Digital Imaging started in the 1972 with Digital subtraction angiography Clinical digital imaging was employed from the 1980 ~ 37 years ago Amount of

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2 Digital Imaging started in the 1972 with Digital subtraction angiography Clinical digital imaging was employed from the 1980 ~ 37 years ago Amount of radiation to the population due to Medical Imaging has increased sixfold from 1980~2006

3 Number of diagnostic and fluoroscopic studies has sky rocked from 25millions in 1950 to 293 million in 2006 The benefit from medical radiation have remain clear for more than 100 year despite the risk Radiographers play a critical role in ensuring patient radiation safety during Medical Imaging procedures

4 Time Saving Wider Exposure Latitude Ability to incorporate images into already existing PACS, RIS, HIS Post Processing Capabilities Lower Radiation Dose compared to Film Screen systems.

5 Dose Creep: This refer to the tendency to use or give more radiation than necessary

6 Dose. ALARA principle still holds Radiation exposure used in conventional system is based largely on certain conditions Specific Screen-Film system Type of screen Type of Film Condition used to processed the film State of Chemicals

7 In digital Imaging, image acquisition, Postprocessing and display are all separated into unique stages. Due to these factors, the tendency for an image to be OVER EXPOSED or UNDEREXPOSED is high. Adjustment to compensate this over/under exposure are mostly done in the display process.

8 Best Practice The Best practice is to select the appropriate exposure techniques factors for the patient size and condition based on planned exposure system designed with the radiologist to determine adequate image quality Do we do this???

9 Image Contrast Image contrast in Digital Imaging depends on two parameters Subject Contrast Display Contrast

10 Subject Contrast depends on various tissue composition Tissue density eg Bone and Air Body thickness KVp Absorption of radiation by tissue Subject Contrast cannot be controlled or adjusted by POSTPROCESSING

11 Display Contrast.. This is dependent on Post processing software-smart computers The monitor windowing The screen resolution eg. DICOM Screen(Barco Screens- High Resolution Screens)

12 Auto adjustment of an image contrast through powerful post processing software can even ensure that an image is of diagnostic quality even if its over exposed. In Digital Imaging excess exposure doesn't affect image quality except in extreme level of exposure

13 Due to this radiographers might be inclined to adjust exposure techniques to slightly increase the amount of radiation which subsequently.. increase patient dose ~DOSE CREEP Decrease image noise Least resistance and queries from Radiologist Avoid Repeats

14 The ability to adjust the image contrast of a digital image does affect the radiographer s attention to the primary principle of radiation protection optimal image quality with minimal patient exposure Best Practice.. As expert on exposure in the radiology team,radiographers should be proactive in remaining up-to-date on the basics of radiation protection and new technologies.

15 Procedure Validity.. 12% of request from doctors are unnecessary therefore. Radiographers: Should be the last medical profession to potentially screen for appropriateness before a radiological exam Needs to be a patient advocate and protect them against unnecessary exposure

16 should consult radiologist or referring doctors request for additional information that can further indicate the correct procedure to be performed when there is a suspicion of an inappropriate exam order. tracking of previous examination to prevent duplication of procedures eg RIS, HIS, PACS

17 Best Practices it is best practice in digital radiography for the radiographer to carefully review the examination ordered to prevent potential duplication and to ensure appropriateness as related to the patient s history.

18 Departmental Protocols.. Required for department accreditation It should be made accessible to practicing radiographers Done with consultation with radiologist Eg Exposure Chart KVp mas AEC Grid

19 Screening for Pregnancy.. Verification of pregnancy is department dependent ~ department policy Child bearing age women need to be asked of the possibility of pregnancy watch out for possible physical signs and lead-up questions Professional communication can help put Patient and RAD as ease.

20 If Pregnant. There should be a departmental policy Written document-consent form Discus with Radiologist if exam is necessary or any alternate procedure can be used to avoid exposure Best Practice The screening of patient for potential pregnancy is an essential best practice for radiation safety in digital imaging

21 Appropriate and consistent use of exposure technique chart and adequate kvp and AEC is essential to procedure diagnostic image while minimize patient radiation exposure kvp. Controls the energy of radiation reacting with the image receptor. kvp should be used in the same way as in film-screen system

22 High KVp and low mas is favored by most radiographers for Adult imaging 15% increase in average KVp and a corresponding 15% reduction in mas will produce good image contrast as well as reduce patient exposure increase in KVp will increase scatter hence the need for GRIDS to improve image contrast.

23 Best Practice. A best practice in digital imaging is to use the highest kvp within the optimal range for the position and part coupled with the lowest amount of mas needed to provide an adequate exposure to the image receptor.

24 AECs. Controls exposure times hence total mas Works as same as in film screen systems. Requires frequent and systematic calibrations Modern AEC have more than 3 ionization chambers mostly 5 Needs proper positioning of anatomical part over ionizing chamber

25 Underexposure from AEC will occur if the area of anatomy is too small to cover at least one AEC cell Over Exposure on AEC.eg Metallic implant on the AEC cell Best Practice. A best practice in digital radiography is to use AEC when indicated and to use AEC that has been calibrated to the type of image receptor to provide a consistent exposure to the image receptor.

26 Anatomic Program Radiography/Exposure Chart APR- A system of programmed exposure technique setting that is organized by position and procedure and set through the control panel at the radiographers unit APR gives options for various body size(small, Medium and Large) A combination of AEC(Ionization chamber selection) Allows for Manual adjustment of parameters.

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28 Exposure Charts: It s a requirement in all radiography unit Should be accessible to all radiographers Eliminates the confusion concerning mas, kvp, SID, Grid, focal spot size etc It provide an acceptable levels of radiation that provides diagnostic image quality within the ALARA principle Drawn with typical/average patient attributes.

29 Exposure charts needs continuous monitoring and revision to ensure exposure techniques does produce diagnostic images within ALARA principle EXPOSURE CHART does not replace RADIOGRAPHERS as selection of exposures is dependent on patient condition, pathology and prevailing circumstances.

30 Best Practice: A best practice in digital radiography is to use exposure technique that are continuously improve and applicable to a wide range of patient sizes

31 Collimation/Electronic Masking Adjustment of the radiation beam to a determined area of interest. Effects: Minimize patient exposure Minimize Scatter radiation to the image receptor Improve image quality Prevent errors during postprocessing of the images

32 Masking:- Masking is an electronic software that recognizes the boarders of the exposed area on the image receptor. The area of unexposed side generally appear very bright. The mask will reduce the bright area by applying an overlay between the boarder of the exposed and unexposed areas on the receptor during post processing. Masking improve image viewing. Masking shouldn t occur within or over an anatomy of interest.

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34 Masking and cropping shouldn t be use as a REPLACEMENT for physical collimation. Physical CROPPING has a negative effect on image contrast

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36 In Digital Imaging, image receptors are more sensitive to low levels of radiations (Scatter) and the resulting digital image might demonstrate REDUCED IMAGE CONTRAST because of the excess scatter striking the receptor.

37 Collimation and Image Plate Multiple exposure can be made on an Image plate but depends on Type of Receptor used in the Image Plate Departmental protocol General Rule: Beam field should be well aligned No overlapping of exposures The need for a flexible PB covering of the unexposed/exposed side of the plate REGARDLESS of plate technology. Improve image quality

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39 Best Practices: A best practice in digital radiography is to collimate the x-ray beam to the anatomical area appropriate for the procedure. Electronic masking to improve image viewing conditions should be applied in a manner that demonstrates the actual exposure field edge to document appropriate collimation. Masking must not be applied over anatomy that was contained in the exposure field at the time of exposure.

40 Shielding A fundamental radiation safety practice in digital imaging. Lack of shielding increase the radiation exposure dose to the patient Anatomical areas close to the exposure field needs shielding It shouldn t interfere with the ROI

41 There should be a departmental protocol At a minimum, gonadal shielding should be done if ROI is within 5cm of the edge of collimation. Improper shield can interfere in image postprocessing and optimum display for ROI if the shielding material is included as part of data processing Best Practice: A best practice in digital radiography is the use of lead shielding for anatomic parts that are adjacent to the x-ray field

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43 Anatomical Markers Radiogrpahers need to use PB markers placed on the image receptor before exposure. Electronic Annotations of anatomical markers is not acceptable and not a substitue for PB marker. Failure to use PB marker has LEGAL issues There should be a departmental protocol for the site of placement of PB marker per each exams.

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45 ACR and therefore GSR re-emphasis the use of PB markers as part of the digital imaging guidelines in Radiography Best Practices A best practice in digital radiography is the consistent use of lead anatomical side markers captured on the original image during x-ray exposure.

46 Thank You