Radiación ionizante secundaria generada en equipos de cineangiografía coronaria digital y analógica: influencia de los sistemas externos de protección radiológica / Secondary ionizing radiation generated by analog and digital coronary cineangiographic equipment: influence of external protection devices

Background: Exposure to ionizing radiation is a known hazard of radiological procedures. Aim: To compare the emission of secondary ionizing radiation from two coronary angiographic equipments, one with digital and the other with analog image generation. To evaluate the effectiveness of external radiological protection devices. Material and methods: Environmental and fluoroscopy generated radiation in the cephalic region of the patient was measured during diagnostic coronary angiographies. Ionizing radiation generated in anterior left oblique projection (ALO) and in anterior right oblique projection (ARO) were measured with and without leaded protections. In 19 patients (group 1), a digital equipment was used and in 21 (group 2), an analog equipment. Results: Header radiation for groups 1 and 2 was 1194 ñ 337 and 364 ñ 222 µGray/h respectively (p<0.001). During fluoroscopy and with leaded protection generated radiation for groups 1 and 2 was 612 ñ 947 and 70 ñ 61 µGray/h respectively (p<0.001). For ALO projection, generated radiation for groups 1 and 2 was 105 ñ 47 and 71 ñ 192 µGray/h respectively (p<0.001). During filming the radiation for ALO projection for groups 1 and 2 was 7252 ñ 9569 and 1671 ñ 2038 µGray/h respectively (p = 0.03). Out of the protection zone, registered radiation during fluoroscopy for groups 1 and 2 was 2800 ñ 1741 and 1318 ñ 954 µGray/h respectively (p < 0.001); during filming, the figures were 15500 ñ 5840 and 18961 ñ 10599 µGray/h respectively (NS). Conclusions: Digital radiological equipment has a lower level of ionizing radiation emission than the analog equipment

Mechanisms of coronary hyperconstriction in response to serotonin induced by X-irradiation in miniature pigs: increased constrictive response of medial smooth muscle.

Experimental and clinical studies suggest that X-irradiation to the coronary artery may enhance vasoconstrictive response. This study aimed to clarify the effect of X-irradiation on the vasomotor response of porcine coronary artery. X-ray (15 Gy) was selectively irradiated to the left anterior descending coronary artery (LAD) in 14 Göttingen miniature pigs. The coronary vasomotor responses to serotonin at the irradiated site (LAD) and the control site (the left circumflex artery; LCX) were assessed by quantitative arteriography before and 1 h and 1, 2, and 4 weeks after X-irradiation. At 2 weeks, endothelium-dependent vasodilation in response to substance P was also evaluated arteriographically in vivo. At 2 weeks, isometric tension studies were performed to evaluate the constrictive responses of medial muscle strips and endothelium-dependent relaxation. Coronary vasoconstriction in response to serotonin was enhanced 1 week after, and further augmentation was noted 2 and 4 weeks after X-irradiation. Endothelium-dependent vasodilation in response to substance P in vivo was preserved 2 weeks after X-irradiation. Coronary arteriography showed no organic stenosis at the irradiated site. In vitro studies demonstrated that medial muscle strips of the irradiated site showed hypercontraction in response to serotonin and that endothelium-dependent relaxation in response to serotonin and substance P was preserved at the irradiated site. A histological study revealed no appreciable changes of the endothelial cells or intimal thickening.(ABSTRACT TRUNCATED AT 250 WORDS)