Corso per l’utilizzo del codice GEANT4 in campo medico
Catania, 12-14 Ottobre 2009
Barbara Caccia
Stéphane Chauvie
Istituto Superiore di Sanità, RomaSanta Croce e Carle Hospital, Cuneo
CT data: Monte Carlo and DICOM standard
G4Material: compound G4Material: compound G4Material: compound G4Material: compound
Compound: composition by fraction of mass
a = 14.01*g/mole;
G4Element* elN =
new G4Element(name="Nitrogen",symbol="N",z= 7.,a);
a = 16.00*g/mole;
G4Element* elO =
new G4Element(name="Oxygen",symbol="O",z= 8.,a);
density = 1.290*mg/cm3;
G4Material* Air =
new G4Material(name="Air",density,ncomponents=2);
Air->AddElement(elN, 70.0*perCent);
Air->AddElement(elO, 30.0*perCent);
ExampleExample: : gasgasExampleExample: : gasgas
It may be necessary to specify temperature and pressure
– (dE/dx computation affected)
G4double density = 27.*mg/cm3; G4double temperature = 325.*kelvin; G4double pressure = 50.*atmosphere;
G4Material* CO2 = new G4Material(“CarbonicGas", density,
ncomponents=2 kStateGas, temperature, pressure); CO2->AddElement(C,natoms = 1); CO2->AddElement(O,natoms = 2);
Define detector geometryDefine detector geometryDefine detector geometryDefine detector geometry
G4Box
G4Tubs
G4VSolid G4VPhysicalVolume
G4Material
G4VSensitiveDetector
G4PVPlacement
G4PVParameterised
G4VisAttributes
G4LogicalVolume
Three conceptual layers– G4VSolid -- shape, size– G4LogicalVolume -- daughter physical volumes, material, sensitivity, user limits, etc.– G4VPhysicalVolume -- position, rotation
Parameterised Physical VolumesParameterised Physical VolumesParameterised Physical VolumesParameterised Physical VolumesUser written functions define:
– the size of the solid (dimensions)Function ComputeDimensions(…)
– where it is positioned (transformation)Function ComputeTransformations(…)
Optional:– the type of the solid
Function ComputeSolid(…)– the material
Function ComputeMaterial(…)
Limitations:– Applies to simple CSG solids only– Daughter volumes allowed only for special cases
Very powerful– Consider parameterised volumes as “leaf” volumes
G4PVParameterisedG4PVParameterisedG4PVParameterisedG4PVParameterisedG4PVParameterised(const G4String& pName, G4LogicalVolume* pCurrentLogical, G4LogicalVolume* pMotherLogical, const EAxis pAxis, const G4int nReplicas, G4VPVParameterisation* pParam);
Replicates the volume nReplicas times using the parameterisation pParam, within the mother volumeThe positioning of the replicas is dominant along the specified Cartesian axis
– If kUndefined is specified as axis, 3D voxelisation for optimisation of the geometry is adopted
Represents many touchable detector elements differing in their positioning and dimensions. Both are calculated by means of a G4VPVParameterisation objectAlternative constructor using pointer to physical volume for the mother
Hounsfield UnitsHounsfield Units
Spettro non monocromatico
We must determine:
mass density ρ
and elemental
composition wi
VisualizationVisualization
Material HU interval
Air [−1000:−950]
Water/tissue [−950:125]
ICRP cortical bone [125: 2000]
Steel 3095
CQ: uniformityCQ: uniformity
Confronto tra numero CT medio di una ROI al centro
del fantoccio con quello delle ROI ai bordi del fantoccio
Valutazione della graduale variazione dei numeri CT in un fantoccio
omogeneo
CQ: CT numbersCQ: CT numbers
Inserti di differente materiale
con numeri CT variabili nel
range di interesse
INTEROPERABILITY & CONNECTIVITY
RadiotherapyRadiotherapy
Nuclear medcineNuclear medcineRadiologyRadiology
Medical PhysicsMedical Physics
CTCT RMRM SPECTSPECT
CTCT
PETPETDRDR
SimulatorSimulator
HIS/RIS/PACS
DICOM classDICOM classImage StorageImage Storage
Query / retrieveQuery / retrieve
PrintPrint
Worklist ModalityWorklist Modality
Performed Procedure Performed Procedure ModalityModality
DICOM objectDICOM objectCT, MR, NM, PT, SC, US, CT, MR, NM, PT, SC, US,
XA, DR….XA, DR….
The DICOM StandardThe DICOM Standard
DICOM covers:– Communication protocols over networks– File formats (on different types of media)– Information Object Definitions (content)– Services (functionality)– Grayscale display – Security – Hanging protocols– Structured reporting– Etc.
DICOM Functional Groupings
Media InterchangeMedia Interchange
Print ImagesPrint Images
Print ManagementPrint Management
Image Related Workflow andImage Related Workflow andInformation ManagementInformation Management
Query RequestQuery Request
Image Related Image Related Information TransferInformation Transfer
Persistent Object StoragePersistent Object Storage
Persistent Object StoragePersistent Object Storage
Retrieve Retrieve RequestRequest
Command
Patient Name
Patient ID
Rows
Columns
Bits Stored
…
Network Transfer
Data Set=
+
Meta Data +Media Transfer
Data Set=
Group 0 ( Describes Service: C-Store)
Group 2 ( Describes Data Set)
D I C O M [ . . . . . . . F I L E . . . . . . . . . . ]
D I C O M [ . . . . . M E S S A G E . . . . . . . ]
Header
Image
DICOM Transfer over Network & Media
DICOM Information Object Definitions
Image Image ModuleModule
Patient Patient ModuleModule
General General Study Study
ModuleModule
Patient Patient Study Study
Module*Module*
General General Series Series
ModuleModule
Frame of Frame of Reference Reference ModuleModule
General General Equipment Equipment
ModuleModule
General General Image Image
ModuleModule
Image Image Plane Plane
ModuleModule
ContrasContrast/Bolus t/Bolus ModuleModule
Overlay Overlay Plane Plane
Module*Module*
VOI VOI LUT LUT
ModuleModule**
SOP SOP CommoCommo
n n ModuleModule
Image Image Pixel Pixel
ModuleModule
Image Pixel Image Pixel ModuleModule
Image Pixel Image Pixel ModuleModule
Row/Col SizeRow/Col SizePhotometric InterpretationPhotometric Interpretation
Row/Col SizeRow/Col SizePhotometric InterpretationPhotometric Interpretation
Patient Patient InformationInformation
Study Study InformationInformation
Series Series InformationInformation
(Image) Information
InstanceInstance
Information
Entities
Modules Attributes
Network Addressing with DICOM Handshake Requirements
ID: CT_AE1IP: 10.3.253.8Port: 104
ID: WK_AE1IP: 10.3.253.9Port: 4006
IP Addr AE Title Port #
10.3.253.1 Fusion 104
10.3.253.9 WK_AE1 4006
IP Addr AE Title Port #
10.3.253.1 Fusion 104
10.3.253.8 CT_AE1 104
Association / Association / NegotiationNegotiation
CT Config FileCT Config File Wkstn Config FileWkstn Config File
Node Level Node Level SecuritySecurity
Typical Network Flow
DICOM AE “A”DICOM AE “A” DICOM AE “B”DICOM AE “B”A-ASSOCIATE-RQA-ASSOCIATE-RQ
A-ASSOCIATE-ACA-ASSOCIATE-AC
A-RELEASE-RSPA-RELEASE-RSP
A-RELEASE-RQA-RELEASE-RQ
Only The AE Which Initiated The Association May Release ItOnly The AE Which Initiated The Association May Release ItHowever, Either May Initiate An A-ABORTHowever, Either May Initiate An A-ABORT
Only The AE Which Initiated The Association May Release ItOnly The AE Which Initiated The Association May Release ItHowever, Either May Initiate An A-ABORTHowever, Either May Initiate An A-ABORT
ororA-ASSOCIATE-RJA-ASSOCIATE-RJ
DICOM MessagesDICOM Messages
ororA-ABORTA-ABORTEither AEEither AE
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