Question 752
{"accessible":false,"alternatives":[{"id":3850,"text":"the mA decreases and patient entrance skin dose is constant"},{"id":3814,"text":"the mA decreases and patient entrance skin dose decreases"},{"id":3815,"text":"the mA decreases and patient entrance skin dose increases"},{"id":3817,"text":"the mA increases and patient entrance skin dose is constant"},{"id":3818,"text":"the mA increases and patient entrance skin dose decreases"},{"id":3816,"text":"the mA increases and patient entrance skin dose increases"}],"archived":false,"correctAlternativeId":3816,"explanation":"\u003cp\u003eAutomatic brightness control\u0026nbsp;is used to keep the brightness of the displayed image at a constant level during examinations. It involves the adjustment of the kV and mA automatically depending on the part of the anatomy being examined. To keep brightness constant as kV is decreased, mA has to increase to compensate, thereby increasing the rate of photon emission and increasing the skin dose.\u003c/p\u003e\u003cp\u003eAdapted from\u0026nbsp;\u003ca href=\"https://en.wikibooks.org/wiki/Basic_Physics_of_Digital_Radiography\"\u003eBasic Physics of Digital Radiography\u003c/a\u003e\u0026nbsp;by\u0026nbsp;Kieran Maher,\u0026nbsp;with author's permission (License:\u0026nbsp;\u003ca href=\"https://creativecommons.org/licenses/by-sa/3.0/\"\u003eCreative Commons\u0026nbsp;BY-SA 3.0\u003c/a\u003e).\u003c/p\u003e","id":752,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/803","nextQuestionPath":"/articles/kilovoltage-peak/questions/654","relatedArticles":[],"alsoUsedIn":[],"stem":"\u003cp\u003eA fluoroscopic system has automatic brightness control in which the kV is adjusted manually and the mA varies as a function of patient thickness. For a given patient thickness, as the kV is decreased...\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/752"}],"attemptsPercentages":[{"alternativeId":"3817","percentage":27},{"alternativeId":"3818","percentage":12},{"alternativeId":"3814","percentage":11},{"alternativeId":"3850","percentage":3},{"alternativeId":"3816","percentage":42},{"alternativeId":"3815","percentage":6}],"promptToLogin":false,"questionManager":false,"articleId":"kilovoltage-peak"}