSv). A relevant reduction was achieved with the 3D low-dose protocol (1.0 mSv). Focusing on Th6, a similar reduction with the 3D low-dose protocol was achieved. The image quality of the 3D protocols using titanium screws was rated as 'good' by all viewers, with excellent correlation. CONCLUSIONS: Modern intra-operative 3D-C-arms produce images of CT-like quality with low-dose radiation. Copyright © 2015 John Wiley & Sons, Ltd.

Monte Carlo and experimental internal radionuclide dosimetry in RANDO head phantom.

Monte Carlo techniques are widely employed in internal dosimetry to obtain better estimates of absorbed dose distributions from irradiation sources in medicine. Accurate 3D absorbed dosimetry would be useful for risk assessment of inducing deterministic and stochastic biological effects for both therapeutic and diagnostic radiopharmaceuticals in nuclear medicine. The goal of this study was to experimentally evaluate the use of Geant4 application for tomographic emission (GATE) Monte Carlo package for 3D internal dosimetry using the head portion of the RANDO phantom. GATE package (version 6.1) was used to create a voxel model of a human head phantom from computed tomography (CT) images. Matrix dimensions consisted of 319 × 216 × 30 voxels (0.7871 × 0.7871 × 5 mm(3)). Measurements were made using thermoluminescent dosimeters (TLD-100). One rod-shaped source with 94 MBq activity of (99m)Tc was positioned in the brain tissue of the posterior part of the human head phantom in slice number 2. The results of the simulation were compared with measured mean absorbed dose per cumulative activity (S value). Absorbed dose was also calculated for each slice of the digital model of the head phantom and dose volume histograms (DVHs) were computed to analyze the absolute and relative doses in each slice from the simulation data. The S-values calculated by GATE and TLD methods showed a significant correlation (correlation coefficient, r(2) ≥ 0.99, p < 0.05) with each other. The maximum relative percentage differences were ≤14% for most cases. DVHs demonstrated dose decrease along the direction of movement toward the lower slices of the head phantom. Based on the results obtained from GATE Monte Carlopackage it can be deduced that a complete dosimetry simulation study, from imaging to absorbed dose map calculation, is possible to execute in a single framework.

Investigation of the entrance surface dose and dose to different organs in lumbar spine imaging.

BACKGROUND: Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology. OBJECTIVE: The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views. METHODS: To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging. RESULTS: The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement. CONCLUSION: According to the results, the GR200 has greater sensitivity than the TLD-100.