2.1 Usage facilities for examination site
Komazawa University (1-23-1 Komazawa,
Setagaya-ku,
Tokyo,
Japan) and Shiga University of Medicine (1-1-1 Banba Hikone,
Shiga,
Japan) were used as testing venues for certifying lung cancer CT technologists.
The following three items were set as conditions for facility selection.
a.
Possible to accommodate more than 100 people:
b.
Setting a PC equivalent to corresponding to examinees (over 100 peoples):
and
c.
When geographically divided Japan into two halves,
it is located in the middle and the traffic access is good.
2.2 Study population and qualifications for examination
The present study analyzed data of 1593 examinees of the certification exam (exam of "1st to 17th"),
performed by the lung cancer CT certification organization.
The average number of years of experience of the examinees was 12.7 ± 7.
11 years (Maximum,
38 years; minimum,
2 years).
The basic requirements for technologists to perform the examination were as follows:
d.
Have acquired a radiological technologist's license; and
e.
Clinical practical experience as a radiological technologist for at least 2 years.
2.3 Examination method and system
The certification exam was conducted twice a year,
but at different venues each time.
The certification test consisted of two sections: a written test (25 questions,
60 min) ( Fig. 2 ) and an abnormal finding detection test (60 questions,
120 min) ( Fig. 3 ).
Written test was conducted on the physics of CT and the clinical practice of lung cancer as the subject of examination.
The abnormal findings detection test included normal cases.
In the preliminary guidance established for this study,
the detection point of abnormal findings was determined as "a nodule of 5 mm or more thought to be necessary for detailed examination".
In the abnormal finding detection test,
one server system was accessed by more than 100 client personal computers (PCs) (the number of clients corresponded to that of examinees).
For the examination,
a CT image viewer was installed on all PCs in advance.
The image displayed in this viewer was altered by scrolling the mouse,
and answers were recorded by marking (clicking) the area judged as an abnormal finding ( Fig. 4 ).
Then,
by clicking the "Next patient" tab for each case,
the image of the next case was automatically loaded.
It was possible to return to any case within the examination time and modify it.
After completion of the detection test,
answers were automatically collected and results were calculated.
2.4 Criteria of judgment (pass/fail)
The acceptance or rejection of the certification test was based on the sensitivity and Az value of the written test and the abnormal finding detection test result.
Conditions for certification were as follows:
f.
The percentage of correct answers in the written examination must be >60%;
g.
Detection sensitivity of “true positive” (TP) in the abnormal finding detection test must be >0.90; and
h.
The Az value in the area under the Receiver Operating Characteristic curve of the abnormal finding detection test must be >0.90.
2.5 Statistical Analysis
A regression analysis using an ordinary least squares method was performed for the pass rate against the average number of years of experience with written test and abnormal finding detection test.
The statistical significance of the TP and false positive (FP) values against the written test and abnormal finding detection test were explored using Welch’s t-test.
A two-sided P-value <0.05 was considered to be statistically significant.
All data were analyzed using the Tokei-Kaiseki version 2.0 and Tahenryo-Kaiseki version 2.0 for Mac software packages (Esumi Ltd,
Tokyo,
Japan).