Radiation Control, X-ray Unit
625 North Robert Street
PO Box 64497
St. Paul, Minnesota 55164-0497
651-201-4545
www.health.state.mn.us/xray
[email protected]
SELF-REFERRAL SCREENING
2012 CT ANNUAL REPORT
Registrants approved by Minnesota Department of Health (MDH) to perform Computed
Tomography (CT) Cardiac, Lung, and/or Colon self-referral screening annually provide the
following data within this report. Individuals are encouraged to use this data for developing
new self-referral screening programs or reviewing current screening practices relative to
patient exposures and ALARA principles.
SELF-REFERRAL
SCREENING PROGRAM
BACKGROUND INFORMATION
ANNUALLY
REQUESTED
DATA:
● Number of CT self-referred
patients screened for each
If an individual wishes to have an examination not ordered by a
licensed practitioner of the healing arts, MDH regulates the program
designed and equipment used to detect or evaluate specific health
conditions. An application and approval from the Commissioner is
required before these examinations can be performed. The regulations
governing self-referral screening are contained in the Ionizing Radiation
Rules, Chapter 4732.
type of examination per
When a patient chooses to be screened without consulting a licensed
practitioner of the healing arts, it is particularly important to protect
individuals from unnecessary radiation exposure resulting from CT selfreferral screening examinations. The registrant must provide MDH with
nationally recognized standards or copy of site specific guidelines and
criteria the organization follows for each area performing CT selfreferral screening. MDH reviews the determinants used for selection of
patients to be screened.
examination
Every reasonable effort should be made to maintain radiation
exposures as low as is reasonably achievable (ALARA). The registrant
should consider the ALARA philosophy in the development of work
plans involving the procedure and protocol used for CT self-referral
screening examinations.
Registrants must provide assurance that the operator, patient, and
member of the public are not receiving unnecessary radiation exposure
by testing equipment at regular intervals. Equipment Performance
Evaluations (EPE) are required at intervals not to exceed 12 months
because of the complexity and higher output of these units. The only
individuals authorized to assess the performance measurements on CT
scanners performing CT self-referral screening are diagnostic
radiologic physicists.
The registrant must submit as part of the screening application, the
calculation of each screening study using the CTDI-vol output value
from each CT unit performing self-referral screening examinations. The
CTDI-vol output values are based on the factors programmed within the
scanner.
calendar year
● Number of positive results
for each type of screening
● Type of scanner used in
performing these
examinations by detector
configuration (slice)
● Average total dose length
product given to the patient in
mGy-cm for each detector
configuration (slice)
2012 ANNUAL SCREENING QUESTIONAIRE
Registrants approved by MDH to perform CT self-referral screening receive an annual questionnaire in
January to collect data regarding self-referral screenings performed the previous year. The major
components of this questionnaire include the number of CT self-referred patients screened for each
type of examination, number of positive results for each type of screening examination, type of scanner
used in performing these examinations by detector configuration (slice), actual CTDI-vol in mGy
calculated from factors programmed in CT scanner, and average total dose length product given to the
patient in mGy-cm for each detector configuration (slice).
Number of CT self-referred patients screened for each type of examination
Minnesota had a total of 38 approved screening locations in 2012. Of the 38 self-referral screening
locations; 29 were approved for Cardiac, 26 were approved for Lung, and 14 were approved for Colon.
Data collected from all approved self-referred screening locations indicated a combined total of 1,911
examinations for all screening areas.
Cardiac CT self-referred screening was identified as the predominant examination in Minnesota. Total
CT self-referral screening examinations performed in 2012 was 1,911; 1,842 of the exams were
Cardiac, 22 of the exams were Lung, and 47 of the exams were Colon. The data is represented in the
graph below.
MDH CT Self-Referral Screening
Lung
1%
Colon
3%
Cardiac
96%
Number of positive results for each type of screening examination
The annual questionnaire requests the number of examinations that were interpreted with a positive
finding for each area approved, i.e. Cardiac, Lung, and Colon. The registrant determines the extent to
which an examination is considered positive.
Data analysis of the 1,842 Cardiac self-referral
examinations indicated 1,028 with a positive
finding. The chart to the right is a graphical
representation of the data.
Cardiac Self-Referral
Screening
Postive
results
56%
Lung Self-Referral
Screening
Positive
results
45%
Negative
results
44%
Data analysis of the 22 Lung self-referral
examinations indicated 10 with a positive
finding. The chart to the left is a graphical
representation of the data.
Negative
results
55%
Data analysis reported of the 47 Colon selfreferral examinations indicated 18 with a
positive finding. The chart to the right is a
graphical representation of the data.
Colon Self-Referral
Screening
Positive
results
38%
Negative
results
62%
Scanner, CTDI-vol (mGy), & Dose Length Product
The annual questionnaire requests the manufacturer of the primary unit performing CT self-referral
screening by detector configuration (slice). The registrant will also indicate if the primary unit uses dose
reduction software for the programmed self-referral screening protocol and/or gating capabilities.
The survey requests the average dose length product given to the patient in mGy-cm for each detector
configuration (slice). As a part of the annual application, self-referral screening applicants are required to
submit an actual CTDI-vol in mGy calculated from factors programmed in CT scanner. All data
represented below are averaged.
CARDIAC
Of 38 approved screening locations, 29 scanners actively performing Cardiac self-referral screening.
•
9 Siemen scanners – 9 use dose reduction software
- 3 Siemens 64 include gating
- 3 Siemens 128 include gating
•
19 GE scanners – 12 use dose reduction software
- 1 GE 4 include gating
- 1 GE 8 include gating
- 4 GE 16 include gating
- 2 GE 64 include gating
•
1 Philip scanner – 1 use dose reduction software and gating
Cardiac Siemens CTDI-vol
Cardiac Siemens DLP
140
8
120
6
100
80
4
60
40
2
0
20
Siemens 16
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
Siemens 64
4.79
4.79
4.79
Siemens 128
3
4.73
7.7
1.6
5.19
7.92
0
Siemens 16
● Min DLP
● Average DLP
● Max DLP
Siemens 64
66
66
66
Siemens 128
42
69.5
116.6
30
84.84
124
Cardiac GE CTDI-vol
Cardiac GE DLP
20
300
250
15
200
10
150
100
5
50
0
GE 4
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
GE 8
9.86
11.06
11.67
GE 16
10.58
10.58
10.58
0
GE 64
3.55
7.27
19.65
3.59
7.06
8.99
GE 4
● Min DLP
● Average DLP
● Max DLP
GE 8
175
177
178
GE 16
96
96
96
GE 64
70
152.08
265.53
Cardiac Philips DLP
Cardiac Philips CTDI-vol
60
6
50
40
4
30
2
20
10
0
0
Philips 64
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
5.8
5.8
5.8
● Min DLP
● Average DLP
● Max DLP
Philips 64
54
54
54
LUNG
Of 38 approved screening locations, 22 scanners actively performing Lung self-referral screening.
•
•
4 Siemen scanners – 4 use dose reduction software
18 GE scanners – 11 use dose reduction software
46.28
82.71
112
Lung Siemens CTDI-vol
Lung Siemens DLP
7
350
6
300
5
250
4
200
3
150
2
100
1
50
0
Siemens 16
Siemens 64
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
4.7
4.8
4.9
0
Siemens 128
4.56
4.56
4.56
6.85
6.85
6.85
Siemens 16
Siemens 64
● Min DLP
● Average DLP
● Max DLP
Lung GE CTDI-vol
339
343.5
348
Siemens 128
126
126
126
247.5
247.5
247.5
Lung GE DLP
140
20
120
15
100
80
10
60
40
5
20
0
GE 4
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
GE 8
1.8
3.27
4.17
GE 16
7.96
7.96
7.96
0
GE 64
1.14
3.75
19.65
2.6
3.27
3.94
GE 4
● Min DLP
● Average DLP
● Max DLP
GE 8
54.6
97.9
125
GE 16
112.5
112.5
112.5
GE 64
47.22
58.47
94.78
69.19
93.6
118
COLON
Of 38 approved screening locations, 13 scanners actively performing Colon self-referral screening.
•
•
1 Siemen scanner – 1 use dose reduction software
12 GE scanners – 11 use dose reduction software
Colon Siemens CTDI-vol
Colon Siemens DLP
8
200
6
150
4
100
2
50
0
0
Siemens 16
Siemens 16
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
● Min DLP
● Average DLP
● Max DLP
7.1
7.1
7.1
Colon GE CTDI-vol
Colon GE DLP
12
1000
10
800
8
600
6
400
4
200
2
0
181.64
181.64
181.64
GE 4
● Min CTDI-vol
● Average CTDI-vol
● Max CTDI-vol
GE 8
7.3
8.45
9.6
GE 16
4.06
4.06
4.06
0
GE 64
3.04
5.52
10.19
11
11
11
GE 4
● Min DLP
● Average DLP
● Max DLP
*The Colon DLP is reported combining both supine and prone imaging.
GE 8
272
520
768
GE 16
414
414
414
GE 64
181.64
211.7
268
880
880
880