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radiation protection in fluoroscopy

OverviewPhysicians performing fluoroscopically guided procedures should be aware of the potential for serious radiation-induced skin injury. Occasionally this is an unavoidable consequence of the time required to perform complex procedures. Some of this, however, can be minimized through a better understanding of how the equipment works and how some operational procedures affect the total skin dose. Following is a summary of desirable techniques to optimize C-Arm use and reduce dose to pati9453

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radiation protection in fluoroscopy

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    1. Radiation Protectionin Fluoroscopy

    13. Exposure Limits General public: TEDE ? 100 mrem/yr Dose in unrestricted area: ? 2 mrem in 1 hr Patients (diagnostic, therapy): no limits Occupational Users: - Maximum Permissible Dose - ALARA goals: 10% of MPDs (As Low As Reasonably Achievable) - Lifetime TEDE in rem < Age

    14. Exposure Limits MPD ALARA (mrem/yr) Whole Body 5,000 500 (head,trunk, arms above elbows, legs above knees) Extremeties 50,000 5,000 (arms below elbow, legs below knee) Individual organs; skin 50,000 5,000 Lens of the eye 15,000 1,500 Embryo / Fetus: 500 mrem over 9 months; ? 50 mrem/month

    16. X-ray Tube Position Position the X-ray tube under the patient not above the patient. The largest amount of scatter radiation is produced where the x-ray beam enters the patient. By positioning the x-ray tube below the patient, you decrease the amount of scatter radiation that reaches your upper body.

    17. Collimation Collimate tightly to the area of interest. Reduces the patient’s total entrance skin exposure. Improves image contrast. Scatter radiation to the operator will also decrease.

    19. Protection of Personnel (2) TIME - Take foot off fluoro pedal if physician is not viewing the TV monitor - Use last image hold (freeze frame) - Five-minute timer - Use pulsed fluoro instead of continuous fluoro 1 pps: 5% dose with respect to continuous fluoro 2 pps: 10% 4 pps: 20% - Low-Dose mode: 40% dose of Normal fluoro - Pulsed Low-Dose provides further reduction with respect to Normal-- - Dose continuous mode: 1 pps = 2% of dose; 2 pps = 4%; 4 pps = 8%; 8 pps = 15% - Use record mode only when a permanent record is required - Record beam-on time for review

    20. Protection of Personnel (3) DISTANCE - One step back from tableside: cuts exposure by factor of 4 - Lateral fluoroscopy: 5x less dose on Image Int. side - Move Image Int. close to patient: less patient skin exposure less scatter (more dose interception by tower) sharper image - Source to Skin Distance (SSD): 38 cm for stationary fluoroscopes 30 cm for mobile fluoroscopes

    21. Protection of Personnel (4) SHIELDING - Lead aprons: cut exposure by factor of 20 distant scatter: 0.25 mm Pb eq direct involvement: 0.5 mm Pb eq Proper storage (hanging vs. folding) - Thyroid collars; eye glasses; wrap around aprons - Properly used ceiling mounted shields - Use shielded rooms - Patient shielding: thyroid, eyes, gonads

    27. Notable Changes: FDA regs. For equipment manufactured after 10 June 2006: Warning Label – “WARNING: This x-ray unit may be dangerous to patient and operator unless safe exposure factors, operating instructions and maintenance scheduled are observed.” Timer: audible signal every 5 min of irradiation time until reset AND Irradiation time display at fluoroscopist’s working position: - means to reset display at zero for new exam/procedure Last Image Hold (LIH) after exposure termination - indicate if LIH = radiograph or ‘freeze-frame’ image

    28. AKR and Cumulative AK display: - dose at the point of entrance of beam into patient - continuously at fluoroscopist’s working position - AKR (mGy/min, mGy/sec, ?Gy/sec) - CAK (mGy) - both displays must be distinguishable - means to reset for new exam / procedure - accuracy: +35% of actual values Dose Area Product (DAP) displays: - applicable to European regs., not US FDA regs. - dose x area at skin - mGycm2, ?Gycm2, radcm2 - Accuracy: +50%

    29. Notable Changes: State regs. Fluoroscopy Operators All non-radiologist physician operators must be trained and granted privileges to perform fluoroscopy. Written policies and procedures for restricting the use of fluoro equipment only to those physicians who have been granted privileges must be in force. Non radiologists using fluoro equipment: annual training is required.

    30. Patient Dose Evaluation For each fluoro machine, maintain a log of each use containing: Patient ID, type of exam, date of exam, fluoro time, number of spot films, and operators name If fluoro times indicate possibility that skin entry dose may have exceeded 100 Rads, procedure must be reviewed in detail to determine max skin entry dose. Review includes patient description, part of anatomy involved, max fluoro time on any specific area, percentage of mag views, spot films, dose levels delivered. If skin entry dose exceeds 100 Rad, note in patient record, notify RSC

    31. Online Competency Quiz

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