Question 2751
{"accessible":false,"alternatives":[{"id":13428,"text":"getting the anode angle as close to 90 degrees as possible"},{"id":13429,"text":"incident x-ray beam originating from a point source"},{"id":13430,"text":"place the anode side of the beam over the thickest section of tissue"},{"id":13431,"text":"placing the patient as close to the detector as possible"},{"id":13432,"text":"using a focused anti-scatter grid"}],"archived":false,"correctAlternativeId":13429,"explanation":"\u003cp\u003eThe focal spot is responsible for geometric blurring. The greater the effective focal spot size the greater the blurring. This blurring is then amplified by magnification.\u003c/p\u003e\u003cp\u003eReducing magnification reduces blurring but cannot eliminate it. However, if the focal spot was a point source (ie. was infinitely small) there would be no geometric blurring despite any magnification.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eGeometric unsharpness = Effective focal spot * (OID/SOD)\u003c/strong\u003e\u003c/p\u003e","id":2751,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2751","nextQuestionPath":"/articles/grids/questions/2749","relatedArticles":[{"id":29775,"title":"Anode heel effect","link":"/articles/anode-heel-effect?lang=us"},{"id":57546,"title":"Anode angle","link":"/articles/anode-angle?lang=us"},{"id":29771,"title":"Focal spot","link":"/articles/focal-spot?lang=us"},{"id":80077,"title":"Blur","link":"/articles/blur?lang=us"}],"alsoUsedIn":[{"id":1563,"kind":"RestrictedPage","title":"Page 1563 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/1563"},{"id":2007,"kind":"Course","title":"Imaging Physics: X-ray - page 2007","link":"https://radiopaedia.org/courses/imaging-physics-x-ray/pages/2007"},{"id":2007,"kind":"Course","title":"Imaging Physics: X-ray peer review - page 2007","link":"https://radiopaedia.org/courses/imaging-physics-x-ray-peer-review/pages/2007"}],"stem":"\u003cp\u003eWhich of the following would eliminate geometric blurring?\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/2751"}],"attemptsPercentages":[{"alternativeId":"13428","percentage":6},{"alternativeId":"13431","percentage":22},{"alternativeId":"13429","percentage":64},{"alternativeId":"13432","percentage":6},{"alternativeId":"13430","percentage":2}],"promptToLogin":false,"questionManager":false,"articleId":"grids"}