- Monte Carlo simulations of different CT X-ray energy spectra within CTDI phantom and the influence of its changes on radiochromic film measurements. [Journal Article]
- PMPhys Med 2019; 62:105-110
- CONCLUSIONS: We describe method for CTDI measurements using radiochromic film dosimetry protocol corrected by the beam quality change within the phantom. Our results show differences in CTDI measurements of up to 5.7% when compared to using film calibration curves for beam quality in air.
- ESTABLISHMENT OF A LOW DOSE RATE GAMMA RAY CALIBRATION FIELD FOR ENVIRONMENTAL RADIATION MONITORING DEVICES. [Journal Article]
- RPRadiat Prot Dosimetry 2019 May 28
- For routine calibration of dosemeters used for environmental radiation monitoring, a low dose rate 137Cs gamma ray calibration field that fully satisfies the requirement of the ISO 4037 series was es…
For routine calibration of dosemeters used for environmental radiation monitoring, a low dose rate 137Cs gamma ray calibration field that fully satisfies the requirement of the ISO 4037 series was established in the Facility of Radiation Standards in Japan Atomic Energy Agency. Two different methods were employed to determine the reference air kerma rate, namely a conventional ionisation chamber and a G(E) function method used a newly developed scintillation spectrometer. To fulfil the requirement of the ISO 4037 and suppress scattering of Cs gamma ray within the room as far as possible, a suitable lead collimator was introduced to limit the irradiation area at test points and placed at the middle height in an irradiation room with a grating floor. From measured results of de-convoluted photon fluence spectrum and the variation of evaluated reference air kerma rates between 1.0 m and 3.0 m from the centre of the source, gamma ray scattering from the room structures was found to be negligible. The reference air kerma rate at distances between1.0 m and 3.0 m could be then interpolated by simply considering the inverse square law of the distance and air attenuation. The resulting Cs gamma ray calibration field could provide ambient dose equivalent rates of 0.7-7.2 μSv h-1 for use with environmental radiation monitoring devices. Finally, we attempted to calibrate a widely used NaI(Tl) scintillation survey metre, obtaining a quite satisfactory calibration factor. These results also imply that such survey metres can be employed to monitor affected areas and assess the progress of decontamination, as they can provide appropriate measurements of the ambient dose equivalent rate.
- NATIONAL DIAGNOSTIC REFERENCE LEVELS IN INTERVENTIONAL RADIOLOGY SUITES IN LEBANON: A MULTICENTER SURVEY. [Journal Article]
- RPRadiat Prot Dosimetry 2019 May 21
- Air kerma-area product (PKA), cumulative air kerma at patient entrance reference point, fluoroscopy time and number of images were retrospectively collected from 15 hospitals in Lebanon for 11282 flu…
Air kerma-area product (PKA), cumulative air kerma at patient entrance reference point, fluoroscopy time and number of images were retrospectively collected from 15 hospitals in Lebanon for 11282 fluoroscopically-guided interventional (FGI) procedures between March 2016 and November 2018. National diagnostic reference levels (NDRLs) were established based on the third quartile of the distribution of median values of exposure parameters per department for 27 types of FGI procedures. NDRLs were in line with international DRLs except for coronary angiography (CA), percutaneous coronary interventions (PCI) and transcatheter aortic valve implantation (TAVI) which require optimisation. Additionally, following the National Council on Radiation Protection and Measurements report 168, PCI, TAVI, triple chamber pacemaker implantation, endovascular aortic repair, nephrostomy, kyphoplasty and percutaneous transhepatic biliary drainage were classified as potentially high-dose procedures with >5% of the patients with PKA exceeding 300 Gycm2. The established NDRLs will promote dose optimisation and patient radiation protection.
- Radiation exposure during non-thrombotic iliac vein stenting. [Journal Article]
- VVascular 2019 May 08; :1708538119848558
- CONCLUSIONS: With the adjunctive use of intravascular ultrasound, iliac vein stenting can be safely and effectively performed with very low utilization of fluoroscopy, and therefore radiation exposure can be minimized for both patients and surgeons. Placement of >1 iliac vein stent resulted in higher cumulative air kerma and fluoroscopy time.
- Automated air kerma strength quality assurance of permanent seed implant prostate brachytherapy sources using vendor autoradiographs. [Journal Article]
- BBrachytherapy 2019 May 04
- CONCLUSIONS: This work depicts a clinically useful tool to aid in QA of preloaded brachytherapy permanent seed implant needles without compromising sterility or increasing clinical workloads. With this procedure, each individual seed's AKS can be verified automatically before a patient's scheduled implant or retroactively when auditing patient records.
- Estimation of primary radiation output for wide-beam computed tomography scanner. [Journal Article]
- JAJ Appl Clin Med Phys 2019; 20(6):152-159
- CONCLUSIONS: A method for describing the in-air primary radiation output in a wide-beam CT scanner was proposed that provides a means to characterize the scatter-to-primary ratio of the CT scanner.
- Retrospective study of patients radiation dose during cardiac catheterization procedures. [Journal Article]
- BJBr J Radiol 2019 May 14; :20181021
- CONCLUSIONS: We have analyzed patient radiation doses from six commonly used procedures in our cardiac catheterization laboratories and suggested possible initial values for benchmark from these procedures for the fluoroscopy time, KAP and air-kerma at the interventional reference point based on our current practices. Our data compare well with published values reported in the literature by investigators who have also studied patient doses and established benchmark dose levels for their facilities. Procedure-specific benchmark dose data for various groups of patients can provide the motivation for monitoring practices to promote improvements in patient radiation dose optimization in the cardiac catheterization laboratories.
- Preventing Harm From Fluoroscopically Guided Interventional Procedures With a Risk-Based Analysis Approach. [Journal Article]
- JAJ Am Coll Radiol 2019 Apr 25
- CONCLUSIONS: This work demonstrates the application of formal risk-based analysis techniques in FGI procedures. These high priority interventions may be valuable for other facilities to consider when performing potentially high-radiation dose procedures and conducting risk-benefit analyses. Formal risk analysis techniques such as the HFMEA process are recommended for other facilities to use to improve safety for their high-risk procedures.
- Incidence of Chronic Radiodermatitis after Fluoroscopically Guided Interventions: A Retrospective Study. [Journal Article]
- JVJ Vasc Interv Radiol 2019; 30(5):692-698.e13
- CONCLUSIONS: This study shows that chronic radiodermatitis may be considered a frequent side effect in an at-risk population. The lesions are commonly benign, but extensive sclerosis can occur. Patients should be better informed about the side effects and offered a skin exam periodically.
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- CONVERSION COEFFICIENTS FROM AIR KERMA TO DIRECTIONAL DOSE EQUIVALENT H'(0.07) FOR PHOTONS. [Journal Article]
- RPRadiat Prot Dosimetry 2019 Apr 24
- New conversion coefficients from air kerma free-in-air, Ka, to directional dose equivalent at 0.07mm depth, H'(0.07), are provided for monoenergetic values and for the spectra of the radiation qualit…
New conversion coefficients from air kerma free-in-air, Ka, to directional dose equivalent at 0.07mm depth, H'(0.07), are provided for monoenergetic values and for the spectra of the radiation qualities defined in ISO 4037-1. The interpolation procedure of the monoenergetic conversion coefficients from ICRU Report 57 was improved compared to former publications. The values resulting from the new interpolation procedure describe the energy dependence of the conversion coefficients more accurately and differ by up to 5% between 50keV and 100keV from former values. Due to an additional change of the extrapolation to low energies, the values for angles of radiation incidence above 60° and energies below 40keV changed by up to 50%. The influence on the spectrum weighted conversion coefficients is similar to the changes of the monoenergetic values.