ENH: update doc

diff --git a/Doc/HowToCorrelatePETCT.txt b/Doc/HowToCorrelatePETCT.txt
index 9f529752fe89c75077b1adbfe10c0188befe7624..1ba5617416260d166b6ba48444927aed1e4e39f2 100644 (file)
--- a/Doc/HowToCorrelatePETCT.txt
+++ b/Doc/HowToCorrelatePETCT.txt
@@ -1,8 +1,30 @@
-[Spatial Registration]
-http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/ab94a61d33082e29/d929474e92c30b24
-
+***************************
+- CT/PET Links:
 [Correlating CT and PT series]
 http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/50bd859e0232a735/6040b545240c8fa4
+Quote:
+For completeness, there are three ways an application can
+correlate CT and PET (or other sets) using DICOM only:
+
+1) Code all the images with the same Frame of Reference UID.
+At least one major vendor does this now.
+
+2) Make assumptions based on specific implementation behavior
+based on data elements that match (e.g. perhaps Study Time, or
+matching values in the General Equipment Module).
+Without actual trial and experience verifying the correlation,
+I agree, that an assumption is not wise
+
+3) Use the recent Supplement 73 Spatial Registration Storage SOP Classes.
+This capability allows explicitly specifying the spatial transformation
+from one Frame of Reference to another. However, this supplement
+is probably too recent to be in use. 
+
+[Is there a SOP class for CT-PET images?]
+http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/bb96abb730624a8a/5a78f1ff0199a727
+
+[Everything you have always hated about the DICOM PET SOP Class, but were afraid to ask]
+http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/dc3a07d4999445ae/560fd0a064145d61
 
 [fMRI Dicom objects]
 http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/30897c138442daad/27382b21968ce0b3
@@ -17,15 +39,16 @@ applications. See:
 ftp://medical.nema.org/medical/dicom/supps/sup73_05.pdf
 broken link use instead: ftp://medical.nema.org/medical/dicom/final/sup73_ft4.pdf
 
+[4 PET/CT questions]
+http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/56d07d5686e2ec67/b4c131f3e711716f
+
 
-[Everything you have always hated about the DICOM PET SOP Class, but were afraid to ask]
-http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/dc3a07d4999445ae/560fd0a064145d61
+***************************
+- Spatial registration oriented:
+[Spatial Registration]
+http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/ab94a61d33082e29/d929474e92c30b24
 
 [presentation context ID]
 http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/a4bb2647d5a91001/d0fbff58a644ce7c
 
-[4 PET/CT questions]
-http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/56d07d5686e2ec67/b4c131f3e711716f
 
-[Is there a SOP class for CT-PET images?]
-http://groups.google.com/group/comp.protocols.dicom/browse_thread/thread/bb96abb730624a8a/5a78f1ff0199a727