- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effectiveness of a novel real-time dosimeter in interventional radiology: a comparison of new and old radiation sensors
摘要： Radiation dose management is important in interventional radiology (IR) procedures, such as percutaneous coronary intervention, to prevent radiation-induced injuries. Therefore, radiation dose should be monitored in real time during IR. This study evaluated the fundamental characteristics of a novel real-time skin dosimeter (RTSD) developed at our institution. In addition, we compared the performance of our new and old radiation sensors and that of a skin dose monitor (SDM), with ion chamber reference values. We evaluated the fundamental characteristics (e.g., energy dependence, dose dependence, and angular dependence) of the RTSD developed by us in the diagnostic X-ray energy range. The performance of our RTSD was similar to that of the SDM. In particular, the new radiation sensor of our RTSD demonstrated better dose rate dependence compared to the old sensor. In addition, the new sensor had the advantage of being small in size and thus minimally affecting the X-ray images compared to the old sensor. Therefore, the developed skin dosimeter and radiation sensor may be useful in real-time measurement of patients’ exposure to and multi-channel monitoring of radiation in IR procedures. The new dosimeter system can be recommended for visualization and management of the radiation dose to which the patients’ skin is exposed.
关键词： Radiation dose,Real-time skin dosimeter,Interventional radiology,Radiation skin injuries
更新于2025-09-23 15:19:57
-
Optimization of cone beam computed tomography image quality in implant dentistry
摘要： This study was conducted to optimize the cone beam computed tomography image quality in implant dentistry using both clinical and quantitative image quality evaluation with measurement of the radiation dose. A natural bone human skull phantom and an image quality phantom were used to evaluate the images produced after changing the exposure parameters (kVp and mA). A 10 × 5 cm2 field of view was selected for average adult. Five scans were taken with varying kVp (70–90 kVp) first at fixed 4 mA. After assessment of the scans and selecting the best kVp, nine scans were taken with 2–12 mA, and the kVp was fixed at the optimal value. A clinical assessment of the implant‐related anatomical landmarks was done in random order by two blinded examiners. Quantitative image quality was assessed for noise/uniformity, artifact added value, contrast‐to‐noise ratio, spatial resolution, and geometrical distortion. A dosimetry index phantom and thimble ion chamber were used to measure the absorbed dose for each scan setting. The anatomical landmarks of the maxilla had good image quality at all kVp settings. To produce good quality images, the mandibular landmarks demanded higher exposure parameters than the maxillary landmarks. The quantitative image quality values were acceptable at all selected exposure settings. Changing the exposure parameters does not necessarily produce higher image quality outcomes but does affect the radiation dose to the patient. The image quality could be optimized for implant treatment planning at lower exposure settings and dose than the default settings.
关键词： radiation dose,image quality,clinical image evaluation,dental CBCT,implant treatment planning
更新于2025-09-23 15:19:57
-
Quantitative analysis of radiation dosage and image quality between digital breast tomosynthesis (DBT) with two-dimensional synthetic mammography and full-field digital mammography (FFDM)
摘要： Purpose: Currently in diagnostic setting for breast cancer, FFDM and DBT are performed conjunctively. However, performing two imaging modalities may increase radiation exposure by double. Two-dimensional reconstructed images created from DBT with 2DSM, has a potential to replace conventional FFDM in concerning both radiation dosage and image quality. With increasing concerns for individual radiation exposure, studies analyzing radiation dosage in breast imaging modalities are needed. This study compared radiation dosage and image quality between DBT + 2DSM versus FFDM. Methods and materials: 374 patients (mean age 52 years) who underwent both DBT and FFDM were retrospectively reviewed. Radiation dosage data were obtained by radiation dosage scoring and monitoring program Radimetrics (Bayer HealthCare, Whippany, NJ). Entrance dose and mean glandular doses in each breast were obtained for both modalities. To compare image quality of DBT + 2DSM and FFDM, a 5-point scoring system for lesion clarity was assessed. The parameters of radiation dosage (entrance dose, mean glandular dose) and image quality (lesion clarity scoring) were compared. Results: For entrance dose, DBT had lower mean dosage (14.8 mGy) compared with FFDM (21.8 mGy, p-value < 0.0001). Mean glandular doses for both breasts were lower in DBT (Left 1.74, Right 2.1) compared with FFDM (Left 2.85, Right 2.74, p-value < 0.0001). Lesion clarity score was higher in DBT with 2DSM (mean score 4.03) compared with FFDM (3.82, p-value < 0.0001). Conclusion: DBT showed lower radiation entrance dose and mean glandular doses to both breasts compared with FFDM. DBT + 2DSM had better image quality than FFDM, suggesting that DBT with 2DSM has potential as an alternative to FFDM.
关键词： Radimetrics,Full-field digital mammography,Image quality,2-Dimensional synthetic mammography,Digital breast tomosynthesis,Radiation dose
更新于2025-09-19 17:15:36
-
Radiology, Lasers, Nanoparticles and Prosthetics || 2. Nuclei and isotopes
摘要： In Chapters 5 to 12 nuclear methods in medicine are discussed either for imaging (scintigraphy, SPECT, PET) or for radiation treatment of cancerous tissues (proton and neutron irradiation, brachytherapy). It is therefore appropriate to first introduce some basic properties of nuclides and isotopes, and in particular of radioactive isotopes which are used in nuclear medicine. This chapter is not intended to replace a textbook on nuclear physics. But it provides sufficient background information for better understanding the subsequent chapters. Handling of radiation in general and application of radioactive isotopes also requires a detailed knowledge of radiation dose and radiation safety, which are topics of Chapter 4.
关键词： scintigraphy,medicine,SPECT,neutron irradiation,PET,brachytherapy,radiation safety,proton irradiation,nuclides,cancerous tissues,isotopes,radioactive isotopes,radiation dose,imaging,nuclear medicine,nuclear methods,radiation treatment
更新于2025-09-19 17:13:59
-
Chemo-treated 4T1 breast cancer cells radiation response measured by single and multiple cell ionization using infrared laser trap
摘要： We present a study that uses a laser trapping technique for measurement of radiation sensitivity of untreated and chemo-treated cancer cells. We used a human mammary tumor cell line (4T1) treated by an antitumor compound, 2-Dodecyl-6-methoxycyclohexa-2, 5-diene-1,4-dione (DMDD), which was extracted from the root of Averrhoa carambola L. The untreated control group, and both 2-hour and 24-hour treated groups of 4T1 cells were used in this study. The absorbed threshold ionization energy (TIE) and the threshold radiation dose (TRD) were determined using a high-power infrared laser (at 1064 nm) trap by single and multiple cells trapping and ionization. The results were analyzed using descriptive and t-statistics. The relation of the TIE and TRD to the mass of the individual cells were also analyzed for different hours of treatment in comparison with the control group. Both TIE and TRD decrease with increasing treatment periods. However, the TRD decreases with mass regardless of the treatment. Analyses of the TRD for single vs multiple cells ionizations within each group have also consistently showed this same behavior regardless of the treatment. The underlying factors for these observed relations are explained in terms of radiation, hyperthermia, and chemo effects.
关键词： threshold ionization energy,chemo-treated cancer cells,threshold radiation dose,4T1 breast cancer cells,laser trapping technique,DMDD,radiation sensitivity
更新于2025-09-11 14:15:04
-
Low-dose CT imaging of the acute abdomen using model-based iterative reconstruction: a prospective study
摘要： Objectives Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms. Materials and methods Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10–20% and 80–90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews. Results A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (p < 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m2 than those with BMI ≥ 25 kg/m2 (5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU, p < 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (p < 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (p < 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis. Conclusions Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.
关键词： Iterative reconstruction,Computed tomography,Acute abdominal imaging,Dose optimization,Radiation dose reduction
更新于2025-09-09 09:28:46
-
Computed Tomography Imaging of the Coronary Arteries: State of the Art Applications and Recent Patents
摘要： Computed tomography (CT) is important for the management of many medical illnesses, including coronary artery disease (CAD). However this technique is not free from disadvantages like the exposure to ionizing radiations and to iodinated contrast agents. To overcome these problems, imaging technologies are changing rapidly. New-generation computed tomography scanners (NGCCT) may bring substantial advantages over traditional CT and other currently used imaging methods. These novel tools employ dedicated protocols to shorten imaging times and reduce radiation doses without affecting accuracy. Current CT scanners can very accurately identify severe CAD requiring intervention in most patients, but NGCCT may further benefit imaging for some “difficult” patients like obese patients, patients with high or irregular heart rates, and patients who have high coronary calcium burden or previous stents or bypass grafts. In fact in these patients traditional CT studies often produce suboptimal quality images. Our review presents the current status in the technical background of coronary nuclear tomographic imaging in the areas of clinical practice, and focuses on future developments of related patent forms.
关键词： Computed tomography,coronary artery disease,contrast nephrotoxicity,radiation dose,computed tomography coronary angiography,iodinated contrast medium
更新于2025-09-09 09:28:46
-
Quantitative Analysis of <sup>18</sup> F-PF-06684511, a Novel PET Radioligand for Selective β-secretase 1 Imaging, in Non-human Primate Brain
摘要： Beta-secretase 1 (BACE1) is a key enzyme in the generation of beta-amyloid, which is accumulated in the brain of Alzheimer’s disease (AD) patients. PF-06684511 was identified as a candidate PET ligand for imaging BACE1 in the brain, and showed high specific binding in an initial assessment in a non-human primate (NHP) PET study utilizing 18F-PF-06684511. In this effort, we aimed to quantitatively evaluate the regional brain distribution of 18F-PF-06684511 in NHPs under baseline and blocking conditions as well as assess the target occupancy of BACE1 inhibitors. In addition, NHP whole body PET measurements were performed to estimate the effective radiation dose. Methods: Initial brain PET measurements were performed at baseline and after oral administration of 5 mg/kg of LY2886721, a BACE1 inhibitor, in two cynomolgus monkeys. Kinetic analysis was performed with the radiometabolite-corrected plasma input function. In addition, a wide dose range of another BACE1 inhibitor, PF-06663195, was examined to investigate the relationship between the brain target occupancy and plasma concentration of the drug. Finally, the effective radiation dose of 18F-PF-06684511 was estimated based on the whole body PET measurements in NHPs. Results: Radiolabeling was accomplished successfully with an incorporation radiochemical yield of 4-12% (decay corrected) from fluorine-18 ion. The radiochemical purity was greater than 99%. The whole brain uptake of 18F-PF-06684511 reached peak (approximately 220%SUV) at approximately 20 minutes and decreased thereafter (approximately 100%SUV at 180 minutes). Two-tissue compartment model described the time activity curves well. Pre-treatment with LY2886721 reduced the total distribution volume of 18F-PF-06684511 by 48 – 80% depending on the brain regions, confirming its in vivo specificity. BACE1 occupancy of PF-06663195, estimated using Lassen occupancy plot, showed a dose-dependent increase. The effective dose of 18F-PF-06684511 was 0.043 mSv/MBq for humans. Conclusion: 18F-PF-06684511 is the first successful PET radioligand for BACE1 brain imaging that demonstrates favorable in vivo binding and brain kinetics in NHPs. (306/350 words)
关键词： PET,brain,BACE1,occupancy,radiation dose,non-human primate
更新于2025-09-04 15:30:14
-
Absorbed doses in salivary and thyroid glands from panoramic radiography and cone beam computed tomography
摘要： Introduction: Panoramic radiography and cone beam computed tomography (CBCT) are very important in the diagnosis of oral diseases, however patients are exposed to the risk of ionizing radiation. This paper describes our study aimed at comparing absorbed doses in the salivary glands and thyroid due to panoramic radiography and CBCT and estimating radiation induced cancer risk associated with those methods. Methods: Absorbed doses of two CBCT equipment (i?CAT? Next Generation and SCANORA? 3D) and a digital panoramic device (ORTHOPANTOMOGRAPH? OP200D) were measured using thermoluminescent dosimeters loaded in an anthropomorphic phantom on sublingual, submandibular, parotid and thyroid glands. Results: Absorbed doses in the i?CAT? device ranged between 0.02 (+/?0.01) and 2.23 mGy (+/?0.03), in the SCANORA? device ranged from 0.01 (+/?0.01) to 2.96 mGy (+/?0.29) and in the ORTHOPANTOMOGRAPH? OP200D ranged between 0.04 mGy and 0.78 mGy. The radiation induced cancer risk was highlighted in the salivary glands, which received higher doses. The protocols that offer the highest risk of cancer are the high resolution protocols of CBCT equipment. Conclusion: CBCT exposes patients to higher levels of radiation than panoramic radiography, so the risks and benefits of each method should be considered. The doses in CBCT were dependent on equipment and exposure parameters, therefore adequate selection minimizes the radiation dose.
关键词： Radiation dose,Cone beam computed tomography,Thermoluminescent dosimetry,Panoramic radiograph
更新于2025-09-04 15:30:14