Options

The options dialog appears as (see color demo)

hot iron fused display - in addition to the blue fusion display, there is also hot iron

display operator name - the tech who collected the study

auto resize window to fit data - used when MIP is released, causing a window resize

The Auto start allows for automatically starting Annotations and/or Brown fat, ROIs. These will be started only if the study includes the relevant data. It is a convenience used to save a couple of mouse clicks.

SUVmax diameter in mm, use sphere show circle

Use sphere is an option to calculate the SUV using a sphere. The default is to use the in plane data, so "What you see is what you get". Using a sphere adds the 3rd dimension but may confuse you in that data which you cannot current see affects the result. Show circle replaces the usual cross hairs which mark the center of the SUV, by a circle whose size is determined by the SUV size you chose.

There are 2 versions of SUVpeak. The first is the classic version by Wahl which is the SUVmean in a 1 cc volume centered on SUVmax.

There is also SUVqpeak (qPET peak) which in qPET - a quantitative extension of the Deauville scale... is defined as the average of SUVmax together with the 3 hottest pixels in a 1 cc volume, centered on SUVmax. Both versions reduce the statistical fluctuation of a single pixel SUVmax.

Finally there is SUVmean which is the average of all pixels in the ROI.

There is a 2nd line of ROI definitions. In this example it is SUVmean. It can be chosen by a right click on the PET popup menu. This may be useful when most of the time you wish to see SUVmax values, but sometimes you want to see SUVmean in the liver for a background value. Each case can have its own circle/sphere diameter and you can have the cursor look different in both cases by clicking Show circle differently.

Right click - Slice max factor - when you right click on the PET image, one of the options is Slice max. In certain cases it might be preferred to see the data scaled to something greater than the max.

PgUp, PgDn is used with the Page up/down keys to skip up to 20 slices at a time. The arrow up and down keys skip one slice at a time. Holding down the keys will cause a rapid scroll, so there is no need for multiple clicks.

ignore SUV allows the use of original manufacturer units, in place of SUV. In many cases the original manufacturer units are Bq/ml, but not in all cases. It is up to the user to be aware of what the manufacturer uses. Since the units are "unknown" to the system the label Counts is used.

Why would someone want to use ignore SUV? Iodine-124 decays with a half life of 4.1 days. The biological wash out is much faster than the half life, so the SUV is expected to be valid only up to about 24 hours. After that it makes more sense to use the manufacturer original units (most likely Bq/ml).

Black background - if you prefer a black background instead of the default white.

best quality, z > 2.0 mm is used to select tricubic interpolation for a professional display. If this is not checked bicubic interpolation will be used. The tricubic is felt in the coronal and sagittal views. Both intepolations are done at load time.

What about weak hardware? Both interpolations take time, with tricubic taking more time. What if speed of loading is more important than display quality? The trick is to change the 2.0 mm to something big like 20.0 mm. Irrespective if best quality is checked or not a large value in resolution will kill both interpolations, which is more convenient for relatively weak hardware.

There is a panel LUTs - updated on next start of Pet Ct Viewer, which allows you to change the default look up tables. The default LUTs are based upon GE equipment which is the environment where the software was developed. Since your environment may be another manufacturer, you may be used to different LUTs, and this allows you to change the defaults. In additional LUTs there are some LUTs which you may use.

The first two The blues and Hot iron appear in the popup menu with these names. Clearly, if you change the default LUTs, you would also like to change what appears in the popup menu. So you can replace The blues and Hot iron by other names which more clearly indicate the actual type of LUT.

There is a before each of the entries. This determines if the replacement is used or not, i.e. you can define alternative LUTs and then decide to use the defaults simply by unclicking .

Fixed user LUT. In the popup menu there is Use source. In the default case where the feature is not chosen, this uses whatever look up table is set for the postage stamp input data. This is very useful for testing new LUTs. Once you have decided that there is one LUT which is really useful, you can avoid the step of setting the input data to that LUT.

In all 4 cases you check the box and browse to the appropriate LUT. You press Save as defaults to store it. All 4 LUTs together with Black background and ignore SUV take effect only after you restart the Pet Ct viewer.

The buttons Save as defaults and Temporary determine whether what you just chose will be used only as temporary, experimental values or will be used as permanent values.

Under File there is Save Significant Image to save the current image for future reference. Directory for Significant Image defines the path where all significant images will be stored. There is a browse button and also a spinner control. The spinner allows up to 10 paths, where you can easily switch from one to another to change the destination of the significant image. If you wish to save the significant images directly to the PACS, look at dcm4chee for the BI database, Setup tab.

In the screen shot above you might notice that the spinner in on 2. This is a directory on my local disk. Spinner=1 happens to be ORTHANC@192.168.0.100:4242 which is location of Orthanc on my LAN.

You are free to make any mix of directories, both local and remote, as well as Dicom addresses. Put them in any order you like. The most logical choice the order of preferred use, perhaps with the Dicom PACS at 0, the most important position on the list. Obviously you can't use the browse button for Dicom destinations. You need to contact your administrator to know the exact format for the particular Dicom destination.