FDG-PET/CT Technical Committee

Quality Control Subcommittee

Goals

• Bridge the gap between PET/CT scanner acceptance/qualification/certification and routine (daily) quality control

• Summarize methods and parameters for evaluating daily PET and CT QC on each vendor’s PET/CT scanner

• Long term goal: Establish common standards for recording and distributing QC parameters for individual patient scans (e.g. extended DICOM tags)

Process

1. Identify the daily quality control tests that are performed on each vendor’s PET/CT scanners

2. Specify the range of acceptable parameters for each test as recommended by the vendor

3. Describe the methods for obtaining QC parameters and the output format for each vendor

4. Ideally, develop standard for daily QC output that could be exported with individual patient scan, e.g. extended DICOM tags or standard file format (CSV, XML)

CT Quality Control

• Siemens – automated test (pass/fail)– Check HU value of water.– Check pixel noise– Check tube voltages

• GE – manual test with acceptable range– Check mean CT value of water (range: 0 ±3

HU) in 3 ROIs of uniform section.– Check variance of water (range: 3 ±0.4) in 3

ROIs of uniform section

Siemens PET Quality Control

• Ge-68 cylinder compared to normalization standard– Visually inspect sinograms and fansums.– If a sinogram shows a dark or bright streak or

a “fansum” block is not uniform, notify physicist

– If Chi-square > 2.5, notify physicist. (Original limit, adopted as DFCI threshold.)

– If Chi-square > 10, call Service. Notify physicist

GE PET Quality Control

• Ge-68 pin source compare daily tests to baseline with color coded results (green/yellow/red)

– Coincidence mean (sensitivity test: Average of coincidences for all crystals)

– Coincidence variance– Singles mean (Average of singles for all crystals).– Singles variance– Mean deadtime (Average deadtime of all blocks).– Timing mean (Average timing adjustment of all crystals)– Energy shift (Average difference in energy peak location)

QC Output formats

• Mostly based on visual display

• Siemens has some files available in html format on local folder

• GE results can be printed as postscript

Resources Needed

• Information about Philips Daily QC from end users and vendor

• Additional clarifications from GE and Siemens

• Feedback from RSNA QIBA members

• Potential interactions with DICOM working group to discuss inclusion of QC results