Reducing Fluoroscopic and Cineangiographic Contribution to Radiation Exposure for Chronic Total Coronary Occlusion Interventions.

BACKGROUND: The treatment of chronic total coronary occlusions (CTO) carries the highest radiation exposure among percutaneous coronary interventions (PCI). In order to minimize radiation damage, we need to understand and optimize the contribution of all components of radiation exposure. METHODS: A total of 1000 CTO procedures performed between 2011 and 2020 were compared according to implemented radiation modifications. Group 1 used the original set-up of the X-ray equipment (Artis Zee, Siemens). In group 2 a modified protocol aimed at reducing the fluoroscopy exposure, in group 3 further modifications aimed at reducing cineangiographic exposure. RESULTS: Despite an increased lesion complexity, Air Kerma (AK) was reduced from 2619 mGy (1653-4574) in group 1 to 2178 mGy (1332-3500; p < 0.001) in group 2 by mainly reducing fluoroscopic contribution by 54.1%, the cineangiographic contribution was lowered by only 6.6%. In group 3 AK dropped drastically to 746 mGy (480-1225; p < 0.001) mainly by reducing the cineangiographic contribution by 53.4%, still there was a further reduction of fluoroscopy contribution of 8.2%. This also led to a reduction of the skin entry dose from 1038 mGy (690-1589) in group 2 to 359 mGy (204-591; p < 0.001) in group 3. This was achieved both in normal weight and obese patients, and both in antegrade and retrograde procedures. CONCLUSIONS: The present study demonstrates that by modifying both the fluoroscopic and cineangiographic contribution to radiation exposure a drastic reduction of radiation risk can be achieved, even in obese patients. Currently accepted radiation thresholds may no longer be a limit for CTO PCI.

Modulated radiation protocol achieves marked reduction of radiation exposure for chronic total coronary occlusion intervention.

OBJECTIVE: To evaluate the feasibility of a new acquisition protocol to reduce radiation exposure. BACKGROUND: Percutaneous coronary interventions (PCI) for chronic total coronary occlusions (CTO) are characterized by the highest radiation exposure among PCI procedures. METHODS: We analyzed 552 consecutive CTO procedures between January 2018 and October 2019. After 366 procedures (Group 1) a modified radiation acquisition protocol was implemented for the subsequent 186 procedures (Group 2). Besides a low fluoroscopy frame rate of 6/s and cine frame rate of 7.5/s for both groups, additional modifications consisted of increased copper filtering with lower entry dose in combination with a modified image postprocessing. Radiation exposure was assessed as air kerma (AK; mGy), and dose-area product (DAP; cGy*cm2 ). RESULTS: There was no significant difference in lesion or procedural complexity between the study groups with 46 and 43% of the procedures done via the retrograde approach. While fluoroscopy time remained similar (median: 32.7 vs. 34.3 min), the protocol modifications resulted in a drastic reduction of AK by 68% from 2,040 (1,321-3,339) mGy to 655 (415-1,113) mGy (p < .001) without affecting the procedural success rate. DAP was equally decreased by 71%. These considerable reductions were observed even in obese patients of BMI > 30. In Group 2, not a single procedure exceeded the 5 Gy threshold as compared to 10.4% in Group 1. CONCLUSIONS: Radiation exposure decreased considerably with a new acquisition protocol without affecting procedure duration and success. These modifications were applicable also to patients with a high BMI.

[Monitoring Radiation Exposure During Surgery with Real Time Measurements: Opportunities and Limitations]. / Überwachung der Strahlenexposition im OP mit Echtzeitmessungen: Möglichkeiten und Grenzen.

BACKGROUND: In Germany, staff exposed to radiation is monitored with official individual dosimeters. Commercially available real-time dosimeters (RTD) can be used as radiation protection dosimeters. They are worn over the apron and display the radiation dose being measured at the desired location at intervals of one second. These real-time radiation exposure measurements enable the surgical staff to take suitable measures to reduce the radiation during the operation. The objective of our study was to monitor the accuracy of the measurements taken from the real-time dosimeter and to determine the radiation scatter for individual members of the surgical staff. MATERIALS AND METHODS: Prospective measurements of the operating team's exposure to radiation were carried out using a real-time dosimeter system in an operating room for vascular surgery equipped with a C-arm. Firstly the calibration of the RTD at the operating table was checked using a water phantom. Subsequently, measurements were taken during vascular interventions and surgery. RESULTS: When calibrated, the values of the individual RTD revealed internal significant deviations, thus a corrective factor was calculated for each RTD. In total 55 interventions on 53 patients were studied. The average dose for the RTD of the surgeon during endovascular aortic repair (n = 11) amounted to 9 ± 9 µSv (range 3.6 - 50 µSv) and during thoracic endovascular aortic repair (n = 6) 35 ± 49 µSv (3.8 - 190.3 µSv). In the case of percutaneous transluminal angioplasty of the pelvis and of the lower extremities (n = 20), the average dose for the RTD of the surgeon was 7 ± 7 µSv (1.2 - 35 µSv) and for the angiographies of the lower extremities (n = 12) at 2 ± 3 µSv (0.2 - 15.9 µSv). The real-time dosimetry provided data which contributed to the operating team changing their behaviour in the operating room. DISCUSSION: Since the dose values determined by the official dosimetry are generally very low, it is not possible to optimise the behaviour and thus the radiation protection using these dose values. This can be achieved with the radiation protection dosimeter and the dose reference levels can be defined in the new Radiation Protection Ordinance (StrlSchV). Instant feedback of the current dose rate at the place where the RTD is worn can lead to both the individual adjusting his or her personal behaviour and to optimisation of the individual's radiation protection. It is only possible to compare the measured data obtained with the RTD when calibration is carried out in advance.