A Photographic Method of Measuring Fluoroscopic Dose to the Patient

Blatz, Hanson; Epp, Edward R.

doi:10.1148/76.1.120

Cited by 8 publications

(1 citation statement)

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“…Several authors have described the use of film to measure skin dose. [8][9][10][11][12] However most photographic films are too sensitive at diagnostic x-ray energies for use as dosimeters in interventional procedures 13 and accuracy is limited to about 20-25%. Since interventional procedures often require repositioning of the x-ray source relative to the patient, it is not possible to predict where the maximum skin dose will occur.…”

Section: Introductionmentioning

confidence: 99%

Suitability of laser stimulated TLD arrays as patient dose monitors in high dose x‐ray imaging

et al. 1997

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Skin entrance doses of patients undergoing interventional x-ray procedures are capable of causing skin damage and should be monitored routinely. Single TLD chips are not suitable because the location of maximum skin exposure cannot be predicted. Most photographic films are too sensitive at diagnostic x-ray energies for dosimetry, exhibit temporal changes in response, and require special packaging by the user. We have investigated the suitability of laser heated MgB4O7 TLDs in a polyimide binder in the range of 0.2-20 Gy. These are available in radioluscent arrays up to 30 x 30 cm for direct measurement of patient skin dose. Dose response was compared with a calibrated ion chamber dosimeter. Exposures were made at 60, 90, and 120 kVp, at low (fluoroscopy) and high (DSA) dose rates, and at different beam incidence angles. Longitudinal reproducibility and response to temperature changes during exposure were also checked. The dose response is linear below approximately 6 Gy where the slope starts to increase 2% per Gy. Errors were less than +/- 2% over a 0-80 degrees range of beam incidence angles; less than +/- 3% for both dose rate variations and kVp differences between 70 and 120 kVp. The response was unaffected by temperature changes between 20 and 37 degrees C. Reproducibility is current +/- 7%. MgB4O7 TLD arrays are suitable for patient dosimetry in high dose fluoroscopy procedures if appropriate calibrations are used. Uncertainty in skin dose measurement is less than 10%, which is substantially better than film dosimetry.

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