| 1. |
|
|
| 2. |
|
|
| 3. |
- Herrnsdorf, Lars, et al.
(författare)
-
A method to characterize the radiation output from a cone beam O-arm using a device for dose and dose profile scanning measurement
- 2013
-
Ingår i: Medical Imaging 2013: Physics of Medical Imaging. - : SPIE. - 0277-786X .- 1996-756X. - 9780819494429 ; 8668, s. 86682-86682
-
Konferensbidrag (refereegranskat)abstract
- The O-arm system is a mobile intraoperative imaging system that is comprised of fluoroscopy and cone beam CT. The configuration of the O-arm system with absence of patient table and a broad beam width (165 mm in isocenter) brings new practical and physical requirements on how to perform dose measurements. The purpose of this study was to describe a method that overcomes this and makes it possible to characterize the radiation output from the O-arm system. A holder with a clamp and a flexible ball joint that can orientate the radiation detector support and the Mover that can be adjusted to hold the dose detector in a horizontal position was used. Evaluation of the dose response for three different dose detectors of different active length (0.3, 23.1 and 100 mm) was made for three different beam qualities. Furthermore the dose profile free in air to control the possible heel effect and width of the x-ray field during rotation was measured and the dose rate waveform was analyzed. The FWHM of the dose profile was 162 mm The dose response of the three detectors is reported. The average dose response was lower for the detector with longer active length due to the influence of the dose profile shape. From dynamic measurement total exposure time, pulse width, and the number of pulses were verified. In conclusion, an external horizontal hanging holder with mover option helps to assist to make dose measurement easier and enables characterize the radiation output from the O-arm system.
|
|
| 4. |
- Herrnsdorf, Lars
(författare)
-
Review of Methods to Control Patient Doses and Image Quality in Various CT Techniques
- 2012
-
Ingår i: Medical Physics in the Baltic States. - 1822-5721. ; , s. 97-98
-
Konferensbidrag (refereegranskat)abstract
- Medical X-ray imaging is the largest source of radiation exposure to the population from artificial sources. Computed tomography (CT) contributes with 50-80 % of that radiation. About 660 000 CT examinations (2005) are done in Sweden every year. A CT examination gives a mean effective dose of 5 mSv, which is about 10 times higher than for a corresponding conventional X-ray investigation. This presentation describes earlier, current and future dosimetric and image quality analysis methods, necessary to correspond to the rapidly developing CT-techniques.
|
|
| 5. |
- Thungström, Göran, et al.
(författare)
-
Measurement of the sensitive profile in a solid state silicon detector, irradiated by X-rays
- 2013
-
Ingår i: Journal of Instrumentation. - : IOP. - 1748-0221. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- A newly constructed solid state silicon dose profile detector is characterized concerning its sensitive profile. The use of the MEDIPIX2 sensor system displays an excellent method to align an image of an X-ray slit to a sample under test. The scanning from front to reverse side of the detector, show a decrease in sensitivity of 20%, which indicates a minority charge carrier lifetime of 0.18 ms and a diffusion length of 460 mu m. The influence of diced edges results in a volumetric efficiency of 59%, an active volume of 1.2 mm(2) of total 2.1 mm(2).
|
|
