Fluoroscopy

Whereas scintillation screens can be used to directly view x-rays passing through the body, the dose to a patient is too high. Instead, scintillation screens are combined with video cameras or electronic intensifier tubes and video cameras. This detection scheme is used in digital radiography where digital x-ray images are recorded, and fluoroscopy where temporal processes are to be followed. 

Placement of vascular access ports is similar to that of a long-term indwelling arterial catheter. A small incision is made over the selected vein and a second incision is made lower in the anterior chest to create a pocket to house the port. The catheter is tuimeled subcutaneously from its entry point into the vein with the tip inside the right atrium. The final position of the catheter is verified by fluoroscopy, secured with sutures, and the subcutaneous pocket is closed. The port septum is easily palpable transcutaneously, and the system may be used immediately. A surgeon typically inserts the vascular access port in an outpatient setting. 

X-ray fluoroscopy is used for direct on-line examination. A fluorescent screen is used to convert x-ray photons into visible light photons. A television camera receives the visible image and displays it on a television screen (see Fig. 19). This type of system is used for security screening of carry-on luggage at airports. 

Fluoroscopy is the visual examination of X-ray shadow images by means of a fluorescent screen. It may be used for the inspection of light mcCul CuStings soi s sinmiifiition castings of explosives etc. In this method, the images are formed directly on a screen and no films are required, which makes the cost of inspection lower than with ordinary X-ray examination Refs 1) Hackh s (1944), 349... 

Specific Approach When Protective Aprons Are Worn During Diagnostic and Interventional Medical Procedures Using Fluoroscopy... 

Clinical staff taking part in diagnostic and interventional procedures using fluoroscopy wear protective aprons to shield internal tissues and organs in the torso from scattered x rays. Use of the measurements from monitoring devices worn outside and above protective aprons as the record of or E for these individuals results in significant overestimates of their actual risk. 

Other uses of fluoroscopy would have the potential for higher cumulative collar exposures. For example, abdominal interventional and angiography procedures typically use image intensifiers and x-ray field sizes which are larger than those used in a cardiac catheterization laboratory. Depending on the orientation of the primary beam, the scattered radiation from the patient may have greater intensity in these other clinical situations than in a cardiac catheterization laboratory. 

Extensive experimental measurements have been performed that simulate the irradiation of clinical staff for conditions commonly encountered in fluoroscopy (Faulkner and Harrison, 1988 Faulkner and Marshall, 1993). 

The conversions between H, or E and Hp(10) for the film badges worn under the apron at the waist are quite variable with kVp. The fluctuations in kVp used during various fluoroscopy procedures render a direct application of these conversions for individual workers impractical. The conversions between He or E and. HpdO) for the film badges worn outside and above the apron at the neck are less variable with kVp, differing by less than a factor of 3 for He and less than a factor of 3.4 for E. 

ROSENSTEIN, M. and WEBSTER, E.W. (1994). Effective dose to personnel wearing protective aprons during fluoroscopy and interventional radiology, Health Phys. 67, 88-89. 

BOICE, J.D., Jr. (1979). Multiple chest fluoroscopies and the risk of breast cancer, page 147 in Advances in Medical Oncology Research, and Education, VoL 1, Margison, G.E, Ed. (Pergamon Press, New %rk). 

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