Estimating head and neck tissue dose from x-ray scatter to physicians performing x-ray guided cardiovascular procedures: a phantom study

Abstract

Physicians performing x-ray guided interventional procedures have a keen interest in radiation safety. Radiation dose to tissues and organs of the head and neck are of particular interest because they are not routinely protected by wearable radiation safety devices. This study was conducted to facilitate estimation of radiation dose to tissues of the head and neck of interventional physicians based on the dose recorded by a personal dosimeter worn on the left collar. Scatter beam qualities maximum energy and HVL were measured for 40 scatter beams emitting from an anthropomorphic patient phantom. Variables of the scatter beams included scatter angle (35° and 90°), primary beam peak tube potential (60, 80, 100, and 120 kVp), and 5 Cu spectral filter thicknesses (0-0.9 mm). Four reference scatter beam qualities were selected to represent the range of scatter beams realized in a typical practice. A general radiographic x-ray tube was tuned to produce scatter-equivalent radiographic beams and used to simultaneously expose the head and neck of an anthropomorphic operator phantom and radiochromic film. The geometric relationship between the x-ray source of the scatter-equivalent beams and the operator phantom was set to mimic that between a patient and physician performing an invasive cardiovascular procedure. Dose to the exterior surface of the operator phantom was measured with both 3 × 3 cm pieces of film and personal dosimeters positioned at the location of the left collar. All films were scanned with a calibrated flatbed scanner, which converted the film's reflective density to dose. Films from the transverse planes of the operator phantom provided 2D maps of the dose distribution within the phantom. These dose maps were normalized by the dose at the left collar, providing 2D percent of left collar dose (LCD) maps. The percent LCD maps were overlain with bony anatomy CT images of the operator phantom and estimates of percent LCD to the left, right and whole brain, brain stem, lenses of the eyes, and carotid arteries were calculated. Per expectation, results indicated greater percent dose to superficial versus deep tissues and increasing percent dose to deep tissues with increasing scatter-equivalent beam energy and HVL. The results enable estimation of the scatter dose to tissues of the head and neck of interventional physicians based on occupational dose measured by a personal dosimeter worn at the collar outside the protective apron.

Occupational doses to the eye lens in pediatric and adult noncardiac interventional radiology procedures

“…As expected, higher conversion factors were found for the left eye which is closer to the scatter source. In particular, the collar-to-lens conversion factors found for the left eye (56%-82%) are similar to those obtained by Fetterly et al 23 on a phantom-based study (59%-72%). However, regarding the right eye, considerably higher values were found (49%-54%) compared to those reported by Fetterly et al 23 (22%-27%).…”

“…In particular, the collar-to-lens conversion factors found for the left eye (56%-82%) are similar to those obtained by Fetterly et al 23 on a phantom-based study (59%-72%). However, regarding the right eye, considerably higher values were found (49%-54%) compared to those reported by Fetterly et al 23 (22%-27%). This difference could be due to the angular position of the radiologists, who might need to be rotated toward the tube under real clinical conditions.…”

“…5 The majority of the studies conducted to assess occupational lens exposure in interventional rooms focus on interventional cardiology, [11][12][13][14][15][16][17][18] do not distinguish among specialties, 19,20 or were performed with phantoms. 7,8,[21][22][23] Few studies have been performed regarding adult noncardiac IR. Some analyzed only a limited number of procedures 24,25 or estimated the lens dose from a dosimeter placed at the chest level.…”

“…The majority of the studies conducted to assess occupational lens exposure in interventional rooms focus on interventional cardiology, 11–18 do not distinguish among specialties, 19,20 or were performed with phantoms 7,8,21–23 . Few studies have been performed regarding adult noncardiac IR.…”

Modified design of x‐ray protective clothing to enhance radiation protection for interventional radiologists

“…[7][8][9][10] For the operator in the position described above, incoming scatter radiation is not uniform and mainly incident from the left-anterior direction. 3,11,12 The standard designs of widely used x-ray protective clothing are the apron and wrap-around types. [13][14][15] The apron type provides protection mainly at the anterior area of the wearer and partly at the side areas.…”