LDRD "Siberia"
Introduction
Purpose
Description
Parameters
Software
Features
Production
Publications
References
How to contact
Links

Яндекс цитирования
1996. Big Gold medal of"Siberian Fair"
1997. Diploma of"RusExpo"
1998. Big Gold medal of"Siberian Fair"
Introduction:

In 1982-84, in Budker Institute of Nuclear Physics a Low dose Digital Radiographic Device (LDRD) was designed. Up to now to registration of x-ray quanta a multiwire proportional chamber was used. Presently, we suggest essentially improved installation with new detector - Multichannel Ionisation Chamber (MIC). Application of the new detector allows to improve the spatial resolution in 1,5 times, save contrast sensitivity and patient irradiation dose, increase image acquisition speed, expand a dynamic range, make the detector more technological in manufacturing, simple and reliable.

Purpose:

Low dose Digital Radiographic Device is intended for a wide range of radiological investigations, such as research of chest, skeletal system study, pre-birth diagnostics etc. The most effective application of this installation is for preventive inspections of a chest where operative diagnostics, convenient archiving and low patient doses are necessary.

Description:

LDRD "Siberia - N" represents system of scanning type in which the image is formed with the help of the one-coordinate detector moving along researched object. Installation consists of a x-ray tube with a high-voltage generator, mechanical scanning system, the detector of x-ray radiation with electronics and a control system. Depends on operation mode, maximal image acquisition time varies from 5 sec to 10 sec (in fast mode 2.5-5 sec). To detect X-ray radiation the Multichannel Ionisation Chamber is used. During the exposure, X-ray tube, slit collimator and detector are moved simultaneously in vertical direction (for vertical scanning system). The slit collimator forms a thin fan-like beam. The detector measures distribution of radiation intensity in the horizontal direction. It is possible to imagine the detector as 1024 independent channels with a pitch of 0.4 mm. There are other high-resolution detector modifications with 1536 and 2048 channels and a pitch of 0.26 and 0.2 mm correspondingly. In vertical direction the detector moves with a step 0.175-0.35mm and forms in this way a square channel in the middle of a patient body. Line acqusition time is variable and equals to 2.5(5) or 5(10) ms in the different imaging modes. The draft image representing a matrix, is collected in the detectors memory during of the scanning. After exposure, the image data are coped to computer memory. The final image is appeared on the screen less than 20 seconds after the beginning of an exposition.

Parameters of the installation:
  • Number of image elements 1024-2048(max)
  • Image width 410mm
  • The vertical image size is variable. Max height 716 mm
  • Scanning range 1200mm
  • Image acquisition time 2.5, 5, 10 sec
  • Spatial resolution up to 2,0 lp/mm
  • Contrast sensitivity (at a dose in detector plane 0,2 mR) 1%
  • Dynamic range (latitude) >480
  • Effective patient dose while chest examination 7-15 uSv
  • Throughput, images per hour 60
  • X-ray generator range 50-120kV
Software:

Control of installation is performed with help of computer. The software includes the radiologist program, the x-ray assistant program, database of a x-ray study, and the program for hardware testing. These programs allow acquire the images on installation, visualize them, put and receive the images from archive. The software operate under Windows 2000/XP. In image processing mode, the radiologist can visualize pictures on the display of computer, interactively transform them and in this way to improve diagnostic opportunities. The basic operation is: a part of a range of density of a picture is allocated for visualization by change of the top and bottom borders, and for this part all set of gradation of brightness is used. Everything, that outside of these borders, is realized as black and white. The same operation can be done with any part of a picture. Such "density magnifier" allows to find out insignificant pathological deviations of density more easy. Changing the mentioned above borders, it is possible to estimate a condition of various tissues. This opportunity causes by a wide dynamic range of installation.

With the help of programs of mathematical processing, the digital image could be transformed to the most convenient state for the visual analysis. Such programs, as underlining of contours or additional expansion of a range of the density simultaneously observably on the screen are used. The image processing software constantly is under construction and it could be delivered in earlier supplied installations. The digital kind of the image allows to get the quantitative diagnostic information. It is possible to measure distances, angles, the sizes of volumes or pathological formations. It is possible to measure relative density in each point of a picture or average relative density in any fragment of an image. The radiologist software contains also some service programs - increasing of the sizes of a picture on the screen, positive - negative inversion, simultaneous visualization of several images. It can be direct and lateral projection or the images made in different time and the images from the archive. In case of need the doctor can start a special external task of processing of the received information. An example - the program of birth modelling used in the Moscow Mother and Child Health Protection Center was developed together with experts of the center.

Demo images:
You can download some images from the archive.
The basic features of the installation:

In spite of the fact that in new installation model the numbers of channels are increased in 2,25 times the patient irradiation doses remained on former level. Measurements of effective doses of an irradiation were performed by The Russian Medical Academy of Postgraduate Education, Moscow, with RANDO PHANTOM (USA). It means that important advantage of installation LDRD in comparison with film-screen systems is kept. The patient irradiation dose is 30-100 times less in comparison with standard film-screen examinations. The wide dynamic range, the high contrast sensitivity caused by high quantum efficiency and low level, allow to radiologist to find out insignificant pathological alterations. Application of the slit diaphragm on an input of the detector practically eliminates a background from scattered radiation. It leads to higher contrast sensitivity too.


Additionally, the digital form of x-ray image opens other opportunities at inspection
  • It's operative transformation of the image to most convenient state for the visual analysis. That is achieved by change of the bottom and top border of a density range that is displayed with the help of 256-gradation brightness
  • It's creation of a computer database with archive of pictures and possibility of image transfer over computer networks. Additionally one you can make the copies on the printer in any time
  • It's automated account of individual doses of an irradiation of each patient
  • It's appearance of the image on the screen right away after exposure. It leads to operative diagnostics. Elimination of photochemical processes and the charges connected to them create a lot of advantages in comparison with traditional x-ray devices

The lack of installation is necessarily of big image acquisition time 5(10) sec. However decrease of sharpness of the image because of small moving the patient does not occur, because a line exposition time is 5 ms only and displacement of the patient for this time is insignificant. Due to big distance a tube - detector, horizontal distortions are insignificant, and vertical are absent at any length of a picture. Essential dose reduction lets to take off from consideration a question on radiation danger even at mass inspections of the population. The physicians confirm that the images produced with LDRD show better quality than the routine fluorographic images. It lets eliminate the necessarily of additional radiography inspection in case of pathology. High contrast sensitivity, wide dynamic range, opportunity of mathematical processing, convenient image visualization lets the physicians to diagnose pathology at early stage. Practically zero doses of an irradiation allow to order the control investigation. The computer archive allows easily to carry out detailed comparison of results of different inspections. The radiologist can investigate the images in any convenient time. Formation of a computer database during mass inspection allows to carry out the statistical analysis of the stored information.
The retrenchment from using of LDRD instead of standard film-screen devices is approximately 15 thousand US dollars per one year at 20 patient per day. Additionally the LDRD is in 4-5 times cheaper, than analogues with similar quality of the image.

Production:

Industrial production of installations under documentation of BINP is begun since 1997. Now they are made with 3 factories - in cities: Orel - Orel region, Lesnoj -Sverdlovsk area, Berdsk - Novosibirsk area. In total, to January 2001 about 90 installations work in Russia clinics. The factory in Orel produces also "Mobil system for radiography". The license for the right of manufacture LDRD was sold to Chinese and Korean companies.

Publications:
To open publication list press here ->
References:
To open publication list press here ->
If you have some questions about the installation please contact with us:
Prof. S.E.Baru
Budker Institute of Nuclear Physics
11, Lavrentiev Avenue
Novosibirsk, 630090
RUSSIA
Phone: +7(383)329-41-84
Fax: +7(383)330-71-63

You can contact with us via e-mail:
S.E.Baru@inp.nsk.su
Links:
Download demo software.