Elsevier items and derived items © 2008 by Mosby, Inc.,1
Chapter 1Chapter 1
Introduction to Digital RadiographyIntroductio...
Elsevier items and derived items © 2008 by Mosby, Inc.,2
ObjectivesObjectives
 Define the termDefine the term digital ima...
Elsevier items and derived items © 2008 by Mosby, Inc.,3
 Compare and contrast the latent image formationCompare and cont...
Elsevier items and derived items © 2008 by Mosby, Inc.,4
Key TermsKey Terms
 Computed radiographyComputed radiography
 D...
Elsevier items and derived items © 2008 by Mosby, Inc.,5
Conventional RadiographyConventional Radiography
 Method is film...
Elsevier items and derived items © 2008 by Mosby, Inc.,6
Digital ImagingDigital Imaging
 Digital imagingDigital imaging i...
Elsevier items and derived items © 2008 by Mosby, Inc.,7
Historical DevelopmentHistorical Development
of Digital Imagingof...
Elsevier items and derived items © 2008 by Mosby, Inc.,8
 Magnetic resonance imaging (MRI) became availableMagnetic reson...
Elsevier items and derived items © 2008 by Mosby, Inc.,9
 Fluoroscopic images could also be stored on aFluoroscopic image...
Elsevier items and derived items © 2008 by Mosby, Inc.,10
Digital Radiography DevelopmentDigital Radiography Development
...
Elsevier items and derived items © 2008 by Mosby, Inc.,11
Digital Radiography DevelopmentDigital Radiography Development
...
Elsevier items and derived items © 2008 by Mosby, Inc.,12
Computed RadiographyComputed Radiography
 Uses storage phosphor...
Elsevier items and derived items © 2008 by Mosby, Inc.,13
Computed RadiographyComputed Radiography
 Storage phosphor plat...
Elsevier items and derived items © 2008 by Mosby, Inc.,14
Computed RadiographyComputed Radiography
 Method was slow to be...
Elsevier items and derived items © 2008 by Mosby, Inc.,15
Digital RadiographyDigital Radiography
 Cassetteless systemCass...
Elsevier items and derived items © 2008 by Mosby, Inc.,16
 Two types of digital radiographyTwo types of digital radiograp...
Elsevier items and derived items © 2008 by Mosby, Inc.,17
 Direct capture DRDirect capture DR
• Photoconductor absorbs x-...
Elsevier items and derived items © 2008 by Mosby, Inc.,18
 First clinical application was in 1970s in digitalFirst clinic...
Elsevier items and derived items © 2008 by Mosby, Inc.,19
 DR used CCD technology developed by the militaryDR used CCD te...
Elsevier items and derived items © 2008 by Mosby, Inc.,20
Comparison of Film to CR and DRComparison of Film to CR and DR
...
Elsevier items and derived items © 2008 by Mosby, Inc.,21
 Latent image formation is different in CR and DR.Latent image ...
Elsevier items and derived items © 2008 by Mosby, Inc.,22
Comparison of Film to CR and DRComparison of Film to CR and DR
•...
Elsevier items and derived items © 2008 by Mosby, Inc.,23
Comparison of Film to CR and DRComparison of Film to CR and DR
...
Elsevier items and derived items © 2008 by Mosby, Inc.,24
Comparison of Film to CR and DRComparison of Film to CR and DR
...
Elsevier items and derived items © 2008 by Mosby, Inc.,25
Comparison of Film to CR and DRComparison of Film to CR and DR
...
Elsevier items and derived items © 2008 by Mosby, Inc.,26
Comparison of Film to CR and DRComparison of Film to CR and DR
...
Elsevier items and derived items © 2008 by Mosby, Inc.,27
Image ProcessingImage Processing
 Conventional radiographyConve...
Elsevier items and derived items © 2008 by Mosby, Inc.,28
Exposure LatitudeExposure Latitude
or Dynamic Rangeor Dynamic Ra...
Elsevier items and derived items © 2008 by Mosby, Inc.,29
Exposure LatitudeExposure Latitude
or Dynamic Rangeor Dynamic Ra...
Elsevier items and derived items © 2008 by Mosby, Inc.,30
Scatter SensitivityScatter Sensitivity
 It is important to mini...
Elsevier items and derived items © 2008 by Mosby, Inc.,31
Picture Archival andPicture Archival and
Communication SystemsCo...
Elsevier items and derived items © 2008 by Mosby, Inc.,32
 Custom designed for each facilityCustom designed for each faci...
Elsevier items and derived items © 2008 by Mosby, Inc.,33
 Early systems did not have standardized imageEarly systems did...
Elsevier items and derived items © 2008 by Mosby, Inc.,34
 First full-scale PACSFirst full-scale PACS
• Veterans Administ...
Elsevier items and derived items © 2008 by Mosby, Inc.,35
PACS UsesPACS Uses
 Made up of different componentsMade up of d...
Elsevier items and derived items © 2008 by Mosby, Inc.,36
 Early PACS seen only in radiology and some cardiologyEarly PAC...
Elsevier items and derived items © 2008 by Mosby, Inc.,37
 Orthopedic workstations are available for theOrthopedic workst...
Upcoming SlideShare
Loading in …5
×

Chapter 1 Introduction to Digital Radiography and PACS

1,782 views
1,735 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,782
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
139
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Chapter 1 Introduction to Digital Radiography and PACS

  1. 1. Elsevier items and derived items © 2008 by Mosby, Inc.,1 Chapter 1Chapter 1 Introduction to Digital RadiographyIntroduction to Digital Radiography and PACSand PACS
  2. 2. Elsevier items and derived items © 2008 by Mosby, Inc.,2 ObjectivesObjectives  Define the termDefine the term digital imagingdigital imaging..  Explain latent image formation for conventionalExplain latent image formation for conventional radiography.radiography.  Describe the latent image formation process forDescribe the latent image formation process for computed radiography.computed radiography.
  3. 3. Elsevier items and derived items © 2008 by Mosby, Inc.,3  Compare and contrast the latent image formationCompare and contrast the latent image formation process for indirect capture digital radiography andprocess for indirect capture digital radiography and direct capture digital radiography.direct capture digital radiography.  Explain what a PACS (picture archiving andExplain what a PACS (picture archiving and communication system) is and how it is used.communication system) is and how it is used.  Define digital imaging and communications inDefine digital imaging and communications in medicine.medicine. ObjectivesObjectives
  4. 4. Elsevier items and derived items © 2008 by Mosby, Inc.,4 Key TermsKey Terms  Computed radiographyComputed radiography  DICOM (digital imaging and communications inDICOM (digital imaging and communications in medicine)medicine)  Digital imagingDigital imaging  Digital radiographyDigital radiography  Direct capture DRDirect capture DR  Indirect capture DRIndirect capture DR  PACSPACS  TeleradiologyTeleradiology
  5. 5. Elsevier items and derived items © 2008 by Mosby, Inc.,5 Conventional RadiographyConventional Radiography  Method is film-based.Method is film-based.  Method uses intensifying screens.Method uses intensifying screens.  Film is placed between two screens.Film is placed between two screens.  Screens emit light when x-rays strike them.Screens emit light when x-rays strike them.  Film is processed chemically.Film is processed chemically.  Processed film is viewed on lightbox.Processed film is viewed on lightbox.
  6. 6. Elsevier items and derived items © 2008 by Mosby, Inc.,6 Digital ImagingDigital Imaging  Digital imagingDigital imaging is a broad term.is a broad term.  Term was first used medically in 1970s in computedTerm was first used medically in 1970s in computed tomography (CT).tomography (CT).  Digital imaging is defined as any image acquisitionDigital imaging is defined as any image acquisition process that produces an electronic image that canprocess that produces an electronic image that can be viewed and manipulated on a computer.be viewed and manipulated on a computer.  In radiology, images can be sent via computerIn radiology, images can be sent via computer networks to a variety of locations.networks to a variety of locations.
  7. 7. Elsevier items and derived items © 2008 by Mosby, Inc.,7 Historical DevelopmentHistorical Development of Digital Imagingof Digital Imaging  CT coupled imaging devices and the computer.CT coupled imaging devices and the computer.  Early CT scanners required hours to produce a singleEarly CT scanners required hours to produce a single slice.slice.  Reconstruction images took several days to produce.Reconstruction images took several days to produce.  First CT scanners imaged the head only.First CT scanners imaged the head only.  First scanner was developed by Siemens.First scanner was developed by Siemens.
  8. 8. Elsevier items and derived items © 2008 by Mosby, Inc.,8  Magnetic resonance imaging (MRI) became availableMagnetic resonance imaging (MRI) became available in the early 1980s.in the early 1980s.  Lauterbur paper in 1973 sparked companies toLauterbur paper in 1973 sparked companies to research MRI.research MRI.  Many scientists and researchers were involved.Many scientists and researchers were involved.  Advancements in fluoroscopy occurred in the 1970sAdvancements in fluoroscopy occurred in the 1970s as well.as well.  Analog-to-digital converters allowed real-time imagesAnalog-to-digital converters allowed real-time images to be viewed on TV monitors.to be viewed on TV monitors. Historical DevelopmentHistorical Development of Digital Imagingof Digital Imaging
  9. 9. Elsevier items and derived items © 2008 by Mosby, Inc.,9  Fluoroscopic images could also be stored on aFluoroscopic images could also be stored on a computer.computer.  Ultrasound and nuclear medicine used screenUltrasound and nuclear medicine used screen capture to grab the image and convert it digitally.capture to grab the image and convert it digitally.  Eventually, mammography converted to digitalEventually, mammography converted to digital format.format. Historical DevelopmentHistorical Development of Digital Imagingof Digital Imaging
  10. 10. Elsevier items and derived items © 2008 by Mosby, Inc.,10 Digital Radiography DevelopmentDigital Radiography Development  Concept began with Albert Jutras in Canada in theConcept began with Albert Jutras in Canada in the 1950s.1950s.  EarlyEarly PACSPACS systems were developed by the militarysystems were developed by the military to send images between Veterans Administrationto send images between Veterans Administration hospitals in the 1980s.hospitals in the 1980s.  Development was encouraged and supported by theDevelopment was encouraged and supported by the U.S. government.U.S. government.
  11. 11. Elsevier items and derived items © 2008 by Mosby, Inc.,11 Digital Radiography DevelopmentDigital Radiography Development  Early process involved scanning radiographs into theEarly process involved scanning radiographs into the computer and sending them from computer tocomputer and sending them from computer to computer.computer.  Images were then stored in PACS.Images were then stored in PACS.  Computed andComputed and digital radiographydigital radiography followed.followed.
  12. 12. Elsevier items and derived items © 2008 by Mosby, Inc.,12 Computed RadiographyComputed Radiography  Uses storage phosphor platesUses storage phosphor plates  Uses existing equipmentUses existing equipment  Requires special cassettesRequires special cassettes  Requires a special cassetteRequires a special cassette readerreader  Uses a computer workstationUses a computer workstation and viewing station and a printerand viewing station and a printer
  13. 13. Elsevier items and derived items © 2008 by Mosby, Inc.,13 Computed RadiographyComputed Radiography  Storage phosphor plates are similar to intensifyingStorage phosphor plates are similar to intensifying screens.screens.  Imaging plate stores x-ray energy for an extended time.Imaging plate stores x-ray energy for an extended time.  Process was first introduced in the United States by FujiProcess was first introduced in the United States by Fuji Medical Systems of Japan in 1983.Medical Systems of Japan in 1983.  First system used a phosphor storage plate, a reader,First system used a phosphor storage plate, a reader, and a laser printer.and a laser printer.
  14. 14. Elsevier items and derived items © 2008 by Mosby, Inc.,14 Computed RadiographyComputed Radiography  Method was slow to be accepted by radiologists.Method was slow to be accepted by radiologists.  Installation increased in the early 1990s.Installation increased in the early 1990s.  More and more hospitals are replacing film/screenMore and more hospitals are replacing film/screen technology with digital systems.technology with digital systems.
  15. 15. Elsevier items and derived items © 2008 by Mosby, Inc.,15 Digital RadiographyDigital Radiography  Cassetteless systemCassetteless system  Uses a flat panel detector or charge-coupled deviceUses a flat panel detector or charge-coupled device (CCD) hard-wired to computer(CCD) hard-wired to computer  Requires new installation of room or retrofitRequires new installation of room or retrofit
  16. 16. Elsevier items and derived items © 2008 by Mosby, Inc.,16  Two types of digital radiographyTwo types of digital radiography  Indirect capture DRIndirect capture DR • Machine absorbs x-rays and converts them to light.Machine absorbs x-rays and converts them to light. • CCD or thin-film transistor (TFT) converts light to electricCCD or thin-film transistor (TFT) converts light to electric signals.signals. • Computer processes electric signals.Computer processes electric signals. • Images are viewed on computer monitor.Images are viewed on computer monitor. Digital RadiographyDigital Radiography
  17. 17. Elsevier items and derived items © 2008 by Mosby, Inc.,17  Direct capture DRDirect capture DR • Photoconductor absorbs x-rays.Photoconductor absorbs x-rays. • TFT collects signal.TFT collects signal. • Electrical signal is sent to computer for processing.Electrical signal is sent to computer for processing. • Image is viewed on computer screen.Image is viewed on computer screen. Digital RadiographyDigital Radiography
  18. 18. Elsevier items and derived items © 2008 by Mosby, Inc.,18  First clinical application was in 1970s in digitalFirst clinical application was in 1970s in digital subtraction.subtraction.  University of Arizona scientists applied the technique.University of Arizona scientists applied the technique.  Several companies began developing large fieldSeveral companies began developing large field detectors.detectors. Digital RadiographyDigital Radiography
  19. 19. Elsevier items and derived items © 2008 by Mosby, Inc.,19  DR used CCD technology developed by the militaryDR used CCD technology developed by the military and then used TFT arrays shortly after.and then used TFT arrays shortly after.  CCD and TFT technology developed and continuesCCD and TFT technology developed and continues to develop in parallel.to develop in parallel.  No one technology has proved to be better than theNo one technology has proved to be better than the other.other. Digital RadiographyDigital Radiography
  20. 20. Elsevier items and derived items © 2008 by Mosby, Inc.,20 Comparison of Film to CR and DRComparison of Film to CR and DR  For conventional x-ray film andFor conventional x-ray film and computedcomputed radiographyradiography (CR), a traditional x-ray room with a(CR), a traditional x-ray room with a table and wall Bucky is required.table and wall Bucky is required.  For DR, a detector replaces the Bucky apparatus inFor DR, a detector replaces the Bucky apparatus in the table and wall stand.the table and wall stand.  Conventional and CR efficiency ratings are about theConventional and CR efficiency ratings are about the same.same.  DR is much more efficient, and image is availableDR is much more efficient, and image is available immediately.immediately.
  21. 21. Elsevier items and derived items © 2008 by Mosby, Inc.,21  Latent image formation is different in CR and DR.Latent image formation is different in CR and DR.  Conventional film/screenConventional film/screen • Film is placed inside of a cassette that contains an intensifyingFilm is placed inside of a cassette that contains an intensifying screen.screen. • X-rays strike the intensifying screen, and light is produced.X-rays strike the intensifying screen, and light is produced. • The light and x-ray photons interact with the silver halide grainsThe light and x-ray photons interact with the silver halide grains in the film emulsion.in the film emulsion. Comparison of Film to CR and DRComparison of Film to CR and DR
  22. 22. Elsevier items and derived items © 2008 by Mosby, Inc.,22 Comparison of Film to CR and DRComparison of Film to CR and DR • An electron is ejected from the halide.An electron is ejected from the halide. • Ejected electron is attracted to the sensitivity speck.Ejected electron is attracted to the sensitivity speck. • Speck now has a negative charge, and silver ions will beSpeck now has a negative charge, and silver ions will be attracted to equal out the charge.attracted to equal out the charge. • Process happens many times within the emulsion to formProcess happens many times within the emulsion to form the latent image.the latent image. • After chemical processing, the sensitivity specks will beAfter chemical processing, the sensitivity specks will be processed into black metallic silver and the manifest imageprocessed into black metallic silver and the manifest image is formed.is formed.
  23. 23. Elsevier items and derived items © 2008 by Mosby, Inc.,23 Comparison of Film to CR and DRComparison of Film to CR and DR  CRCR • A storage phosphor plate isA storage phosphor plate is placed inside of CR cassette.placed inside of CR cassette. • Most storage phosphor plates areMost storage phosphor plates are made of a barium fluorohalide.made of a barium fluorohalide. • When x-rays strike theWhen x-rays strike the photosensitive phosphor, somephotosensitive phosphor, some light is given off.light is given off. • Some of the photon energy isSome of the photon energy is deposited within the phosphordeposited within the phosphor particles to create the latentparticles to create the latent image.image. • The phosphor plate is then fedThe phosphor plate is then fed through the CR reader.through the CR reader.
  24. 24. Elsevier items and derived items © 2008 by Mosby, Inc.,24 Comparison of Film to CR and DRComparison of Film to CR and DR  CR, continuedCR, continued • Focused laser light is scanned over the plate, causing theFocused laser light is scanned over the plate, causing the electrons to return to their original state, emitting light in theelectrons to return to their original state, emitting light in the process.process. • This light is picked up by a photomultiplier tube andThis light is picked up by a photomultiplier tube and converted into an electrical signal.converted into an electrical signal. • The electrical signal is then sent through an analog-to-digitalThe electrical signal is then sent through an analog-to-digital converter to produce a digital image that can then be sent toconverter to produce a digital image that can then be sent to the technologist review station.the technologist review station.
  25. 25. Elsevier items and derived items © 2008 by Mosby, Inc.,25 Comparison of Film to CR and DRComparison of Film to CR and DR  DRDR • No cassettes are required.No cassettes are required. • The image acquisition device is built into the table and/orThe image acquisition device is built into the table and/or wall stand or is enclosed in a portable device.wall stand or is enclosed in a portable device. • Two distinct image acquisition methods are indirect captureTwo distinct image acquisition methods are indirect capture and direct capture.and direct capture.
  26. 26. Elsevier items and derived items © 2008 by Mosby, Inc.,26 Comparison of Film to CR and DRComparison of Film to CR and DR  DR, continuedDR, continued • Indirect capture is similar to CR in that the x-ray energyIndirect capture is similar to CR in that the x-ray energy stimulates a scintillator, which gives off light that is detectedstimulates a scintillator, which gives off light that is detected and turned into an electrical signal.and turned into an electrical signal. • With direct capture, the x-ray energy is detected by aWith direct capture, the x-ray energy is detected by a photoconductor that converts it directly to a digital electricalphotoconductor that converts it directly to a digital electrical signal.signal.
  27. 27. Elsevier items and derived items © 2008 by Mosby, Inc.,27 Image ProcessingImage Processing  Conventional radiographyConventional radiography • Image is determined by the film itself and the chemicals.Image is determined by the film itself and the chemicals.  CR and DRCR and DR • Image processing takes place in a computer.Image processing takes place in a computer. • For CR, the computer is located near the readers.For CR, the computer is located near the readers. • For DR, the computer is located next to x-ray console, or itFor DR, the computer is located next to x-ray console, or it may be integrated within the console, and the image ismay be integrated within the console, and the image is processed before moving on to the next exposure.processed before moving on to the next exposure.
  28. 28. Elsevier items and derived items © 2008 by Mosby, Inc.,28 Exposure LatitudeExposure Latitude or Dynamic Rangeor Dynamic Range  Conventional radiographyConventional radiography • Based on the characteristic response of the film, which isBased on the characteristic response of the film, which is nonlinear.nonlinear. • Radiographic contrast is primarily controlled by kilovoltageRadiographic contrast is primarily controlled by kilovoltage peak.peak. • Optical density on film is primarily controlled by milliampere-Optical density on film is primarily controlled by milliampere- second setting.second setting.
  29. 29. Elsevier items and derived items © 2008 by Mosby, Inc.,29 Exposure LatitudeExposure Latitude or Dynamic Rangeor Dynamic Range  CR and DRCR and DR • Contain a detector that can respond in a linear manner.Contain a detector that can respond in a linear manner. • Exposure latitude is wide, allowing the single detector to beExposure latitude is wide, allowing the single detector to be sensitive to a wide range of exposures.sensitive to a wide range of exposures. • Kilovoltage peak still influences subject contrast, butKilovoltage peak still influences subject contrast, but radiographic contrast is primarily controlled by an imageradiographic contrast is primarily controlled by an image processing look-up table.processing look-up table. • Milliampere-second setting has more control over image noise,Milliampere-second setting has more control over image noise, whereas density is controlled by image-processing algorithms.whereas density is controlled by image-processing algorithms.
  30. 30. Elsevier items and derived items © 2008 by Mosby, Inc.,30 Scatter SensitivityScatter Sensitivity  It is important to minimize scattered radiation with allIt is important to minimize scattered radiation with all three acquisition systems.three acquisition systems.  CR and DR can be more sensitive to scatter thanCR and DR can be more sensitive to scatter than screen/film.screen/film.  Materials used in the many CR and DR imageMaterials used in the many CR and DR image acquisition devices are more sensitive to low-energyacquisition devices are more sensitive to low-energy photons.photons.
  31. 31. Elsevier items and derived items © 2008 by Mosby, Inc.,31 Picture Archival andPicture Archival and Communication SystemsCommunication Systems  Networked group of computers,Networked group of computers, servers, and archives to storeservers, and archives to store digital imagesdigital images  Can accept any image that is inCan accept any image that is in DICOMDICOM formatformat  Serves as the file room, readingServes as the file room, reading room, duplicator, and courierroom, duplicator, and courier  Provides image access to multipleProvides image access to multiple users at the same time, on-users at the same time, on- demand images, electronicdemand images, electronic annotations of images, andannotations of images, and specialty image processingspecialty image processing
  32. 32. Elsevier items and derived items © 2008 by Mosby, Inc.,32  Custom designed for each facilityCustom designed for each facility  Components/features can vary based on the following:Components/features can vary based on the following: • Volume of patientsVolume of patients • Number of interpretation areasNumber of interpretation areas • Viewing locationsViewing locations • FundingFunding Picture Archival andPicture Archival and Communication SystemsCommunication Systems
  33. 33. Elsevier items and derived items © 2008 by Mosby, Inc.,33  Early systems did not have standardized imageEarly systems did not have standardized image formats.formats.  Matching up systems was difficult.Matching up systems was difficult.  Vendors kept systems proprietary and did not shareVendors kept systems proprietary and did not share information.information.  DICOM standards helped change this by allowingDICOM standards helped change this by allowing communication between vendors’ products.communication between vendors’ products. Picture Archival andPicture Archival and Communication SystemsCommunication Systems
  34. 34. Elsevier items and derived items © 2008 by Mosby, Inc.,34  First full-scale PACSFirst full-scale PACS • Veterans Administration Medical Center in Baltimore usedVeterans Administration Medical Center in Baltimore used PACS in 1993.PACS in 1993. • PACS covered all modalities except mammography.PACS covered all modalities except mammography. • Shortly after, PACS was interfaced with radiologyShortly after, PACS was interfaced with radiology information systems, hospital information systems, andinformation systems, hospital information systems, and electronic medical records.electronic medical records. Picture Archival andPicture Archival and Communication SystemsCommunication Systems
  35. 35. Elsevier items and derived items © 2008 by Mosby, Inc.,35 PACS UsesPACS Uses  Made up of different componentsMade up of different components • Reading stationsReading stations • Physician review stationsPhysician review stations • Web accessWeb access • Technologist quality control stationsTechnologist quality control stations • Administrative stationsAdministrative stations • Archive systemsArchive systems • Multiple interfaces to other hospital and radiology systemsMultiple interfaces to other hospital and radiology systems
  36. 36. Elsevier items and derived items © 2008 by Mosby, Inc.,36  Early PACS seen only in radiology and some cardiologyEarly PACS seen only in radiology and some cardiology departments.departments.  PACS now can be used in multiple departments.PACS now can be used in multiple departments.  Archive space can be shared among departments.Archive space can be shared among departments.  PACS reading stations may also have image processingPACS reading stations may also have image processing capabilities.capabilities.  PACS allows radiologists to reconstruct and stitchPACS allows radiologists to reconstruct and stitch images in their offices.images in their offices. PACS UsesPACS Uses
  37. 37. Elsevier items and derived items © 2008 by Mosby, Inc.,37  Orthopedic workstations are available for theOrthopedic workstations are available for the following:following: • Surgeons can plan joint replacement surgery.Surgeons can plan joint replacement surgery. • Specialized software allows matching of best replacementSpecialized software allows matching of best replacement for patient with patient anatomy.for patient with patient anatomy. • System saves time and provides better fit.System saves time and provides better fit. PACS UsesPACS Uses

×