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X-ray spectra and quality parameters from Monte Carlo simulation and analytical filters

Salehi Z, Ya Ali NK, Yusoff AL

Appl Radiat Isot, 2012 Nov;70(11):2586-9.
PMID: 22940409 DOI: 10.1016/j.apradiso.2011.12.007

BEAMnrc was used to derive the X-ray spectra, from which HVL and homogeneity coefficient were determined, for different kVp and filtration settings. Except for the peak at 61 keV, the spectra are in good agreement with the IPEM report 78 data for the case of filtered beams, whereas the unfiltered beams exhibit softer spectra. Although the current attenuation data deviates from the IPEM 78 data by ~±0.5%, this has negligible effects on the calculated HVL values.

Matched MeSH terms: Radiation Protection/methods
Personnel exposure during cerebral angiography

Lam ES

Med J Malaysia, 1979 Dec;34(2):171-3.
PMID: 548723
Matched MeSH terms: Radiation Protection/methods
Reliability in individual monitoring service

Mod Ali N

Radiat Prot Dosimetry, 2011 Mar;144(1-4):90-4.
PMID: 21147789 DOI: 10.1093/rpd/ncq454

As a laboratory certified to ISO 9001:2008 and accredited to ISO/IEC 17025, the Secondary Standard Dosimetry Laboratory (SSDL)-Nuclear Malaysia has incorporated an overall comprehensive system for technical and quality management in promoting a reliable individual monitoring service (IMS). Faster identification and resolution of issues regarding dosemeter preparation and issuing of reports, personnel enhancement, improved customer satisfaction and overall efficiency of laboratory activities are all results of the implementation of an effective quality system. Review of these measures and responses to observed trends provide continuous improvement of the system. By having these mechanisms, reliability of the IMS can be assured in the promotion of safe behaviour at all levels of the workforce utilising ionising radiation facilities. Upgradation of in the reporting program through a web-based e-SSDL marks a major improvement in Nuclear Malaysia's IMS reliability on the whole. The system is a vital step in providing a user friendly and effective occupational exposure evaluation program in the country. It provides a higher level of confidence in the results generated for occupational dose monitoring of the IMS, thus, enhances the status of the radiation protection framework of the country.

Matched MeSH terms: Radiation Protection/methods
Radiation exposure during travelling in Malaysia

Omar M, Hassan A, Sulaiman I

Radiat Prot Dosimetry, 2006;121(4):456-60.
PMID: 16702237

Absorbed dose rates in vehicles during travelling by different modes of transport in Malaysia were measured. Radiation levels measured on roads in Peninsular Malaysia were within a broad range, i.e. between 36 and 1560 nGy h(-1). The highest reading, recorded while travelling near monazite and zircon mineral dumps, was 13 times the mean environmental radiation level of Malaysia. It is evident that radioactive material dumps on the roadsides can influence the radiation level on the road. The absorbed dose rates measured while travelling on an ordinary train were between 60 and 350 nGy h(-1). The highest reading was measured when the train passed a tunnel built through a granite rock hill. The measurement during sea travelling by ferries gave the lowest radiation level owing to merely cosmic radiation at the sea level.

Matched MeSH terms: Radiation Protection/methods*
ASSESSMENT ON THE INTERCHANGEABILITY OF PERSONAL EFFECTIVE DOSE ALGORITHMS IN FLUOROSCOPY-GUIDED INTERVENTIONS USING BLAND-ALTMAN ANALYSIS

Bohari A, Hashim S, Ghoshal SK, Mohd Mustafa SN

Radiat Prot Dosimetry, 2019 Dec 31;186(4):462-468.
PMID: 31329977 DOI: 10.1093/rpd/ncz051

Long exposure to radiation from fluoroscopy-guided interventions (FGIs) can be detrimental to both patients and radiologists. The effective doses received by the interventional radiology staff after performing 230 FGIs in a year were assessed by using double dosimetry and five various algorithms. The Shapiro-Wilk test revealed normally-distributed data (p < 0.01), while the significant correlation coefficients between the effective doses ranged between 0.88 and 1.00. As for the Bland-Altman analysis, both Niklason and Boetticher algorithms strongly supported the absence of statistical significance between the estimated effective doses. This portrays that the occupational doses received by the interventional radiology staff during FGIs fall within the acceptable limit regardless of the varied algorithms applied. In short, the Niklason and Boetticher algorithms appeared to be the more interchangeable ones for effective evaluation of doses. This is in view of their strong mutual correlations and excellent agreement.

Matched MeSH terms: Radiation Protection/methods*
Influence of exposure and geometric parameters on absorbed doses associated with common neuro-interventional procedures

Safari MJ, Wong JHD, Jong WL, Thorpe N, Cutajar D, Rosenfeld A, et al.

Phys Med, 2017 Mar;35:66-72.
PMID: 28256398 DOI: 10.1016/j.ejmp.2017.02.002

PURPOSE: The purpose of this study was to investigate the effects of routine exposure parameters on patient's dose during neuro-interventional radiology procedures.
METHODS: We scrutinized the routine radiological exposure parameters during 58 clinical neuro-interventional procedures such as, exposure direction, magnification, frame rate, and distance between image receptor to patient's body and evaluate their effects on patient's dose using an anthropomorphic phantom. Radiation dose received by the occipital region, ears and eyes of the phantom were measured using MOSkin detectors.
RESULTS: DSA imaging technique is a major contributor to patient's dose (80.9%) even though they are used sparingly (5.3% of total frame number). The occipital region of the brain received high dose largely from the frontal tube constantly placed under couch (73.7% of the total KAP). When rotating the frontal tube away from under the couch, the radiation dose to the occipital reduced by 40%. The use of magnification modes could increase radiation dose by 94%. Changing the image receptor to the phantom surface distance from 10 to 40cm doubled the radiation dose received by the patient's skin at the occipital region.
CONCLUSION: Our findings provided important insights into the contribution of selected fluoroscopic exposure parameters and their impact on patient's dose during neuro-interventional radiology procedures. This study showed that the DSA imaging technique contributed to the highest patient's dose and judicial use of exposure parameters might assist interventional radiologists in effective skin and eye lens dose reduction for patients undergoing neuro-interventional procedures.

Matched MeSH terms: Radiation Protection/methods
Fulltext Development of custom lead shield and strainer for targeted irradiation for mice in the gamma cell chamber

Hasan N, Sham NFR, Karim MKA, Fuad SBSA, Hasani NAH, Omar E, et al.

Sci Rep, 2021 Jul 15;11(1):14559.
PMID: 34267293 DOI: 10.1038/s41598-021-93964-5

We presented a development of a custom lead shield and mouse strainer for targeted irradiation from the gamma-cell chamber. This study was divided into two parts i.e., to (i) fabricate the shield and strainer from a lead (Pb) and (ii) optimize the irradiation to the mice-bearing tumour model with 2 and 8 Gy absorbed doses. The lead shielding was fabricated into a cuboid shape with a canal on the top and a hole on the vertical side for the beam path. Respective deliveries doses of 28 and 75 Gy from gamma-cell were used to achieve 2 and 8 Gy absorbed doses at the tumour sites.

Matched MeSH terms: Radiation Protection/methods*
Patient Exposure during Fluoroscopy-guided Pacemaker Implantation Procedures

Alkhorayef M, Sulieman A, Babikir E, Daar E, Alnaaimi M, Alduaij M, et al.

Appl Radiat Isot, 2018 Aug;138:14-17.
PMID: 28830729 DOI: 10.1016/j.apradiso.2017.08.010

A pacemaker, which is used for heart resynchronization with electrical impulses, is used to manage many clinical conditions. Recently, the frequency of pacemaker implantation procedures has increased to more than 50% worldwide. During this procedure, patients can be exposed to excessive radiation exposure. Wide range of doses has been reported in previous studies, suggesting that optimization of this procedure has not been fulfilled yet. The current study evaluated patient radiation exposure during cardiac pacemaker procedures and quantified the patient effective dose. A total of 145 procedures were performed for five pacemaker procedures (VVI, VVIR, VVD, VVDR, and DDDR) at two hospitals. Patient doses were measured using the kerma-area product meter. Effective doses were estimated using software based on Monte Carlo simulation from the National Radiological Protection Board (NRPB, now The Health Protection Agency). The effective dose values were used to estimate cancer risk from the pacemaker procedure. Patient demographic data and exposure parameters for fluoroscopy and radiography were quantified. The mean patient doses ± SD per procedure (Gycm2) for VVI, VVIR, VVD, VVDR, and DDDR were 1.52 ± 0.13 (1.43-1.61), 3.28 ± 2.34 (0.29-8.73), 3.04 ± 1.67 (1.57-4.86), 6.04 ± 2.326 3.29-8.58), and 8.8 ± 3.6 (4.5-26.20), respectively. The overall patient effective dose was 1.1mSv per procedure. It is obvious that the DDDR procedure exposed patients to the highest radiation dose. Patient dose variation can be attributed to procedure type, exposure parameter settings, and fluoroscopy time. The results of this study showed that patient doses during different pacemaker procedures are lower compared to previous reported values. Patient risk from pacemaker procedure is low, compared to other cardiac interventional procedures. Patients' exposures were mainly influenced by the type of procedures and the clinical indication.

Matched MeSH terms: Radiation Protection/methods