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

SU-GG-I-14: A Method to Estimate Cone-Beam CT Dose Index and Cone-Beam Dose Length Product

2010 ◽  
Vol 37 (6Part3) ◽  
pp. 3104-3104
Author(s):  
S Kim ◽  
H Song ◽  
E Samei ◽  
F Yin ◽  
T Yoshizumi
Keyword(s):  
Cone Beam Ct ◽  
Cone Beam ◽  
Dose Length Product ◽  
Ct Dose ◽  
Ct Dose Index ◽  
Beam Dose ◽  
Dose Index

scholarly journals Reducing dose of Cone-Beam CT used for patient positioning in radiooncology

2021 ◽  
Vol 7 (2) ◽  
pp. 227-230
Author(s):  
Verena Gorges ◽  
Waldemar Zylka
Keyword(s):  
Dose Reduction ◽  
Cone Beam Ct ◽  
Patient Positioning ◽  
Cone Beam ◽  
Thoracic Region ◽  
Analysis Software ◽  
Tumor Patients ◽  
Ct Dose ◽  
Full Rotation ◽  
Ct Dose Index

Abstract Cone-Beam computed tomography (CBCT) has become the most important component of modern radiotherapy for positioning tumor patients directly before treatment. In this work we investigate alternations to standard acquisition protocol, called preset, for patients with a tumor in the thoracic region. The effects of the changed acquisition parameters on the image quality are evaluated using the Catphan Phantom and the image analysis software Smári. The weighted CT dose index (CTDIW) is determined in each case and the effects of the different acquisition protocols on the patient dose are classified accordingly. Additionally, the clinical suitability of alternative presets is tested by investigating correctness of image registration using the CIRS thorax phantom. The results show that a significant dose reduction can be achieved. It can be reduced by 51% for a full rotation by adjusting the gantry speed. A more patientspecific uptake protocol for patients with laterally located tumor was created which allows a dose reduction of 54%.

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.

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.

Comparison of verification accuracy and radiation dose between megavoltage CT and kilovoltage cone-beam CT

2010 ◽  
Vol 10 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Vincent W.C. Wu ◽  
M.L. Ho ◽  
L.Y. Yuen ◽  
K.L. Li ◽  
N.F. Lai ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Error Detection ◽  
Cone Beam Ct ◽  
Longitudinal Direction ◽  
Cone Beam ◽  
Treatment Unit ◽  
Organ Doses ◽  
Common Reference ◽  
Standard Position ◽  
Verification Methods

AbstractPurpose: This study evaluated the difference in verification performance and organ doses between megavoltage computed tomography (MVCT) and kilovoltage cone-beam computed tomography (kV CBCT).Methods: Anthropomorphic phantoms of head-and-neck (H&N) and pelvic regions were scanned by the computed tomography–simulator. A common reference standard setup position for each phantom was determined. Markings of known deviations from the standard position in the lateral, longitudinal and yaw displacements were made on the phantoms. The verifications by kV CBCT and MVCT were conducted in the linear accelerator and helical tomotherapy treatment unit respectively. The phantoms were then shifted in steps according to the assigned different degree of positional deviations. The discrepancy between the detected data and the known data (δD) indicated the detection error of the verification system. Thermoluminescent dosimeters were used for dose measurements of kV CBCT and MVCT.Results: δD of the lateral translations and yaw rotation in kV CBCT of the H&N region were lower than MVCT. There were no differences in the error detection along longitudinal direction between the two verification methods. For H&N, the mean doses of the various organs were significantly lower in kV CBCT except the skin. For the pelvis, MVCT delivered significantly higher mean dose to the prostate and femoral heads.

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 Can Patient’s Body Weight Represent Body Diameter for Pediatric Size-Specific Dose Estimate in Thoracic and Abdominal Computed Tomography?

2019 ◽  
Vol 9 ◽  
pp. 24 ◽  
Author(s):  
Supika Kritsaneepaiboon ◽  
Suwadee Eng-chuan ◽  
Saowapark Yoykaew
Keyword(s):  
Computed Tomography ◽  
Body Weight ◽  
Statistical Significance ◽  
Correlation Coefficients ◽  
Effective Diameter ◽  
Dose Estimate ◽  
Ct Dose ◽  
Body Diameter ◽  
Ct Dose Index ◽  
Dose Index

Objective: The objective of the study was to determine whether body weight (BW) can be substituted for body diameters to calculate size-specific dose estimate (SSDE) in the children. Materials and Methods: A total of 196 torso computed tomography (CT) studies were retrospectively reviewed. Anteroposterior diameter (DAP) and lateral diameter (Dlat) were measured, and DAP+Dlat, effective diameter, SSDE diameter and SSDEBW were calculated. Correlation coefficients among body diameters, all SSDE types and percentage changes between CT dose index volumes and SSDEs were analyzed by BW and age subgroups. Results: Overall BW was more strongly correlated with body diameter (r = 0.919–0.960, P < 0.001) than was overall age (r = 0.852–0.898, P < 0.001). The relationship between CT dose index volume and each of the SSDE types (r = 0.934–0.953, P < 0.001), between SSDEBW and all SSDE diameters (r = 0.934–0.953, P < 0.001), and among SSDE diameters (r = 0.950–0.989, P < 0.001) overall had strong correlations with statistical significance. The lowest magnitude difference was SSDEBW−SSDEeff. Conclusion: BW can be used instead of body diameter to calculate all SSDE types, with our suggested best accuracy for SSDEeff and the least variation in age < four years and BW < 20 kg. Key Messages: Size-specific dose estimate (SSDE) is a new and accurate dose-estimating parameter for the individual patient which is based on the actual size or body diameter of the patient. BW can be an important alternative for all body diameters to estimate size-specific dose or calculate SSDE in children.

scholarly journals A Diagnosis of Maxillary Sinus Fracture with Cone-Beam CT: Case Report and Literature Review

2014 ◽  
Vol 7 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Selmi Yardimci Yilmaz ◽  
Melda Misirlioglu ◽  
Mehmet Zahit Adisen
Keyword(s):  
Computed Tomography ◽  
Case Report ◽  
Maxillary Sinus ◽  
Cone Beam Ct ◽  
Maxillofacial Surgery ◽  
Maxillofacial Trauma ◽  
Cone Beam ◽  
Maxillofacial Region ◽  
Emergency Center ◽  
Frontal Wall

The purpose of this article is to present the case of maxillofacial trauma patient with maxillary sinus fracture diagnosed with cone-beam computed tomography (CBCT) and to explore the applications of this technique in evaluating the maxillofacial region. A 23-year-old male patient attempted to our clinic who had an injury at midface with complaints of swelling, numbness. The patient was examined before in emergency center but any diagnosis was made about the maxillofacial trauma. The patient re-examined clinically and radiographically. A fracture on the frontal wall of maxillary sinus is determined with the aid of CBCT. The patient consulted with the department of maxillofacial surgery and it is decided that any surgical treatment was not necessary. The emerging technique CBCT would not be the primary choice of imaging maxillofacial trauma. Nevertheless, when advantages considered this imaging procedure could be the modality of choice according to the case.

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