scholarly journals Calculation of the shielding safety of Computed Tomography scanner room by using MCNP5 code

2017 ◽  
Vol 1 (T4) ◽  
pp. 63-70
Author(s):  
Khanh Ai Tran ◽  
Thong Minh Cao ◽  
Phuong Nguyen Dang ◽  
Loan Thi Hong Truong ◽  
Nhon Van Mai
Keyword(s):  
Computed Tomography ◽  
Absorbed Dose ◽  
Ct Scanner ◽  
Ct Dose ◽  
Room Size ◽  
Medical Physicists ◽  
Simulation And Experiment ◽  
Ct Dose Index ◽  
Computed Tomography Scanner ◽  
Scanner Room

Shielding design of Computed Tomography scanner room is a vital work to ensure radiation safety for medical physicists and public. In this paper, we measured CTDI (CT Dose Index) and determined the normalization factor between Monte Carlo simulation and experiment values of absorbed dose. Then, the absorbed dose distribution inside and outside the CT scanner room were surveyed for the variation of the room size. In addition, the influence of photons scattered from the shielding material to patients while shrinking the sizes of the room is also studied in this work.

Spatial Distribution of Dose in Computed Tomography with Special Reference to Thin-Slice Techniques

1987 ◽  
Vol 28 (6) ◽  
pp. 771-777 ◽  
Author(s):  
U. Moström ◽  
C. Ytterbergh
Keyword(s):  
Computed Tomography ◽  
Spatial Distribution ◽  
Dose Distribution ◽  
Absorbed Dose ◽  
Average Dose ◽  
Ct Dose ◽  
Multiple Scan ◽  
Ct Dose Index ◽  
The Difference ◽  
Dose Index

The spatial dose distribution in a cylindrical polystyrene phantom with a diameter of 200 mm was measured for seven computed tomography (CT) scanners. The measurements were performed in the head mode and mainly for narrow slices in the range 1.5 to 4 mm. Both radial and axial dose profiles were measured and the dose distribution for multiple-scan procedures was calculated. The ratio between the surface and centre doses for a single scan varied between the extremes of 1.8 and 4.3 and was generally higher for narrow than for wide slices. With multiple nominally contiguous scans the difference in absorbed dose between surface and centre locations in the object decreased, on account of scattered radiation. The CT dose index for centre locations varied considerably between the tested scanners, with a range from 5.6 to 27.2 mGy per nominal 100 mAs. For a simulated multiple-scan procedure, comparable to a CT examination of the orbits, the multiple-scan average dose varied between 4.3 and 16.4 mGy per nominal 100 mAs.

VOLUME CT DOSE INDEX AND DOSE-LENGTH PRODUCT VALUES ACCORDING TO FACILITY SIZE IN JAPAN

2020 ◽  
Vol 188 (2) ◽  
pp. 261-269
Author(s):  
Yuta Matsunaga ◽  
Yuya Kondo ◽  
Kenichi Kobayashi ◽  
Masanao Kobayashi ◽  
Kazuyuki Minami ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Volume Computed Tomography ◽  
Ct Dose Index ◽  
Computed Tomography Dose Index ◽  
Facility Size ◽  
Dose Index

Abstract The aim of this study was to investigate differences in volume computed tomography dose index (CTDIvol) and dose-length product (DLP) values according to facility size in Japan. A questionnaire survey was sent to 3000 facilities throughout Japan. Data from each facility were collected including bed number, computed tomography (CT) scan parameters employed and the CTDIvol and/or DLP values displayed on the CT scanner during each examination. The CTDIvol and DLP for 11 adult and 6 paediatric CT examinations were surveyed. Comparison of CTDIvol and DLP values of each examination according to facility size revealed key differences in CT dose between small and large facilities. This study highlights the importance of lowering the dose of coronary artery examination with contrast agent in smaller facilities and of lowering the dose of adult and paediatric head CT without contrast agent in larger facilities. The results of this study are valid in Japan.

scholarly journals Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

2019 ◽  
Vol 25 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Daryoush Khoramian ◽  
Soroush Sistani ◽  
Peyman Hejazi
Keyword(s):  
Cervical Spine ◽  
The Other ◽  
Reference Level ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Patient Doses ◽  
Ct Dose Index ◽  
Ct Scanners ◽  
Dose Levels

Abstract Objective: The literature has approved that the use of the concept of diagnostic reference level (DRL) as a part of an optimization process could help to reduce patient doses in diagnostic radiology comprising the Computed Tomography (CT) examinations. There are four public/governmental CT centers in the province (Semnan, Iran) and, to our knowledge, after about 12 years since the launch of the first CT scanner in the province there is no dosimetry information on those CT scanners. The aim of this study was to evaluate CT dose indices with the aim of the establishment of the DRL for head, chest, cervical spine, and abdomen-pelvis examinations. Methods: Scan parameters of 381 patients were collected during two months from 4 CT scanners. The CT dose index (CTDI) was measured using a calibrated ionization chamber on two cylindrical poly methyl methacrylate (PMMA) phantoms. For each sequences, weighted CTDI (CTDIw), volumetric CTDI (CTDIv) and dose length product (DLP) were calculated. The 75th percentile was proposed as the criterion for DRL values. Results: Proposed DRL (CTDIw, CTDIv, DLP) for the head, chest, cervical spine, and abdomen-pelvis were (46.1 mGy, 46.1 mGy, 723 mGy × cm), (13.8 mGy, 12.0 mGy, 377 mGy × cm), (40.0 mGy, 40.0 mGy, 572 mGy × cm) and (14.9 mGy, 12.1 mGy, 524 mGy × cm), respectively. Conclusion: Comparison with the others results from the other countries indicates that the head, chest and abdomen-pelvis scans in our region are lower or in the range of the other studies investigated in terms of dose. In the case of cervical spine scanning it’s necessary to review and regulate scan protocols to reach acceptable dose levels.

Organ doses can be estimated from the computed tomography (CT) dose index for cone-beam CT on radiotherapy equipment

2016 ◽  
Vol 36 (2) ◽  
pp. 215-229 ◽  
Author(s):  
Colin J Martin ◽  
Abdullah Abuhaimed ◽  
Marimuthu Sankaralingam ◽  
Mohamed Metwaly ◽  
David J Gentle
Keyword(s):  
Computed Tomography ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Organ Doses ◽  
Ct Dose ◽  
Ct Dose Index ◽  
Dose Index

scholarly journals A new Monte Carlo tool for organ dose estimation in computed tomography

2020 ◽  
Vol 55 (2) ◽  
pp. 123-134
Author(s):  
C. Adrien ◽  
C. Le Loirec ◽  
S. Dreuil ◽  
J.-M. Bordy
Keyword(s):  
Computed Tomography ◽  
Monte Carlo ◽  
Organ Dose ◽  
Technical Note ◽  
Patient Specific ◽  
Organ Doses ◽  
Ct Dose ◽  
Dose Information ◽  
Ct Dose Index ◽  
Mc Simulation

The constant increase of computed tomography (CT) exams and their major contribution to the collective dose led to international concerns regarding patient dose in CT imaging. Efforts were made to manage radiation dose in CT, mostly with the use of the CT dose index (CTDI). However CTDI does not give access to organ dose information, while Monte Carlo (MC) simulation can provide it if detailed information of the patient anatomy and the source are available. In this work, the X-ray source and the geometry of the GE VCT Lightspeed 64 were modelled, based both on the manufacturer technical note and some experimental data. Simulated dose values were compared with measurements performed in homogeneous conditions with a pencil chamber and then in CIRS ATOM anthropomorphic phantom using both optically stimulated luminescence dosimeters (OSLD) for point doses and XR-QA Gafchromic® films for relative dose maps. Organ doses were ultimately estimated in the ICRP 110 numerical female phantom and compared to data reported in the literature. Comparison of measured and simulated values show that our tool can be used for a patient specific and organ dose oriented radiation protection tool in CT medical imaging.

Evaluation of the CT dose index for scans with an ECG using a 320-row multiple-detector CT scanner

2014 ◽  
Vol 167 (4) ◽  
pp. 532-541 ◽  
Author(s):  
Masanao Kobayashi ◽  
Yasuki Asada ◽  
Kosuke Matsubara ◽  
Kichiro Koshida ◽  
Shouichi Suzuki ◽  
...  
Keyword(s):  
Ct Scanner ◽  
Ct Dose ◽  
Ct Dose Index ◽  
Dose Index

scholarly journals Absorbed Dose in CT : Comparison by CT Dose Index

2002 ◽  
Vol 58 (4) ◽  
pp. 495-501 ◽  
Author(s):  
KENJI YAMAMOTO ◽  
TAKASHI ANDOU ◽  
HIROSHI AKAZAWA
Keyword(s):  
Absorbed Dose ◽  
Ct Dose ◽  
Ct Dose Index ◽  
Dose Index

Experimental Examination of Radiation Doses Of Dual- and Single-Energy Computed Tomography in Chest And Upper Abdomen in a Phantom Study

2021 ◽  
Author(s):  
Denise Bos ◽  
Britta König ◽  
Sebastian Blex ◽  
Sebastian Zensen ◽  
Marcel Opitz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pulmonary Arteries ◽  
Phantom Study ◽  
Radiation Doses ◽  
Experimental Examination ◽  
Dose Length Product ◽  
Ct Dose ◽  
Dual Source ◽  
Ct Dose Index ◽  
Upper Abdomen

Abstract The aim of this phantom study is to examine radiation doses of dual- and single-energy computed tomography (DECT and SECT) in the chest and upper abdomen for three different multi-slice CT scanners. A total of 34 CT protocols were examined with the phantom N1 LUNGMAN. Four different CT examination types of different anatomic regions were performed both in single- and dual-energy technique: chest, aorta, pulmonary arteries for suspected pulmonary embolism and liver. Radiation doses were examined for the CT dose index CTDIvol and dose-length product (DLP). Radiation doses of DECT were significantly higher than doses for SECT. In terms of CTDIvol, radiation doses were 1.1–3.2 times higher, and in terms of DLP, these were 1.1–3.8 times higher for DECT compared with SECT. The third-generation dual-source CT applied the lowest dose in 7 of 15 different examination types of different anatomic regions.

scholarly journals Impact of additional mattresses in emergency CT on the automated patient centering proposed by a 3D camera: a phantom study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joël Greffier ◽  
Julien Frandon ◽  
Hélène de Forges ◽  
Aymeric Hamard ◽  
Asmaa Belaouni ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Image Noise ◽  
Ct Scanner ◽  
Anthropomorphic Phantom ◽  
Ct Dose ◽  
Tube Current ◽  
3D Camera ◽  
Ct Dose Index ◽  
The Impact ◽  
Manual Correction

AbstractTo assess the impact of the use of additional mattresses of different thicknesses on radiation dose and image noise based on the patient centering proposed by a 3D camera for CT. An anthropomorphic phantom was placed on mattresses of different thicknesses (from 3.5 to 13.5 cm) on the table of a CT scanner. The automated patient centering proposed by a 3D camera was analysed as a function of mattress thickness and corrected for table height. For this purpose, the impact on image noise in the lung tissues in the chest area and in the soft tissues in the abdomen-pelvis area, modulated mAs (mAsmod) by the tube current modulation system (TCM) and volume CT dose index (CTDIvol) was assessed slice-by-slice along the z-axis after CT scans. With the use of a mattress, the automated centering proposed by the 3D camera resulted in placement of the phantom above the isocentre. This incorrect positioning led to a significant increase in the mAsmod along the z-axis (p < 0.05) and in the CTDIvol. Image noise was significantly higher (p < 0.05) for automated phantom centering than with manual phantom centering. Differences of image noise between acquisitions with mattresses after automatic and manual phantom centering increased with the mattress thicknesses. The use of an additional mattress placed between the patient’s back and the table-top would require correcting the vertical centering proposed by the 3D camera. This manual correction is essential to avoid increased dose delivered to the patient and higher image noise.

LOCAL STUDY OF DIAGNOSTIC REFERENCE LEVELS FOR COMPUTED TOMOGRAPHY EXAMINATIONS OF ADULT PATIENTS IN İZMIR, TURKEY

2020 ◽  
Vol 190 (4) ◽  
pp. 446-451
Author(s):  
Ayşegül Yurt ◽  
İsmail Özsoykal ◽  
Recep Kandemir ◽  
Emel Ada
Keyword(s):  
Computed Tomography ◽  
Index Volume ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Local Study ◽  
Ct Dose ◽  
International Data ◽  
Ct Dose Index ◽  
Head Neck

Abstract Purpose This study aims to develop local diagnostic reference levels (DRLs) for the most common computed tomography (CT) examinations carried out around Izmir, Turkey. Methods Five common CT examinations (head, neck, chest, abdomen–pelvis (AP), chest–abdomen–pelvis (CAP)) from four different radiology centres have been included in the study. CT dose index-volume (CTDIvol) and dose length product (DLP) values were recorded for 50 patients per exam in each centre. Third quartiles of CTDIvol and DLP values were determined as DRLs and compared with international findings. Results 51.3% of the patients were male and 48.7% were female, with a mean age of 57 (between 18 and 93). DRLs for CTDIvol were recorded as 70, 16, 15, 23 and 16 for head, neck, chest, AP and CAP examinations, respectively, while the corresponding DLPs were 1385, 604, 567, 998 and 1180 mGy.cm. Conclusion Results are mostly comparable to the latest international data, except for the head examinations, which were observed to slightly exceed the DRLs established by other countries.

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