MOSAIQ User's Guide - UCSF Radiation Oncology

MOSAIQ User’s Guide
Excluding Session Offset
You might reject a recorded treatment session offset for trend analysis based on the following
reasons:
Do not include offsets recorded from post correction or confirmation imaging when
you calculate a Localization Offset.
Do not include offsets recorded at different setup positions.
Other reasons might include rejection of the image set by the physician, known poor patient
positioning, patient motion, or other setup complications.
Click the Exclude check box in the Localization Trend Review dialog box to remove a
Session Offset from trend analysis.
Localization Offset
Derive Localization Offset Button
When you correct for systematic variation, you set up the patient more precisely and can
reduce the frequency of repeat imaging. When you see a trend in the shift data, you can
manually specify an offset in the Additional group of the Localization Trend Review dialog
box. You can also click the Derive Localization Offset button to calculate the average
session offset of all tagged Session Offsets. The calculated average is shown in the Additional
group. You can manually change the calculated values before you click OK to save them.
You can see recorded results of five image registrations for the same treatment site for this
patient. No Current Localization Offset shows.
1. Click the offsets you want to include in the calculation, then press the SPACEBAR to
tag them. You can also click in the far left margin of each offset row.
2. Click Derive Localization Offset to calculate the average offset of the tagged sessions.
The data appears in the Additional group of the Localization Trend Review dialog box.
The “new” Localization Offset shows in the Setup Alert dialog box after you save
pending changes.
The data shows a superior/inferior offset value of 0.0. Since the average is Inf average is
0.1 and the offset is 0.1.
The data shows left and right offset values from Lt 0.3 to Lt 0.8 for each treatment day.
The average is Lt 0.5.
The data shows posterior offset values from Pos 0.6 to Pos 1.2. The average is Pos 0.9.
The Current group shows any Localization Offset in use. These offset values are for
reference MOSAIQ adds the entries in the Additional column to create a New
Localization Offset.
The Additional group is for changes to the existing Localization Offset.
The New group shows what the Localization Offset will be after you click OK. Setup
Intelligence lets you change the Localization Offsets as often you need to over the course
of treatment.
Saved Localization Offsets appear next to the Prescribed Relative Offsets in the
Treatment Field Definition dialog box, pre-treatment Setup Alert, and the Setup view of
the Verified Treatment dialog box. The Total Offset apply after you align the patient
214 Copyright 2010, Elekta Impac Software
LUGMSQ0002/4.0/23-Sep-2010