Ali Mohammed Ali
@alzahraa.edu.iq
Al-Zahraa University for Women
Scopus Publications
Scopus Publications
Andrew Lyons, Ali Mohammed Ali, Andrew England, Niamh Moore, Rena Young, Brid Leamy, Winnie Tam, Paul Bezzina, Napapong Pongnapang, and Mark F. McEntee
Elsevier BV
A. Mohammed Ali and S. Al-Murshedi
Elsevier BV
J. Saint, A. England, A. Mohammed Ali, and L. Bonnett
Elsevier BV
Sadeq Al-Murshedi, Firas Abedi, Ali Mohammed Ali, Rasha Alali, and Ihab Mahdi Almaameri
IEEE
In medical imaging, differences in patient size can cause some difficulties, particularly when it comes to choosing the optimal imaging protocol and this can influence image quality and radiation dose given to the patient. The purpose of this study is to investigate the influence of patient thickness on radiation dose received when undertaking abdomen x-ray examination. An adult anthropomorphic abdomen phantom was used for simulating the abdomen area of a real patient. In addition, three different layers of fat added above the phantom were utilised for simulating the different patient sizes. The phantom was imaged using different acquisition parameters and the radiation dose values were recorded. Radiation dose values increased with increasing phantom size and decreased with higher kVp values for all the different phantom sizes.
Ali Mohammed Ali, Sadeq Al-Murshedi, Batool Luay Aziz, Firas Abedi, and Ali S. Abosinnee
IEEE
The advanced digital imaging systems are producing much less noise associated radiographs. Physical image quality are becoming recognizable in replacing visual human evaluating of image quality. When radiation does shows strong correlation with image quality, one can directly control image quality using dose. Thus, this study aim to explore relationship between physical image quality (taken from real patient with lung infection) and radiation quantity (or doses) and to investigate possible reduction in radiation doses. The study used public data source of plain radiographs, that contains around 160,000 x-ray images. Then filtered them according the study aim and practicality to be used in measuring signal to noise ratio (SNR) and contrast to noise ratio (CNR). Strong relation between radiation dose and SNR was found, while CNR showed weak relationship with radiation dose. Very low SNR value was found to be suitable to produce visible image quality. The study concluded the possibility of utilizing physical image quality with possibility in reducing dose to the patients.
Ali Mohammed Ali, Peter Hogg, and Andrew England
Elsevier BV
OBJECTIVE
To investigate the optimum pelvis X-ray acquisition factors for a 10-year-old child. Secondly, to evaluate the impact of each acquisition factor on image quality (IQ) and radiation dose.
METHOD
Images were acquired using a pelvis phantom and a range of acquisition parameters; e.g. tube potential, additional filtration and source-to-image distance (SID). Automatic exposure control (AEC) was used with two orientations (head towards/away from two outer chambers) and three different chamber selections. Visual IQ was evaluated using relative and absolute-VGA methods. Radiation doses were measured by placing a dosimeter on the anterior surface of the phantom. Regression analysis was used to determine optimum parameters.
RESULTS
The optimised technique (178.8 µGy), with diagnostic IQ, was with 89kVp, 130 cm SID and with 1 mm Al + 0.1 mm Cu filtration. This technique was with the head towards the two outer AEC chambers. Regression analysis showed that SID had the lowest impact on IQ (β = 0.002 95% CI -0.001 to 0.005) and dose (β = -0.96 95% CI -0.40 to -1.53). The impact of filtration on dose (β = -76.24 95% CI -86.76 to -85.72) was higher than tube potential (β = -13.44 95% CI -14.34 to -12.53). The following impact ratios were higher on IQ than radiation dose: filtration/kVp; 11.28 times, filtration/SID; 7.01 times and kVp/SID; 0.62 times.
CONCLUSION
Optimised parameters were identified as 89 kVp, 130 cm SID and with 1 mm Al + 0.1 mm Cu additional filtration. Regression analysis demonstrated that filtration and tube potential had the greatest effect on radiation dose and IQ, respectively.
Ali Mohammed Ali, Peter Hogg, Mohamed Abuzaid, and Andrew England
Elsevier BV
PURPOSE
Within paediatric pelvis imaging there is a lack of systematic dose optimisation studies which consider age and size variations. This paper presents data from dose optimisation studies using digital radiography and pelvis phantoms representing 1 and 5-year-old children.
MATERIAL AND METHOD
Dose optimisation included assessments of image quality and radiation dose. Systematic variations using a factorial design for acquisition factors (kVp, mAs, source-detector distance [SDD] and filtration) were undertaken to acquire AP pelvis X-ray images. Perceptual image quality was assessed using a relative and absolute visual grading assessment (VGA) method. Radiation doses were measured by placing a dosimeter at the radiographic centring point on the surface of each phantom. Statistical analyses for determining the optimised parameters included main effects analysis.
RESULTS
Optimised techniques, with diagnostically acceptable image quality, for each paediatric age were: 1-year-old; 65 kVp, 2 mAs and 115 cm SDD, while, 5-year-old; 62 kVp, 8 mAs and 130 cm SDD both included 1 mm Al +0.1 mm Cu additional filtration. The main effect analysis identified situations in which image quality and radiation dose increased or decreased, except for kVp which showed peak image quality when exposure factors were increased. A set of minimum mAs values for producing diagnostic image quality were identified. Increasing SDD, unlike the other exposure factors, showed no trends for producing non-diagnostic images.
CONCLUSION
The factorial design provided an opportunity to identify suitable acquisition factors. This study provided a method for investigating the combined effect of multiple acquisition parameters on image quality and radiation dose for children.
Ali Mohammed Ali, Peter Hogg, Safora Johansen, and Andrew England
Elsevier BV
PURPOSE
Imaging phantoms can be cost prohibitive, therefore a need exists to produce low cost alternatives which are fit for purpose. This paper describes the development and validation of a low cost paediatric pelvis phantom based on the anatomy of a 5-year-old child.
METHODS
Tissue equivalent materials representing paediatric bone (Plaster of Paris; PoP) and soft tissue (Poly methyl methacrylate; PMMA) were used. PMMA was machined to match the bony anatomy identified from a CT scan of a 5-year-old child and cavities were created for infusing the PoP. Phantom validation comprised physical and visual measures. Physical included CT density comparison between a CT scan of a 5-year old child and the phantom and Signal to Noise Ratio (SNR) comparative analysis of anteroposterior phantom X-ray images against a commercial anthropomorphic phantom. Visual analysis using a psychometric image quality scale (face validity).
RESULTS
CT density, the percentage difference between cortical bone, soft tissue and their equivalent tissue substitutes were -4.7 to -4.1% and -23.4%, respectively. For SNR, (mAs response) there was a strong positive correlation between the two phantoms (r > 0.95 for all kVps). For kVp response, there was a strong positive correlation between 1 and 8 mAs (r = 0.85), this then decreased as mAs increased (r = -0.21 at 20 mAs). Psychometric scale results produced a Cronbach's Alpha of almost 0.8.
CONCLUSIONS
Physical and visual measures suggest our low-cost phantom has suitable anatomical characteristics for X-ray imaging. Our phantom could have utility in dose and image quality optimisation studies.