[Study on the development of a patient dosimetry gown for interventional cardiology procedures].

In recent years, dose justification and optimization have been attempted in percutaneous coronary intervention (PCI); however, deterministic effects have been reported. To prevent radiation skin injuries in PCI, it is necessary to measure the patient entrance skin dose (ESD), but an accurate dose measurement method has not yet been established. In this study, we developed a dosimetry gown that can measure the ESD during PCI using multiple radiophotoluminescence dosimeters (RPLDs). The RPLDs were placed into 84 pockets that were sewn into a dosimetry gown. Patients wear the original dosimetry gown during the procedures, after which we obtain accurate ESD measurements. We believe that this method using RPLDs and a newly-designed dosimetry gown provides accurate ESD measurements during PCI. We expect this system to become a standard method for measuring ESD during PCI.

Fundamental study on the characteristics of a radiophotoluminescence glass dosemeter with no energy compensation filter for measuring patient entrance doses in cardiac interventional procedures.

Cardiac interventional procedures have been increasing year by year. However, radiation skin injuries have been still reported. There is a necessity to measure the patient entrance skin dose (ESD), but an accurate dose measurement method has not been established. To measure the ESD, a lot of radiophotoluminescence dosemeters (RPLDs) provide an accurate measurement of the direct actual ESD at the points they are arrayed. The purpose of this study was to examine the characteristics of RPLD to measure the ESD. As a result, X-ray permeable RPLD (with no tin filter) did not interfere with the percutaneous coronary intervention procedure. The RPLD also had good fundamental performance characteristics. Although the RPLD had a little energy dependence, it showed excellent dose and dose-rate linearity, and good angular dependence. In conclusion, by calibrating the energy dependence, RPLDs are useful dosemeter to measure the ESD in cardiac intervention.

The necessity of follow-up for radiation skin injuries in patients after percutaneous coronary interventions: radiation skin injuries will often be overlooked clinically.

BACKGROUND: Percutaneous coronary intervention (PCI) offers great benefit that could improve a patient's quality of life. However, numerous case reports of patient radiation injury resulting from PCI are being published, these reports likely represent a small fraction of the actual cases. PURPOSE: To demonstrate the appropriate duration of patient follow-up after PCI to identify radiation effects. MATERIAL AND METHODS: We evaluated 400 consecutive PCIs. The radiation dose (dose-area product, cumulative dose, maximum skin dose), number of cine runs, and fluoroscopic time were recorded for all patients. The skin on the patients' backs was reviewed periodically after PCI. RESULTS: Radiation skin effects occurred in six patients from PCI of the right coronary artery in chronic total occlusion (CTO) patients (mild erythema; occurrence rate 1.5%). Skin injury in two patients appeared in cycles. In most cases, erythema was vividly seen at 4 weeks after PCI. CONCLUSION: Careful observation for skin injury is needed. At a few days following PCI, early erythema can be detected through careful observation by well-trained staff. At 7-10 days after PCI, most erythematous pigmentation can be detected. At 4 weeks after PCI, most skin erythema appears clearly, however, some cases of skin erythema occur without back pain. After that, follow-up every 6 months is needed to detect the reappearance of erythema.

[Reduction method of patients' radiation dose considering the size of field of view with a digital cine X-ray system loading a flat-panel detector].

Angiographic equipment has tended toward using flat-panel detector (FPD). However, the radiation dose varies depending on the size of field of view (FOV) in the FPD. Although we were using 7 inch FOV in cardiac procedures, we examined a way to reduce the patients' radiation dose by using 8 inch FOV utilizing a digital zoom processing. We measured the absorbed dose rates at an interventional reference point (IRP) with 20 cm acrylic board to compare 8 inch FOV using a digital zoom processing with 7 inch FOV. Additionally we visually evaluated these phantom images. Result of comparison of absorbed dose rates at IRP, 8 inch FOV using a digital zoom processing was reduced more than 7 inch FOV (fluoroscopic 29.0% and digital cine 37.5%). These phantom images were of equivalent quality. The method to use 8 inch FOV utilizing a digital zoom processing technique in cardiac procedures is one of the effective radiation exposure reduction methods.

Evaluating the maximum patient radiation dose in cardiac interventional procedures.

Many of the X-ray systems that are used for cardiac interventional radiology provide no way to evaluate the patient maximum skin dose (MSD). The authors report a new method for evaluating the MSD by using the cumulative patient entrance skin dose (ESD), which includes a back-scatter factor and the number of cineangiography frames during percutaneous coronary intervention (PCI). Four hundred consecutive PCI patients (315 men and 85 women) were studied. The correlation between the cumulative ESD and number of cineangiography frames was investigated. The irradiation and overlapping fields were verified using dose-mapping software. A good correlation was found between the cumulative ESD and the number of cineangiography frames. The MSD could be estimated using the proportion of cineangiography frames used for the main angle of view relative to the total number of cineangiography frames and multiplying this by the cumulative ESD. The average MSD (3.0 ± 1.9 Gy) was lower than the average cumulative ESD (4.6 ± 2.6 Gy). This method is an easy way to estimate the MSD during PCI.