Organ and effective dose reduction in adult chest CT using abdominal lead shielding

Abstract

Objectives: The purpose of this study was to evaluate and compare organ and effective dose savings that could be achieved using conventional lead aprons and a new, custom-designed shield as out-of-plane shielding devices during chest CT scans. Methods: Thermoluminescent dosimeters were used to measure doses throughout the abdomen and pelvis during CT scans of the chest of a RANDO phantom. Dose measurements were made with no shielding, with lead aprons and with the new shield around the abdomen and pelvis in order to quantify the achievable organ and effective dose reductions. Results: Average dose savings in the 10 phantom sections ranged from 5% to 78% with the highest point dose saving of 93% being found in the mid-pelvis. When shielding was used, the maximum measured organ dose reduction was a 72% dose saving to the testes. Significant dose savings were found throughout the abdomen and pelvis, which contributed to an effective dose saving of 4% that was achieved over and above the dose savings obtained through conventional optimisation strategies. This could yield significant population dose savings and reductions in collective radiation risk. Conclusion: In this study significant organ and effective dose reductions have been achieved through the use of abdominal shielding during chest CT examinations and it is therefore recommended that out-of-plane patient shielding devices should be used for all chest CT scans and potentially for every CT scan, irrespective of body part.

Effectiveness of abdominal shields in chest radiography: a Monte Carlo evaluation

“…There was a measurable (absolute) dose reduction in regions within the phantom, outside the primary beam, with the use of the abdominal shield (Figure 2), which was greatest near the edge of the X-ray field and closer to the surface. In relative terms, however, the dose reduction increases as the distance from the primary beam edge increases and the depth in the phantom decreases ( Figure 3)-which is in agreement with the results of a previous phantom study that investigated the effectiveness of an abdominal shield used during chest CT. 9 The dose reduction to the phantom voxels protected with the shield was very small and did not exceed 0.09 mGy for voxels at 4 cm or deeper from the phantom surface. In a voxel at a depth of 8 cm and at 15 cm from X-ray field (corresponding approximately to the level of the uterus and ovaries), the dose reduction was about 0.035 mGy or approximately 4% of the dose value in that voxel when the abdominal shield was not used (Figures 2 and 3).…”

“…5,6 A similar practice, often referred to as "out-of-plane" shielding, has also found an application in dental radiography and CT, where there were reports of a noticeable dose reduction to shielded organs. [7][8][9] During chest X-ray examinations, the use of abdominal shields complicates and possibly compromises the procedure, and their role in reducing patient dose is controversial. While Njeh et al 6 found a negligible radiation protection effect from the use of abdominal shields during chest X-ray examinations, Hashimoto et al 10 and Jackson et al 11 reported a significant level of dose reduction.…”

The use of out-of-plane high Z patient shielding for fetal dose reduction in computed tomography: Literature review and comparison with Monte-Carlo calculations of an alternative optimisation technique

“…We found 11 relevant articles, listed in Table 1 [3,[11][12][13][14][15][16][17][18][19][20]. All of them reported uterus exposure due to CT imaging performed for exclusion of pulmonary embolism (PE).…”

Praktischer Strahlenschutz am Patienten in der radiologischen Diagnostik

“…30 % (Reduktion der Organdosis um 23 μSv) [7,18]. Eine vergleichbare Reduktion der anderen Bauchorgane (z.…”