Z. You et al.: Radioprotection 2025, 60( 1), 20 – 27 21
these interventions result in varying radiation doses across different locations within the cardiac catheterization room and the radiation doses to the operator and nurses are dynamically changing. This study aims to analyze radiation dose levels in 22 specific areas under eight projection angles of the DSA machine, offering radiation protection strategies for operators and nurses.
2 Material and methods
The brand of DSA machine used in this study was PHILIPS, model number UNIQ FD20, X-ray tube model number MRC 200 0407; one standard manikin simulating the patient and two ordinary manikins simulating the first operator and the second operator were used; the radiation dosemeter brand is RAYCAN, the model was RadTarger, and the calibrated radiation unit was mSv; the brand of radiation protective clothing used was KangHun lead-free radiation protective clothing, and the lead equivalent was 0.5 mmPb; the brand of ceiling suspension lead screen and under- operating table lead curtain used was Huaren, and the lead equivalent was 0.5 mmPb.
In this study, the DSA machine acquisition mode was set to cine acquisition CardFixed, the tube voltage was 73 kV, the acquisition frame rate was 15 fps / s, and the vision of the flat-panel receiver was 20 20 cm. The projection angles of theDSAmachineusedinthestudyaredividedinto8types, namely:( 1) The right front oblique position( RAO 30 °);( 2) The liver position( RAO 30 ° CAU 20 °);( 3) The right shoulder position( RAO 30 ° CRA 20 °);( 4) The head position( CRA 30 °);( 5) The left shoulder position( LAO 45 ° CRA 20 °);( 6) The left front oblique position( LAO 45 °);( 7) The spider position( LAO 45 ° CAU 20 °);( 8) The foot position( CAU 30 °).
The patient’ s manikin was placed on the midline of the operating table to simulate the conventional thoracoabdominal position of the patient in the cardiac catheterization interventions. A parallel line of the longitudinal axis of the body was drawn 10 cm medial to the left anterior axillary line of the patient manikin, and a parallel line of the transverse axis was drawn 20 cm below the left shoulder, and a steel ball of approximately 1 cm 3 in size was placed at the intersection of the two lines and set as the heart center. Perform the following at each projection angle, lower the flat-panel receiver and the operating table to the lowest point and move the operating table so that the central area of the heart, i. e., the steel ball, is in the center of the vision of the flat-panel receiver. The first operator manikin was placed close to the operating table in the usual puncture standing area for cardiac catheterization interventions, i. e., the patient’ s right radial artery puncture position, and the second operator manikin was placed close to the operating table in the position of the DSA machine operating panel, and both operator manikin were routinely wear radiation protective clothing, In addition, the ceiling suspension lead screen is close to the first operator manikin, and the lower edge is close to the operating table. This placement method has been proven to have a better radiation protection effect( Fetterly et al., 2011).
In this study, the floor of the cardiac catheterization room was gridded by different partition lines, dividing the room into a total of 22 areas, see Figure 1, where area( 11) and area( 15) are set as the first operator and second operator standing areas.
Radiation dose collection method is as follows: the center of each area, 1.6m height position set as a measurement point, a total of 22 measurement points, in the measurement point at the placement of the radiation dosimeter, the DSA machine using the cine mode release 5 times, each release 10s, to be radiation dosimeter stabilized to take the value, each area to collect to 5 dose values. In order to prevent overloading of the x-ray tube, the next area radiation dose collection is started again at an interval of 1 minute, each projection angle can be collected to 110 radiation dose, a total of 880 radiation dose values can be collected.
All data in this study were processed in SPSS 26.0, and the radiation dose of the 22 areas under each projection angle conformed to normal distribution by Kolmogorov – Smirnov test, described by mean ± sem. One-way analysis of variance( ANOVA) was used for comparison of radiation dose values in 22 areas at the same projection angle and for comparison of radiation dose values in the same area at different projection angles, Under the same projection angle, the comparison of radiation dose in the 2 areas was performed by independent sample t-test. p < 0.05 was considered a statistically significant difference.
3 Results
The radiation dose of 22 areas under 8 projection angles is shown in Figure 2.
Among them, an analysis of the radiation dose in 22 areas with 8 projection angles revealed that the lowest radiation dose( p < 0.05) was found in the areas( 19) in the right anterior oblique position( RAO 30 °), liver position( RAO 30 ° CAU 20 °), right shoulder position( RAO 30 ° CRA 20 °), and foot position( CAU 30 °); the lowest radiation doses( p < 0.05) was found in the area( 18) in the left shoulder position( LAO 45 ° CRA 20 °) and the spider position( LAO 45 ° CAU 20 °); the lowest radiation dose( p < 0.05) was found in the areas( 21) in the left anterior oblique position( LAO 45 °); the lowest radiation dose( p < 0.05) was found in the areas( 20) in the cephalic position( CRA 30 °); the highest radiation dose( p < 0.05) was found in the areas( 7) in the right anterior oblique position( RAO 30 °), liver position( RAO 30 ° CAU 20 °), right shoulder position( RAO 30 ° CRA 20 °), and head position( CRA 30 °); the highest radiation dose( p < 0.05) was found in the areas( 8) in the left anterior oblique position( LAO 45 °), left shoulder position( LAO 45 ° CRA 20 °), spider position( LAO 45 ° CAU 20 °) and foot position( CAU 30 °), as shown in Figure 3.
Analysis of the radiation dose in area( 7) and area( 11) shows that the radiation dose in area( 7) is greater than the radiation dose in area( 11) at all projection angles( p < 0.05). When analyzing the radiation dose in area( 11) and area( 15), it was found that the radiation dose in area( 15) was greater than that in area( 11) at all projection angles( p < 0.05), as shown in Figure 4.
In the analysis of the radiation dose in area( 11) and area( 15) at eight projection angles, it was found that area( 11) had the highest radiation dose( p < 0.05) in the cephalic position( CRA 30 °), and area( 15) had the highest radiation dose( p < 0.05)