The impact of anthropometric patient-phantom matching on organ dose: A hybrid phantom study for fluoroscopy guided interventions
Patient standing height versus weight shown for patient-dependent and patient-specific (a) male and (b) female phantoms.
Patient-dependent (P-d) phantoms were modified to match the contoured patient-specific (P-s) datasets. Modification included the removal of cartilage, intestines, and prostate among others, and the rotation of the scapulae to mimic an arms-raised positioning. The increased lung volume of the patient-specific phantoms due to breath-holding techniques is also highlighted.
Patient-phantom matching by height and weight where the closest patient-dependent phantom is shown for three different adult male patients. [(a) and (b), large] Patient-dependent 90th percentile by height/90th percentile by weight, 182.9 cm/110.0 kg—Patient-specific 182.9 cm/112.7 kg. [(c) and (d), medium] Patient-dependent 75th/50th, 178.3 cm/82.3 kg—Patient-specific 175.2 cm/80.9 kg. [(e) and (f), small] Patient-dependent 10th/10th, 163.7 cm/57.6 kg—Patient-specific 157.5 cm/43.6 kg.
Improved accuracy with increasing kVp. Shown for RAO projections as the average of all organs for all male patients.
(a) Improved accuracy for heavy patients, but no improvement for light patients. Shown for 80 kVp RAO, LPO, left lateral, and PA projections as the average of all organs for all male patients. (b) Improved accuracy for heavy patients, but no improvement for light patients. Shown for 80 kVp RAO, LPO, left lateral, and PA projections as the average of all organs for all female patients.
(a) Percent difference for each of the five heavy male patients as matched to a reference hybrid phantom, matched by height to a patient-dependent phantom, and matched by height and weight to a patient-dependent phantom. Each phantom was also matched using a patient-specific contour but using patient-dependent organs. (b) Four different matching techniques as highlighted in (a).
Improved accuracy with increasing field of view, shown as the average of all and primary organs for two male patients.
Mean organ volumes as contoured from 14 male and 13 female CT datasets. Reference organ volumes are also listed for the 50th percentile by weight/50th percentile by mass UFHADM and UFHADF and for the reference stylized model.
Mean absolute percent difference for individual organs of three patient groupings, all (14 patients), heavy (5), and light (9) male patients as calculated for 80, 100, and 120 kVp RAO projections. Primary organs for RAO projects were considered to be the pericardium, stomach, pancreas, and liver.
Percentage point improvement over a reference hybrid phantom. Primary organs were those which received the highest dose in each projection.
Percentage point improvement over a reference stylized phantom. Primary organs were those which received the highest dose in each projection.
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