X rays are a type of radiation used in imaging and therapy that uses short wavelength energy beams capable of penetrating most substances except heavy metals.
Diagnostic x rays are some of the most powerful medical imaging tools available. Other imaging techniques that do not use x rays include magnetic resonance imaging (MRI), ultrasonography, and radio nucleotide imaging. Based on the symptoms presented by the patient, the physician can request specific x rays (such as chest x rays) that help diagnose many types of cancers, including sarcomas, lymphomas, and lung cancers. X rays allow the physician to visualize certain internal body conditions with little or no invasive procedures. Conditions may be visualized on photographic film, or for more complex and detailed information, computed tomography (CT scan), fluoroscopy, or angiography might be used.
Before consenting to any x-ray procedure, the patient should consider the impact of existing medical conditions or medications. Sensitivities to contrast dyes may produce allergic reactions. Pregnant women or those who suspect they might be pregnant should consult a physician prior to x-ray treatments to avoid injury to the fetus. Nursing mothers may be required to store enough milk to last for 48 hours following certain procedures. Patient age should always be taken into consideration when choosing the type and intensity of x ray. Patients should be aware that some prescribed cancer medications act as radio sensitizers and amplify the effect of x rays. Any patient with a suppressed immune system or diabetes may require special x-ray procedures.
X-ray procedures are administered in a hospital or clinical setting. Most procedures may be conducted on an outpatient basis. The time required for the procedure may vary from a few minutes to more than an hour. There is little or no discomfort associated with diagnostic x rays. The general procedure for diagnostic x rays include:
• proper positioning and shielding of the patient
• administering contrast dyes, if necessary
• administering radiation
• review of the films by a technician to insure proper imaging
• Scheduling a time to review the films with the radiologist. However, if fluoroscopy or angiography is used, the procedure is dynamic (in motion), and the radiologist is present during the x ray administration.
• dismissal of the patient
Diagnostic x rays require little preparation. The patient may be required to abstain from food and liquids for a certain period prior to the x ray. For some x rays, enemas may be necessary or a contrast agent may be administered immediately prior to or during the procedure.
For non-invasive diagnostic x-ray procedures, the patient is dismissed immediately after the films have been reviewed, and little or no aftercare is necessary.
A general rule for x rays suggests that the beneficial effects of x rays far exceed the risks involved. As a result of certified training and strict guideline compliance, risks from technical application are essentially nonexistent. However, for any x-ray procedure, radiation exposure is always a concern, and although uncommon, the risk of infection during invasive techniques can not be discounted.
Diagnostic x rays provide detailed information that the physician can use to determine the best approach to correct or control a medical problem. Normal results would indicate no existing abnormalities.
Abnormal results would indicate irregularities such as a tumor, an enlarged lymph node, or pleural effusion. Although highly unlikely, diagnostic x-ray films can be misread and the wrong diagnosis made.
Brant, William E., and Clyde A. Helms, editors. Fundamentals of Diagnostic Radiology. 2nd ed. Baltimore: Williams & Wilkins, 1999.
Henchke, Claudia, et al. "Early Lung Cancer Action Project: Overall Design and Findings from Baseline Screening." Lancet 354 (July 1999): 99–105.
"CT Screening Detects Majority of Lung Cancer Cases Missed by X ray." RSNA Meeting. Dec., 1998. [cited March 29, 2001 and June 28, 2001]. .
Harrison, Pam. Lung Cancer Detected Earlier with CT Scan than with X ray. 2000 Reuters Ltd. 29 March 2001. [cited June 28, 2001]. .
Marchant, Joan. "Pixels Join Cancer Fight." The Guardian. Dec. 1999. [cited April 21, 2001 and June 28, 2001].
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التعديل الأخير تم بواسطة جوهرة المحيط ; 2007-05-29 الساعة 06:00 PM