DICOM Network Roles

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DICOM Network Roles

• Successful communication - products must play
  opposite roles
• Receive images Service Class Provider (SCP)
• Send images Service Class User (SCU)

CT Image StorageSOP Class (SCU)
Network roles are defined for all DICOM Functions
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DICOM Conformance Statement

• It is Required!
• It is a Public Document
• It Conveys a Products DICOM Functionality
• It is Based on DICOM Vocabulary
• Abstract Syntaxes (SOP Classes), Transfer
  Syntaxes, SCU/SCP..
• It is Used to Compare Connectivity
• It is most Often on the Web _at_ Vendor Site
• It Does Not Address All of an Applications
  Capabilities, but should Address All of the
  Applications DICOM ones

A Major Step Towards Interoperability
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Language and dictionary
128 bit inutili (non sempre) DICM
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std DICOM
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DICOM

• (0008,0000) UL 424 4 IdentifyingGroupLength
• (0008,0020) DA 20070509 8 StudyDate
• (0008,0022) DA 20070509 8 AcquisitionDate
• (0008,0023) DA 20070509 8 ImageDate
• (0008,0030) TM 163853 6 StudyTime
• (0008,0032) TM 163933 6 AcquisitionTime
• (0008,0060) CS CT 2 Modality
• (0008,0070) LO Philips 8 Manufacturer
• (0008,0080) LO OSP S.CROCE CUNEO 18
  InstitutionName
• (0008,1040) LO RADIOLOGIA 10
  InstitutionalDepartmentName
• (0008,1090) LO Brilliance 64 14
  ManufacturerModelName
• (0010,0010) PN TEST CTDI 16 CM HEAD. 22
  PatientName
• (0010,0020) LO 11111 6 PatientID
• (0010,0030) DA 20070509 8 PatientBirthDate
• (0010,0040) CS O 2 PatientSex
• (0018,0050) DS 0.5 6 SliceThickness
• (0018,0060) DS 120 4 KVP
• (0018,0090) DS 500 4 DataCollectionDiamete
  r
• (0018,1030) LO Encefalo Ax Testa 22
  ProtocolName

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Images dimension

• Ammettendo che ogni voxel occupi 32 byte qual è
  lo spazio RAM necessario a simulare 40 cm di TAC
  di cui il seguente è parte dellheader DICOM di
  unimmagine?
• circa 170 MByte
• circa 2 Mbyte
• circa 670 Mbyte

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Geant4-DICOM interface

• Developed by L. Archambault, L. Beaulieu, V.-H.
  Tremblay (Univ. Laval and l'Hôtel-Dieu, Québec)
• Donated to Geant4 for the common profit of the
  scientific community
• under the condition that further improvements and
  developments are made publicly available to the
  community
• Released with Geant4 5.2, June 2003 in an
  extended example
• by S. Guatelli mainly
• Deeply revised in by Pedro Arce in 2007
• Small improvements by S. Chauvie

T. Aso A.Kimura Ashikaga Institute of
Technology
Geant4 examples/extended/medical/DICOM
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From phantom to MC
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cont

• 
               Density
  Range                   Materials             
  -------------------------------------------------
  --                  g/cm3                       
       -                    ----------------------
  -----------------------------            
  0.100 , 0.351                  Lungs (inhale)
               0.351 , 0.800                 
  Lungs (exhale)              0.919 , 0.979
                   Adipose                    
  0.979 , 1.004                  Breast        
               1.004 , 1.043                 
  Phantom                     1.043 , 1.109
                   Liver                      
  1.109 , 1.113                  Muscle        
               1.113 , 1.400                 
  Trabecular Bone             1.496 , 1.654
                   Dense Bone               
  

ICRU 46
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and ends.
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The structure
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From DICOM image to Geant4 geometry

• Reading image information
• Transformation of pixel data into densities
• Association of densities to a list of
  corresponding materials
• Defining the voxels
• Geant4 parameterised volumes
• parameterisation function material

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Start reading DICOM files
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Tranlsate TAGS with DICT
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Read the header and create the tag
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Implicit Endian Explicit VR, special cases
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Implicit Endian Explicit VR, other cases
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Implicit Endian Implicit VR
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Create .g4dcm
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Data.dat
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CT2Density.dat
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Write density
Splitting materials in density intervals In the
class DicomDetectorConstruction, it is defined a
density interval G4double densityDiff 0.1
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Navigation.

• The 1D optimisation . It will be very slow
  because each time a track exits a voxel it has to
  loop to all other voxels to know which one it may
  enter
• The 3D optimisation with G4SmartVoxel a 3D grid
  is built, so that the location of voxels is fast,
  but it requires a lot of memory
• Using G4NestedParameterisation. The search is
  done hierarchically in X, Y and Z. It is fast and
  does not require big memory
• Using G4PhantomParameterisation/G4RegularNavigati
  on an special algorithm to navigate in regular
  voxelised geometries (see GEANT4 doc). This is
  the fastest way without any extra memory
  requirement (and it is the default in this
  example). It includes an option (default) to skip
  frontiers between voxels when they have the same
  material. When using this option at each step the
  energy is all deposited in the last voxel for
  properly distribution of the dose
  (energy/volume) the G4PSDoseDeposit_RegNav
  scorer can be used

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MC Dose calculation in Radiotherapy
How accurate is the dose calculation ?
Description of patients
Energy deposition
Physics
Geometry
Validation studies
DICOM
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Grazie per lattenzione!