Возможно, адреса электронной почты являются анонимными для этой группы или вам требуется разрешение на просмотр адресов электронной почты ее участников, чтобы увидеть исходное сообщение.
Hi,Возможно, адреса электронной почты являются анонимными для этой группы или вам требуется разрешение на просмотр адресов электронной почты ее участников, чтобы увидеть исходное сообщение.
"Ing. Tommaso Sansoni" wrote in message news:.The UID is generated the same as any other DICOM UID. You can find aHere's a brief extract from that write up:
Each UID is composed of two parts, an and a :
UID = .
The portion of the UID uniquely identifies an organization,
(i.e., manufacturer, research organization, NEMA, etc.), and is
composed of a number of numeric components as defined by ISO 8824. The
portion of the UID is also composed of a number of numeric
components, and shall be unique within the scope of the .
This implies that the organization identified in the is
responsible for guaranteeing uniqueness by providing
registration policies. These policies shall guarantee
uniqueness for all UID's created by that organization. Unlike the root>, which may be common for UID's in an organization, the
shall take different unique values between different UID's that
identify different objects.
The frame of reference UID is used in different images to identify
themselves as having be acquired in a specific coordinate reference.
For example in a CT or MR exam, before the patient is imaged, the
technician will "landmark" the patient. This involves positioning the
modality table ( the platform on which the patient lies that moves the
patient into and out of the imaging device) to a position where some
portion of the patient's anatomy is at a known position. Often there
is laser crosshair which is positioned on the patient's forehead. When
the "landmark" is establish, this becomes the zero point in the
coordinate space for the frame of reference. During the exam, as the
patient is moved into the imaging device, the modality can keep track
of where in the coordinate space, the table (and patient) is currently
positioned. The images are tagged with an offset from the zero point.
Also with orientation angles relative to plane of the patient and
table. As a receiver of the images, you the various image position
coordinate values and angles in the different images (which may also
be in different series). With the Frame of reference UID, you know the
image position coordinates are all relative to the same calibrated
origin point. There are also frame of references relative to temporal
coordinates but the same principals apply. The same FOR UID value in
different dicom objects tells you that the other attributes
identifying the image location in time or space are relative to the
same calibrated origin/measurment device, whether it is a clock, table
position, gantry position, etc.
Возможно, адреса электронной почты являются анонимными для этой группы или вам требуется разрешение на просмотр адресов электронной почты ее участников, чтобы увидеть исходное сообщение.
Eric_G. @hotmail.com (Eric Goodall) wrote in message
> The frame of reference UID is used in different images to identify
> themselves as having be acquired in a specific coordinate reference.
> For example in a CT or MR exam, before the patient is imaged, the
> technician will "landmark" the patient.
> patient is moved into the imaging device, the modality can keep track
> of where in the coordinate space, the table (and patient) is currently
> positioned. The images are tagged with an offset from the zero point.
> Also with orientation angles relative to plane of the patient and
> table. As a receiver of the images, you the various image position
> coordinate values and angles in the different images (which may also
> be in different series). With the Frame of reference UID, you know the
> image position coordinates are all relative to the same calibrated
> origin point.
This is all correct, but I just wanted to point out that DICOM does
not define any "origin point": all the images that share the same FoR
UID belong to the same frame of reference, that is their Image
Position (Patient) (0020,0032) and Image Orientation (Patient)
(0020,0037) are spatially related, that is the coordinates x,y,z of
the upper-left pixels, and the direction cosines of the rows and
columns of the images, in the x,y,z space, are coherents together.
The x,y,z directions of the frame of reference are instead strictly
related to the human anatomy: "The x-axis is increasing to the left
hand side of the patient. The y-axis is increasing to the posterior
side of the patient. The z-axis is increasing toward the head of the
patient." (see PS3.3-2003, C.7.6.2.1.1 Image Position And Image
Orientation, page 237).
As you can find, nothing is said about the origin of the frame of
reference.
In practice, the modality calculates (in a very precise way, related
to the acquisition mechanism) the position and orientation of the
images in its own frame of reference, then applies a frame of
reference change according to the position of the bed, the orientation
of the patient on it (supine, prone, decubitus left or right), and the
position of the (self-defined) origin of the chosen final FoR.
If the patient is manually moved on the bed, normally a new FoR should
be started: I do not think that using the laser beam centered on the
forehead of the patient can give precision enough to spatially relate
the images before and after the manual movement of the patient.
========================================================
Luigi Pampana-Biancheri, BS in Physics
Esaote S.p.A. - DICOM and Connectivity Management (EDMG)
Возможно, адреса электронной почты являются анонимными для этой группы или вам требуется разрешение на просмотр адресов электронной почты ее участников, чтобы увидеть исходное сообщение.
There is a significant new DICOM feature released this year
related to spatial frames of reference: Supplement 73 Spatial
Registration Storage SOP Classes.
ftp://medical.nema.org/medical/dicom/final/sup73_ft4.pdf
Sup73 allows specifying the spatial relationship between one
frame of reference and another, either by spatial fiducials (such
as anatomical landmarks), or by transformation matrices.
Sup73 has also created UID's for "well-known" frames of reference
for anatomical and functional brain data: Talairach, SPM and ICBM.
"Luigi Pampana-Biancheri" wrote in message
news:ef973c2b.04041. @posting.google.com.
Возможно, адреса электронной почты являются анонимными для этой группы или вам требуется разрешение на просмотр адресов электронной почты ее участников, чтобы увидеть исходное сообщение.
Perhaps an unfortunate choice of words "origin point". The laser
pointers are really just to ensure consist landmarking of the same
point on the patient. The actual measured landmark is relative to some
mechanical measuring device internal to the modality. Yes the cosine
angles of the image orientation and coding of the patient position
"HFS" (head first supine) FFS (feet first supine, FFP Feet first
prone, etc) establish a common frame of reference to provide a common
orientation of the images in a 3d or 4d (time) space. But I believe
the frame of reference also includes the slice position. So the three
images selected from this CT exam have slice locations relative to the
position of the table when the patient was landmarked. For the slice
location at least, that does establish the position of each slice
relative to a common "point of origin". I've always understood the
fact that these images all contain the same FOR UID value establishes
their slice locations are relative to the same origin point, even
though that point has nothing to do with a specific location on the
patient's anatomy. Its just an arbitrary point in space that
establishes the relative location of the images with respect to each
other.
(0020,000D) UI Study Instance UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.131
(0020,000E) UI Series Instance UID
1.2.528.1.1001.100.3.481.426.20001012038.20020604225136771
(0020,0010) SH Study ID 4383
(0020,0011) IS Series Number 2
(0020,0012) IS Acquisition Number 47
(0020,0013) IS Instance Number 1
(0020,0032) DS Image Position (Patient)
-125.000000\-128.100006\-110.000000
(0020,0037) DS Image Orientation (Patient)
1.000000\0.000000\0.000000\0.000000\1.000000\0.000000
(0020,0052) UI Frame of Reference UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.132.11.2486.0
(0020,1040) LO Position Reference Indicator OM
(0020,1041) DS Slice Location -110.000000
(0020,000D) UI Study Instance UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.131
(0020,000E) UI Series Instance UID
1.2.528.1.1001.100.3.481.426.20001012038.20020604225136771
(0020,0010) SH Study ID 4383
(0020,0011) IS Series Number 2
(0020,0012) IS Acquisition Number 47
(0020,0013) IS Instance Number 2
(0020,0032) DS Image Position (Patient)
-125.000000\-128.100006\-111.250000
(0020,0037) DS Image Orientation (Patient)
1.000000\0.000000\0.000000\0.000000\1.000000\0.000000
(0020,0052) UI Frame of Reference UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.132.11.2486.0
(0020,1040) LO Position Reference Indicator OM
(0020,1041) DS Slice Location -111.250000
(0020,000D) UI Study Instance UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.131
(0020,000E) UI Series Instance UID
1.2.528.1.1001.100.3.481.426.20001012038.20020604225136771
(0020,0010) SH Study ID 4383
(0020,0011) IS Series Number 2
(0020,0012) IS Acquisition Number 47
(0020,0013) IS Instance Number 3
(0020,0032) DS Image Position (Patient)
-125.000000\-128.100006\-112.500000
(0020,0037) DS Image Orientation (Patient)
1.000000\0.000000\0.000000\0.000000\1.000000\0.000000
(0020,0052) UI Frame of Reference UID
1.2.840.113619.2.55.1.1762895081.2066.1022991499.132.11.2486.0
(0020,1040) LO Position Reference Indicator OM
(0020,1041) DS Slice Location -112.500000