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Effect of scanning parameters on dose-response of radiochromic films irradiated with photon and electron beams

Tagiling N, Ab Rashid R, Azhan SNA, Dollah N, Geso M, Rahman WN

Heliyon, 2018 Oct;4(10):e00864.
PMID: 30364574 DOI: 10.1016/j.heliyon.2018.e00864

Proper dosimetry settings are crucial in radiotherapy to ensure accurate radiation dose delivery. This work evaluated scanning parameters as affecting factors in reading the dose-response of EBT2 and EBT3 radiochromic films (RCFs) irradiated with clinical photon and electron beams. The RCFs were digitised using Epson® Expression® 10000XL flatbed scanner and image analyses of net optical density (netOD) were conducted using five scanning parameters i.e. film type, resolution, image bit depth, colour to grayscale transformation and image inversion. The results showed that increasing spatial resolution and deepening colour depth did not improve film sensitivity, while grayscale scanning caused sensitivity reduction below than that detected in the Red-channel. It is also evident that invert and colour negative film type selection negated netOD values, hence unsuitable for scanning RCFs. In conclusion, choosing appropriate scanning parameters are important to maintain preciseness and reproducibility in films dosimetry.

Matched MeSH terms: Radiation Dosage
Fulltext Demonstration of comparison between goat skin and x-ray film membranes on traditional musical instrument Kompang

Siswanto, W.A., Syiddiq, M.

Pertanika Journal of Science & Technology, 2018;26(2):585-598.
MyJurnal

This paper presents a mathematical model of the traditional musical instrument, the kompang. In this study, a mathematical model of the kompang membrane is developed to simulate the vibration of the kompang membrane in polar coordinates by implementing the Fourier-Bessel wave function. The wave equation in polar direction is applied to provide the vibration modes of the membrane with the corresponding natural frequencies of the circular membrane. The initial and boundary conditions are determined to allow the development of numerical equation based on kompang membrane attachment. The mathematical model is coded in Smath for the numerical analysis as well as the plotting tool. Two kompang membrane cases with different membrane materials i.e. goat-skin and x-ray film are tried to test the model. The Finite Element Method (FEM) programme, Mecway, shows that the natural frequencies and the corresponding mode shapes are comparable with those from the developed model.

Matched MeSH terms: Radiation
Quality control in dual head gamma-cameras: Comparison between methods and software used for image analysis

Edam AN, Fornasier MR, De Denaro M, Sulieman A, Alkhorayef M, Bradley DA

Appl Radiat Isot, 2018 Nov;141:288-291.
PMID: 30122471 DOI: 10.1016/j.apradiso.2018.07.027

Patient radiation dose and image quality are primary issues in the conduct of nuclear medicine (NM) procedures. A range of protocols are currently used in image acquisition and analysis of quality control (QC) tests, with National Electrical Manufacturers Association (NEMA) methods and protocols widely accepted in providing an accurate description, measurement and report of γ-camera performance parameters. However, no standard software is available for image analysis. Present study compares vendor QC software analysis and three types of software freely downloadable from the internet: NMQC, NM Toolkit and ImageJ-NM Toolkit software. These were used for image analysis of QC tests of γ-cameras based on NEMA protocols including non-uniformity evaluation. Ten non-uniformity QC images were obtained using a dual head γ-camera installed in Trieste General Hospital and then analyzed. Excel analysis was used as the baseline calculation for the non-uniformity test according to NEMA procedures. The results of non-uniformity analysis showed good agreement between the independent types of software and Excel calculations (the average differences were 0.3%, 2.9%, 1.3% and 1.6% for the Useful Field of View (UFOV) integral, UFOV differential, Central Field of View (CFOV) integral and CFOV differential, respectively), while significant differences were detected following analysis using the company QC software when compared with Excel analysis (the average differences were 14.6%, 20.7%, 25.7% and 31.9% for the UFOV integral, UFOV differential, CFOV integral and CFOV differential, respectively). Compared to use of Excel calculations use of NMQC software was found to be in close accord. Variation in results obtained using the three types of software and γ-camera QC software was due to the use of different pixel sizes. It is important to conduct independent analyses tests in addition to using the vendor QC software in order to determine the differences between values.

Matched MeSH terms: Radiation Dosage
Fulltext Dose enhancement effects by different size of gold nanoparticles under irradiation of megavoltage photon beam

Wan Nordiana W Abd Rahman, Raizulnasuha Ab Rashid, Mahfuzah Muhammad, Khairunisak Abdul Razak, Norhayati Dollah, Moshi Geso

Jurnal Sains Nuklear Malaysia, 2018;30(2):23-29.
MyJurnal

Gold nanoparticles (AuNPs) have been extensively investigated as dose enhancement agent to increase the lethal dose to the tumours while minimizing dose to the normal tissue. Their intriguing properties and characteristics such as small size and shape provide favorable option in increasing radiotherapy therapeutic efficiency. In this study, the effects of AuNPs size on the dose enhancement effects irradiated under megavoltage photon beams were investigated. The study was conducted in-vitro on HeLa cells using AuNPs of 5 nm and 15 nm sizes. The cells samples were incubated with AuNPs and irradiated with photon beam of energy 6 MV and 10 MV at 100 cm SSD and 10 cm x 10 cm field size. Clonogenic assay were performed to observe the dose enhancement effects on cell survival. Dose enhancement factor (DEF) were extrapolated and evaluated from the cell survival curves. The results show that both sizes of AuNPs produce dose enhancement with the larger size AuNPs of 15 nm produce more dose enhancement compare to 5 nm AuNPs for 6 MV photon beam. Dose enhancements were observed for 10 MV photon beams but DEF for both sizes AuNPs shows no differences. In conclusion, larger size AuNPs produce higher dose enhancement compare to small size of AuNPs which conclude that nanoparticles size is important factor that need to be taken into account for AuNPs to be applied in radiotherapy.

Matched MeSH terms: Dose-Response Relationship, Radiation
Tensile properties of vulcanized field natural rubber latex by electron beam

Chai CK, Md. Soot Ahmad, Wan Manshol W. Zin

Sains Malaysiana, 2008;37.

Electron beam vulcanization of natural rubber latex has been developed as an alternative to the conventional sulphur vulcanization method. This study aimed at determining the effect of electron beam dose, beam current and centrifugation to the tensile properties of field natural rubber latex. Irradiation dose and beam current ranged from 50 to 300 kGy and 1 to 15 mA respectively. The determination of tensile properties were done on cast film prepared from irradiated field latex before and after centrifugation. It was found that tensile properties increased with radiation dose but decreased with beam current. Rubber films made from centrifuged irradiated field latex were softer and showed higher tensile strength.

Matched MeSH terms: Radiation Dosage
Dimensional and structural stability of gamma irradiated stacked die quad flat no leads (QFN)

Siew PF, Wan Yusmawati Wan Yusoff, Azman Jalar

Sains Malaysiana, 2014;43:827-832.

The physical properties and structural stability of the Quad Flat No-Leads (QFN) package with different gamma radiation doses have been investigated. The packages were irradiated with Co-60 gamma radiation with varying doses of 5 Gy, 50 Gy, 500 Gy, 5 kGy and 50 kGy with operating dose of 2.54 kGylh at room temperature. The infinite focus microscope (IFM) was used to measure the dimensional change and slantinglwarpage behaviour, while the 3D CT Scan X-ray machine was used to determine the occurrence of deflection on a wire in package due to exposure. It is believed that radiation effect on ceramic filler in the epoxy mold compound (EMC) plays an important role to induce the defects and resulted in swelling of the package. The slantinglwarpage behaviour is believed to be caused by the swelling behaviour of ceramic filler and further induced structural stability. The induced stress on the EMC structural after the dimensional change and slantinglwarpage failure leads to the occurrence of wire sweep. The finding suggests that defect production in swelled ceramic filler leads to the occurrence of dimensional and structure instability.

Matched MeSH terms: Radiation Injuries
Fulltext The academic consequences of problem behaviours in middle childhood and linkages between externalising and internalising difficulties

Kong K

Jurnal Psikologi Malaysia, 2017;31:84-95.

Numerous studies have documented relationships between problem behaviours and academic achievement measures. This study was initiated to address the relationship between parentreported problem behaviour symptoms (externalising and internalising) and standardised measures of academic achievement. The sample comprised of 3678 boys and 3846 girls in Ireland who were tracked over two time points. The first wave of data was collected when the children were 9 years old, followed by a second wave when they turned 13 years. An autoregressive model linking data at age 9 and age 13 was used to test the linkages between problems behaviours (externalising and internalising) and academic achievement over time, while simultaneously controlling for within-time association. Secondarily, the study also seeks to clarify the association between symptoms of externalising and internalising within the broader domain of problem behaviours itself. Results suggested that problems behaviours evident in middle childhood appeared to undermine academic competence by early adolescence. Likewise, early academic failures were associated with later problem behaviours. On the other hand, externalising and internalising difficulties showed reciprocal relationships over time. Implications of cascade effects for research and intervention are discussed

Matched MeSH terms: Radiation
Fulltext Radiology in general practice

Balasundaram R

Family Physician, 1993;5(3):35-45.

A survey of laws and regulations governing the practice of radiology by general practitioners in Malaysis and ten other selected countries wascarried out. It showedvaryingdegrees oflegal restrictions on the use of x-ray machines in the countries studied. Most regulations reflected the concern of radiation protection forpatients andstaff. Only some countries provide training for non-medical persons in the use of x-ray machines. Radiology has an important role in primary care. Undergraduate and post-graduate education should ensure competence in basic radiological practice. KEYWORDS: X-ray, general practice, regulations.

Matched MeSH terms: Radiation Protection
Reliability of panoramic-radiograph to determine the position of third-molar from inferior-alveolar-canal

Azizah Ahmad Fauzi, Mohamed Ebrahim Parker, Norval E., Phrabhakaran N

Sains Malaysiana, 2017;46:59-65.

Cone-beam-computed-tomography (CBCT) has been useful in providing insights of relevant anatomy prior to surgical
procedures, including the assessment of the proximity of impacted mandibular-third-molar to the inferior-alveolar-canal
(IAC). It is important to understand the reliability of conventional panoramic-radiograph in the assessment of this criterion
since it is more commonly used as first line radiographic approach due to its availability and lower radiation dose. This
study aimed to investigate the reliability of conventional panoramic-radiograph in the evaluation of the proximity of
impacted mandibular-third-molar root tip to the IAC by correlating the results with CBCT. A total of 65 root tips of impacted
mandibular-third-molars that had both panoramic radiographs and CBCT images were included in this retrospective study.
Two trained observers participated in all image evaluations. A prepared standard 1 cm ruler was used to measure the
proximity of the third-molar root apices to the IACs. Measurements recorded in this study were categorized into positive
(root apex above a roof of IAC), zero (root apex was superimposed on IAC) and negative (root apex below a roof of IAC).
Data analysis was carried out using student t-test. In this study, both observers recorded statistically significant differences
in the measurement between third-molars root apices and the IAC from panoramic radiographs and CBCT images. The low
reliability of panoramic radiograph to assess the vertical proximity between these two anatomical structures suggests
the importance of additional assessment with CBCT in cases where panoramic radiograph shows superimposition of the
third molar root on the roof of the canal and presence of root below the roof of the IAC.

Matched MeSH terms: Radiation Dosage
Sub kGy photon irradiation alterations in graphite

Bradley DA, Nawi SNM, Khandaker MU, Almugren KS, Sani SFA

Appl Radiat Isot, 2020 Jul;161:109168.
PMID: 32321700 DOI: 10.1016/j.apradiso.2020.109168

Present work concerns polymer pencil-lead graphite (PPLG) and the potential use of these in elucidating irradiation-driven structural alterations. The study provides detailed analysis of radiation-induced structural interaction changes and the associated luminescence that originates from the energy absorption. Thermally stimulated emission from the different occupied defect energy levels reflects the received radiation dose, different for the different diameter PPLGs. The PPLG samples have been exposed to photon irradiation, specifically x-ray doses ranging from 1 to 10 Gy, extended to 30-200 Gy through use of a60Co gamma-ray source. Trapping parameters such as order of kinetics, activation energy and frequency factor are estimated using Chen's peak-shape method for a fixed-dose of 30 Gy. X-ray diffractometry was used to characterize the crystal structure of the PPLG, the aim being to identify the degree of structural order, atomic spacing and lattice constants of the various irradiated PPLG samples. The mean atomic spacing and degree of structural order for the different diameter PPLG are found to be 0.3332 nm and 26.6° respectively. Photoluminescence spectra from PPLG arising from diode laser excitation at 532 nm consist of two adjacent peaks, 602 nm (absorption) and 1074 nm (emission), with mean energy band gap values within the range 1.113-1.133 eV.

Matched MeSH terms: Radiation Dosage
COMPARISON OF RADIATION DOSE AND IMAGE QUALITY IN HEAD CT SCANS AMONG MULTIDETECTOR CT SCANNERS

Abuzaid MM, Elshami W, Tekin HO, Sulieman A, Bradley DA

Radiat Prot Dosimetry, 2021 Nov 03;196(1-2):10-16.
PMID: 34423365 DOI: 10.1093/rpd/ncab125

The present study compares three different multidetector CT (MDCT) scanners for routine brain imaging in terms of image quality and radiation doses. The volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose (E) were calculated. Subjective image assessment was obtained based on a scale ranging from 1 (unacceptable) to 5 (optimum). All images scored 3.5 or over, with the 160-slice MDCT images being favoured. For the 4-, 16- and 160-slice MDCT scanners, the respective median values for CTDIvol were 57 mGy, 41 mGy, and 28 mGy; DLP values were 901 mGy.cm, 680 mGy.cm, and 551 mGy.cm; and effective doses were 2 mSv, 1.5 mSv, and 1 mSv, respectively. Compared to the 160-slice MDCT, the dose values for the 4- and 16-slice units were significantly greater. In practice, the CT modality used must be carefully selected to avoid elevated radiation doses and maintain image quality.

Matched MeSH terms: Radiation Dosage
Fulltext Co-visualization of DNA damage and ion traversals in live mammalian cells using a fluorescent nuclear track detector

Kodaira S, Konishi T, Kobayashi A, Maeda T, Ahmad TA, Yang G, et al.

J Radiat Res, 2015 Mar;56(2):360-5.
PMID: 25324538 DOI: 10.1093/jrr/rru091

The geometric locations of ion traversals in mammalian cells constitute important information in the study of heavy ion-induced biological effect. Single ion traversal through a cellular nucleus produces complex and massive DNA damage at a nanometer level, leading to cell inactivation, mutations and transformation. We present a novel approach that uses a fluorescent nuclear track detector (FNTD) for the simultaneous detection of the geometrical images of ion traversals and DNA damage in single cells using confocal microscopy. HT1080 or HT1080-53BP1-GFP cells were cultured on the surface of a FNTD and exposed to 5.1-MeV/n neon ions. The positions of the ion traversals were obtained as fluorescent images of a FNTD. Localized DNA damage in cells was identified as fluorescent spots of γ-H2AX or 53BP1-GFP. These track images and images of damaged DNA were obtained in a short time using a confocal laser scanning microscope. The geometrical distribution of DNA damage indicated by fluorescent γ-H2AX spots in fixed cells or fluorescent 53BP1-GFP spots in living cells was found to correlate well with the distribution of the ion traversals. This method will be useful for evaluating the number of ion hits on individual cells, not only for micro-beam but also for random-beam experiments.

Matched MeSH terms: Cell Survival/radiation effects; Radiation Dosage; Linear Energy Transfer/radiation effects
Fulltext Radiotherapy concurrently with weekly cisplatin, followed by adjuvant chemotherapy, for N2-3 nasopharyngeal cancer: a multicenter trial of the Forum for Nuclear Cooperation in Asia

Ohno T, Thinh DH, Kato S, Devi CR, Tung NT, Thephamongkhol K, et al.

J Radiat Res, 2013 May;54(3):467-73.
PMID: 23192700 DOI: 10.1093/jrr/rrs115

The purpose of this study was to evaluate the efficacy and toxicity of radiotherapy concurrently with weekly cisplatin, followed by adjuvant chemotherapy, for the treatment of N2-3 nasopharyngeal cancer (NPC) in Asian countries, especially regions of South and Southeast Asian countries where NPC is endemic. Between 2005 and 2009, 121 patients with NPC (T1-4 N2-3 M0) were registered from Vietnam, Malaysia, Indonesia, Thailand, The Philippines, China and Bangladesh. Patients were treated with 2D radiotherapy concurrently with weekly cisplatin (30 mg/m (2)), followed by adjuvant chemotherapy, consisting of cisplatin (80 mg/m(2) on Day 1) and fluorouracil (800 mg/m(2) on Days 1-5) for 3 cycles. Of the 121 patients, 56 patients (46%) required interruption of RT. The reasons for interruption of RT were acute non-hematological toxicities such as mucositis, pain and dermatitis in 35 patients, hematological toxicities in 11 patients, machine break-down in 3 patients, poor general condition in 2 patients, and others in 8 patients. Of the patients, 93% completed at least 4 cycles of weekly cisplatin during radiotherapy, and 82% completed at least 2 cycles of adjuvant chemotherapy. With a median follow-up time of 46 months for the surviving 77 patients, the 3-year locoregional control, distant metastasis-free survival and overall survival rates were 89%, 74% and 66%, respectively. No treatment-related deaths occurred. Grade 3-4 toxicities of mucositis, nausea/vomiting and leukopenia were observed in 34%, 4% and 4% of the patients, respectively. In conclusion, further improvement in survival and locoregional control is necessary, although our regimen showed acceptable toxicities.

Matched MeSH terms: Radiation Injuries/mortality*; Radiation-Sensitizing Agents/administration & dosage
Fulltext Induced electron radiation effect on the performance of inter-satellite optical wireless communication

Youssouf AS, Hasbullah NF, Saidin N, Habaebi MH, Parthiban R, Bin Mohamed Zin MR, et al.

PLoS One, 2021;16(12):e0259649.
PMID: 34972119 DOI: 10.1371/journal.pone.0259649

This paper provides the details of a study on the effects of electron radiation on the Performance of Inters-satellite Optical Wireless Communication (IsOWC). Academia and industry focus on solutions that can improve performance and reduce the cost of IsWOC systems. Spacecraft, space stations, satellites, and astronauts are exposed to an increased level of radiation when in space, so it is essential to evaluate the risks and performance effects associated with extended radiation exposures in missions and space travel in general. This investigation focuses on LEO, especially in the near-equatorial radiation environment. Radiation experiments supported with simulations have made it possible to obtain and evaluate the electron radiation impact on optoelectronics at the device level and system level performances. The electron radiation has induced a system degradation of 70%. This result demonstrates the importance of such an investigation to predict and take necessary and suitable reliable quality service for future space missions.

Matched MeSH terms: Cosmic Radiation
Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system

Saidu A, Wagiran H, Saeed MA, Alajerami YSM, Kadir ABA

Appl Radiat Isot, 2016 Dec;118:375-381.
PMID: 27894049 DOI: 10.1016/j.apradiso.2016.10.005

The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5-1000Gy is investigated. The results show that the thermal fading behaviour is improved significantly.

Matched MeSH terms: Radiation Dosimeters
Fulltext Smartphone usage and increased risk of mobile phone addiction: A concurrent study

Parasuraman S, Sam AT, Yee SWK, Chuon BLC, Ren LY

Int J Pharm Investig, 2017 Jul-Sep;7(3):125-131.
PMID: 29184824 DOI: 10.4103/jphi.JPHI_56_17

Objective: This study aimed to study the mobile phone addiction behavior and awareness on electromagnetic radiation (EMR) among a sample of Malaysian population.

Methods: This online study was conducted between December 2015 and 2016. The study instrument comprised eight segments, namely, informed consent form, demographic details, habituation, mobile phone fact and EMR details, mobile phone awareness education, psychomotor (anxious behavior) analysis, and health issues. Frequency of the data was calculated and summarized in the results.

Results: Totally, 409 respondents participated in the study. The mean age of the study participants was 22.88 (standard error = 0.24) years. Most of the study participants developed dependency with smartphone usage and had awareness (level 6) on EMR. No significant changes were found on mobile phone addiction behavior between the participants having accommodation on home and hostel.

Conclusion: The study participants were aware about mobile phone/radiation hazards and many of them were extremely dependent on smartphones. One-fourth of the study population were found having feeling of wrist and hand pain because of smartphone use which may lead to further physiological and physiological complication.

Matched MeSH terms: Electromagnetic Radiation
Fulltext Low tube voltage prospectively ECG-triggered coronary CT angiography: a systematic review of image quality and radiation dose

Tan SK, Yeong CH, Raja Aman RRA, Ng KH, Abdul Aziz YF, Chee KH, et al.

Br J Radiol, 2018 Jul;91(1088):20170874.
PMID: 29493261 DOI: 10.1259/bjr.20170874

OBJECTIVE: This study aimed (1) to perform a systematic review on scanning parameters and contrast medium (CM) reduction methods used in prospectively electrocardiography (ECG-triggered low tube voltage coronary CT angiography (CCTA), (2) to compare the achievable dose reduction and image quality and (3) to propose appropriate scanning techniques and CM administration methods.
METHODS: A systematic search was performed in PubMed, the Cochrane library, CINAHL, Web of Science, ScienceDirect and Scopus, where 20 studies were selected for analysis of scanning parameters and CM reduction methods.
RESULTS: The mean effective dose (HE) ranged from 0.31 to 2.75 mSv at 80 kVp, 0.69 to 6.29 mSv at 100 kVp and 1.53 to 10.7 mSv at 120 kVp. Radiation dose reductions of 38 to 83% at 80 kVp and 3 to 80% at 100 kVp could be achieved with preserved image quality. Similar vessel contrast enhancement to 120 kVp could be obtained by applying iodine delivery rate (IDR) of 1.35 to 1.45 g s-1 with total iodine dose (TID) of between 10.9 and 16.2 g at 80 kVp and IDR of 1.08 to 1.70 g s-1 with TID of between 18.9 and 20.9 g at 100 kVp.
CONCLUSION: This systematic review found that radiation doses could be reduced to a rate of 38 to 83% at 80 kVp, and 3 to 80% at 100 kVp without compromising the image quality. Advances in knowledge: The suggested appropriate scanning parameters and CM reduction methods can be used to help users in achieving diagnostic image quality with reduced radiation dose.

Matched MeSH terms: Radiation Dosage
Genetic and phenotype recovery of Ananas comosus var. MD2 in response to ionizing radiation

Ma S, Mohd Raffi AN, Rosli MA, Mohd Zain NA, Ibrahim MH, Karsani SA, et al.

Sci Rep, 2023 Jan 05;13(1):182.
PMID: 36604574 DOI: 10.1038/s41598-022-26745-3

Due to their sessile nature, plants are exposed to various environmental stressors such as exposure to high levels of harmful ultraviolet (UV), ionizing, and non-ionizing radiations. This exposure may result in various damages, ranging from DNA and chromosomal aberrations to phenotypic abnormalities. As an adaptation, plants have evolved efficient DNA repair mechanisms to detect and repair any damage caused by exposure to these harmful stressors to ensure their survival. In this study, the effects of gamma radiation (as a source of ionizing radiation) on clonal Ananas comosus var. MD2 was evaluated. The morphology and physiology of the clonal plantlets before and after exposure to gamma radiation were monitored at specific time intervals. The degree of genetic variation between the samples pre- and post-irradiation was also analyzed by using inter-simple sequence repeat (ISSR) markers. The resulting data revealed that the heights of the irradiated plantlets were significantly reduced (compared to control), but improved with the recovery period. Irradiated samples also exhibited relatively good photosynthetic efficiency that further improved as the plantlets recover. These observations were supported by the ISSR analysis, where the genetic dissimilarities between the irradiated samples and control were reduced by 0.1017, after 4 weeks of recovery. Overall, our findings suggested that the phenotype recovery of the clonal A. comosus var. MD2 plantlets was contributed by their ability to detect and repair the DNA lesions (as exemplified by the reduction in genetic dissimilarity after 4 weeks) and hence allow the plantlets to undergo phenotype reversion to normal plant stature.

Matched MeSH terms: Radiation, Ionizing
Paediatric effective radiation doses during brain computed tomography angiography procedure

Salah H, Rabbaa M, Abuljoud M, Babikir E, Alkhorayef M, Tamam N, et al.

Appl Radiat Isot, 2023 Feb;192:110610.
PMID: 36525913 DOI: 10.1016/j.apradiso.2022.110610

In comparison to adults and paediatric are more sensitive to ionizing radiation exposure. Computed tomography (CT) is now the dominant source of medical radiologic tests for patients, accounting for more than 70% of total doses to the general public. Paediatric CT brain scans (with and without contrast) are routinely performed for a variety of clinical reasons. As a result, this parameter must be calculated in order to determine relative radiation risk. The goal of this study is to assess the radiation risk to children during CT brain diagnostic procedures. Three hundred fifty three child patients' radiation risk doses were assessed over the course of a year. The mean and ranged of the children's radiation doses were 40.6 ± 8.8 (27.8-45.8) CTDIvol (mGy) and 850 ± 230 (568.1-1126.4) DLP (mGy.cm) for the brain with contrast medium. For CT brain without contrast, the patients' doses were 40.9 ± 9.4 (14.27-64.07) CTDIvol (mGy), and 866.1 ± 289.3 (203.6-2484.9) DLP (mGy.cm). The characteristics related to the radiation dose were retrieved from the scan protocol generated by the CT system by the participating physicians after each procedure. Furthermore, optimizing the CT acquisition parameter is critical for increasing the benefit while lowering the procedure's radiogenic risk. The patients' radiation dose is comparable with the most previously published studies and international diagnostic reference levels (DRLs). Radiation dose optimization is recommended due to high sensitivity of the paediatric patients to ionizing radiation.

Matched MeSH terms: Radiation Dosage
A new upper limit for effective dose in patient administered with 18F-FDG for PET/CT whole-body imaging with diagnostic CT parameters

Velo P, Ismail MI, Mohandas KK, Kasilingam L

J Med Imaging Radiat Sci, 2023 Mar;54(1):43-50.
PMID: 36402716 DOI: 10.1016/j.jmir.2022.09.010

INTRODUCTION: The aim of present study is to estimate effective dose in patient undergoing 18F-FDG for whole body PET/CT imaging with diagnostic CT parameters and identify the lowest achievable total effective dose.
METHOD: A total of 2247 PET/CT patients with normal glucose level underwent 18F-FDG-whole body imaging procedures. The 18F-FDG dose of 3.7MBq per kg of patient weight administered via intravenous infusion. For CT parameters, kilovoltage of 140keV and current of 40 mAs were used for all studies. All the acquired images collected retrospectively and the effective dose was calculated for each patient using algorithm adapted from ICRP Publication 106, modified for patient weight and patient blood volume. The estimated effective doses were evaluated for patients' body weight and BMI.
RESULTS: The mean of total effective dose and standard deviation is approximately 15.08(4.52) mSv using ICRP algorithm. 56% of total patient has normal BMI and their average total effective dose is 13.6mSv. Underweight patients' effective dose can be as low as 9.6mSv even using diagnostic CT protocols.
CONCLUSION: The effective dose of PET/CT procedure in present study is one of the lowest although using diagnostic parameters for CT acquisition compared to published data worldwide. This is due to the improved sensitivity of PET and complex reconstruction technique that maintains the image quality. A significant association between body weight, BMI and effective dose is reported in present study. Therefore, it is suggested that attention must be given for underweight and ideal BMI patients while prescribing FDG activity and CT imaging parameters in order to minimize the effective dose. The effective dose reported in present study can be considered as an upper limit for effective dose in PET/CT patients with normal BMI. This upper limit can be treated as a standard limit when optimizing imaging parameters, developing algorithm for image reconstruction and prescribing activity for patients. This practice could fulfill ALARA principle that could reduce cancer risk.

Matched MeSH terms: Radiation Dosage

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