Hologic - QDR Series FAQ

Analysis Questions

How do I find out what analysis options I have?
Highlight "Analyze" and press <Enter>, then select "Protocol" and press <Enter>. The analysis modes displayed represents the option available on your system for the current selected scan site.

How do I re-analyze a scan?
Select the desired scan, select "Analyze" twice. Then press <F10>.

How can I look at the analysis results without reanalyzing the scan?
Select the scan; select "Analyze" twice. The patient's results from the most recent analysis will appear on the monitor. If the scan had not been previously analyzed, you must first complete the analysis by placing the appropriate ROI or by comparing to a baseline scan if you are analyzing a follow-up scan.

How should I adjust the femoral neck when it does not fit in the space?
First, adjust the length (long axis) of the neck box using <page up> or <page down> keys and the left / right arrow keys. If necessary, also delete the ischium at the "Insert or Delete" step. If it still does not fit, shorten the width (short axis) of the neck box using the <page up> or <page down> keys and the left / right arrow keys.

Archiving Questions

Can I lose scans?
You can lose a scan if it is deleted without being archived first. You can also lose scans if your archive disk(s) are lost, damaged, or destroyed. This is the reason we recommend maintaining backup archive disks.

Compare Questions

How do I select the compare mode to analyze a follow-up scan?
Select the follow-up scan, select "Analyze", and then select "Compare". Highlight the baseline scan and press <enter>. The patient's follow-up scan will appear on the left side of the monitor and the image and ROI from the baseline analysis will appear on the right side of the monitor. Use the up / down / left / right arrow keys to move the yellow dotted outline (overlay) from the baseline scan to match the current scan as closely as possible and then complete the analysis according to instructions in the User's Guide.

If I have one or more follow-up scans, which do I compare to?
Always compare all follow-up scans to the initial baseline scan.

What if the follow-up scan does not match the original?
If the problem is due to poor patient positioning in the follow-up scan, re-position the patient and re-scan. If the problem is with the baseline scan, match the ROIs as closely as possible using the compare feature and complete the analysis.

Why can't I get a "rate-of-change" for my comparisons?
This is most likely because you have entered two biographies for the patient. The Hologic helpdesk will walk you through moving the scans into one biography and deleting the extra patient biography.

Can I use the "Compare" feature to compare a Pencil-Beam scan to a Fan-Beam scan?
No, you cannot use the "Compare" feature on unlike scan modes or on scans analyzed with different analysis protocols. You can, however, obtain a Rate-of-Change estimate on different scan modes. These estimates are generated with an asterisk to indicate that different scan modes (and possibly different scanners) were used to derive the estimates. Such estimates should be interpreted with caution. Call the helpdesk to walk you through these instructions.

When trying to use the "Compare" feature, I cannot put the pluses next to the previous scans. Why?
This is probably because the patient has two biographies. Call the Help Desk and they will step you through moving the scans into one biography.

Computer Questions

How do I change the time and the date on the computer?
At the Hologic mainmenu, press down on the <Alt> key and hold it. Press the <F1> key so they are both down at the same time and release. At the C:\menu prompt, type the word "date" or "time" and press <enter>. The screen will display the current date or time that the computer is set at. Type the correct date or time in the format displayed, then press <enter>. To return to the Hologic program, type "mainmenu" and <enter> at the C:\menu prompt.

General Info Questions

As an operator, if I am pregnant, should I use the shielding to protect me from the x-rays?
Contact your local radiation safety officer or state regulatory agency.

What are the power requirements for the QDR-4500?
Voltage is set at the factory, depending on country of destination. The power requirements for each voltage setting are the following:

100 VAC, 20 A, 50/60 Hz.
Maximum apparent resistance 0.32 ohms.

120 VAC, 15 A ,50/60 Hz.
Maximum apparent resistance 0.32 ohms.

230 VAC, 8 A, 50/60 Hz.
Maximum apparent resistance 1.28 ohms.
A dedicated circuit is required.

How do I clean the tablemat?
If cleaning is necessary, use water and a mild soap. Do not use anything with bleach in it, e.g. Wexcide, etc.

Reference Database Questions

How do I find out if I am using the NHANES Database?
If your system had NHANES data installed, "NHA 2/01/97" will be displayed under the T- and Z-score box for white male and female hip scans.

Why am I not getting Z-SCORES for my patient?
When reference data is not available for the patient's age, the Z-score cannot be calculated. For example, hip and forearm data is not available for patients under 20 or over 85 years. For patients under 20, Z-scores are only available for the L1-L4 region on AP lumbar scans.

Reporting Questions

Where do I type physician's comments?
At the "Normals" screen press the <Home> key. Then use the Insert key to highlight the desired comment(s). Pressing <ALT><T> at the same time will allow the user to enter their comments. All comments are stored with the scan archive.

Scanning Questions

I scanned the right hip using left hip mode, or vice versa. What should I do?
Delete the incorrect scan. Re-scan the patient using the correct scan mode.

What does "Motor At Limit" mean?
This message appears when the patient anatomy under study is beyond the active scan field and the c-arm encounters a mechanical stop. Reposition the patient so that the anatomy is within the active scan field and scan again. This is the only time that the <F3> repositioning function cannot reposition the arm.

Should I do a spine or hip scan on my patient?
Both scan modes are useful. The spine may be better for detecting early post menopausal bone loss and for monitoring BMD changes due to therapy or disease. Hip measurements may be indicated in elderly subjects who are at risk for hip fracture or where degenerative changes in the spine may falsely elevate an AP spine BMD measurement. The optimal choice of scan sites depends on the individual clinical situation of the patient. Consult the literature for further information on this topic, e.g. "Osteoporosis" Ed. by R. Marcus et al. published Academic Press 1996; "Bone Densitometry and Osteoporosis" Ed. by H.K. Genant et.al. pubished by Springer-Verlag 1998; "The evaluation of osteoporosis: Dual energy x-ray absorptiometry in clinical practice" by H.W. Wahner and I. Fogelman published by Martin Dunitz Ltd. 1994.

What is the Maximum Weight limit?
The maximum weight for the tabletop is 300 lbs.

Can I scan a patient with a pacemaker?
Yes.

Is it O.K. to scan a patient who took their calcium pill this morning?
A single 500mg or 1000mg calcium tablet is O.K., particularly if it is the chewable type. Subjects enrolled in a clinical research trial, which is powered to detect very small BMD changes, should not take calcium pills before an exam.

What are some of the conditions that may affect the results of a scan?
The most significant artifacts that interfere with densitometry results are radiographic contrast materials, such as barium or Isovue, and Nuclear Medicine scans, such as a Technetium 99 Bone scan. Patients who have such exams should wait at least 1 week before having a densitometry exam. For a more detailed list of possible interferences, please refer to your User's Guide.

Quality Control Questions

What are expected coefficient of variation(CV) values for the QC database?
BMD and BMC CV's should be less than 1%. More importantly, the long-term rate of change should be less than +/- 1% per year. The long-term rate of change is generated by pressing "r" at the screen where the QC data plot appears.

Is my QC okay?
Any obvious drift or plot outside the limit lines should be reported to the Hologic Help Desk. Also, if the rate of change is greater than 2%, and the error of the estimate is less than 2%, the results should be reported to the Hologic Help Desk. For a fuller discussion of QC, please see the Operator's manual.

Return to Top