Investigation into the effects of lead shielding for fetal dose reduction in CT pulmonary angiography

Kennedy, Erika; Iball, Gareth; Brettle, D S

doi:10.1259/bjr/31771954

Cited by 49 publications

(39 citation statements)

References 20 publications

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“…The most radiosensitive organ fully in the protected area, according to ICRP 103 [23], is the colon, which has a tissue weighting factor of 0.12; the measured dose reduction to the colon was 33.2%. The reduction in the dose to the uterus with the new shield in place was 35.4% and was 42.1% with the conventional aprons; this agrees well with the value of 39.7% found by Kennedy et al [13] using a Siemens Sensation 16 scanner.…”

Section: Dose Savings Per Phantom Sectionsupporting

confidence: 89%

“…In recent years a number of papers have shown that abdominal shielding yields foetal dose reductions of approximately 35% in both early and late stage pregnancy when patients undergo chest CT [13][14][15]. Despite this evidence, out-of-plane shielding has not been used regularly in CT scanning even though the use of such shielding has no effect on the quality of the images produced.…”

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confidence: 99%

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

Iball¹,

Brettle²

2011

BJR

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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.

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Section: Dose Savings Per Phantom Sectionsupporting

confidence: 89%

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confidence: 99%

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

Iball¹,

Brettle²

2011

BJR

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“…The use of a lead apron/shield to cover the abdomen during CTPA has been shown to moderately reduce the leakage and scattered radiation to the uterus from the CT collimators. 33 We found that maternal breast dose is generally higher for CTPA than for VQ, but organ-based tube current modulation has been shown to reduce this. 35 Further opportunities to reduce CTPA radiation doses include the use of statistical and model-based iterative reconstruction techniques, 36 reducing the tube voltage, as we have already performed from 120 to 100 kVp, 37 increasing the pitch to above 1 and decreasing the scan volume.…”

Section: Dosimetrymentioning

confidence: 74%

“…The relevant quantity for planning the exposure of patients and risk-benefit assessments is the equivalent dose or the absorbed dose to irradiated tissues. 33 Readers may wish to refer to a general discussion on the typical errors associated with the application of effective dose to medical exposures, 34 which reports a relative uncertainty of about 640% for a reference patient and still higher for this study, where we have attempted to report the dose to individuals. Similar limitations apply to dose calculations for radiopharmaceuticals.…”

Section: Dosimetrymentioning

confidence: 99%

Diagnosing venous thromboembolism in pregnancy

Grüning

Mingo

Gosling

et al. 2016

BJR

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Objective: We report the imaging outcomes of all pregnant patients referred for suspected thromboembolism over a 43-month period. Methods: We identified 168 patients who underwent ventilation/perfusion (VQ) single-photon emission CT (SPECT), CT pulmonary angiography (CTPA) or a Doppler ultrasound scan of the lower legs, as well as a control group of 89 non-pregnant age-and sex-matched patients who underwent VQ SPECT during the same period. Imaging outcomes were recorded, and radiation doses were calculated for individual patients. Results: VQ SPECT and CTPA were equally likely to diagnose pulmonary embolism (PE) in about one patient out of every seven patients investigated. One in three CTPA scans was of suboptimal quality. A Doppler ultrasound examination of the legs will find deep venous thrombosis much less often, in about 1 patient out of every 15 patients investigated. The prevalence of PE in pregnant patients (as diagnosed by VQ SPECT) was similar to that in the non-pregnant, age-and sex-matched control group. The effective dose and the absorbed radiation dose to the maternal breast were lower with VQ SPECT. The foetal dose is comparable for both VQ SPECT and CTPA. Conclusion: VQ SPECT and CTPA provide a similar diagnostic yield for diagnosing PE during pregnancy, but VQ SPECT does so with a lower radiation dose to the mother (effective dose and breast dose). Advances in knowledge: Ours is the first report of the diagnostic performance of VQ SPECT, rather than planar VQ scans, in pregnancy in a routine clinical setting.

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“…25,32 The radiation risk for the foetus is less than with a VQ scan. 23 Exposure of the foetus can be reduced by 43 using a lead apron with a thickness of 0.7 mm that covers the patient. A lesser thickness can be used over the back of the patient, maximising the distance between the edge of the scan and the foetus.…”

Section: Diagnosismentioning

confidence: 99%

Managing acute collapse in pregnant women

Lombaard

Soma-Pillay

Farrell

2009

Best Practice & Research Clinical Obstetrics & Gynaecol

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Keywords:acute collapse pulmonary embolism amniotic fluid embolism acute coronary syndrome mechanical prosthetic heart valves acute aortic dissection cerebrovascular incidents and anaesthetic complications failed intubation anaphylaxisThe most important causes of acute collapse in pregnancy are pulmonary embolism, amniotic fluid embolism, acute coronary syndrome, thrombosed mechanical prosthetic heart valves, acute aortic dissection, cerebrovascular incidents and anaesthetic complications like failed intubation, anaphylaxis, and problems relating to regional or local anaesthetic agents. The management is based on supporting the different organ systems that are affected. The diagnosis of pulmonary embolism is based on a clinical suspicion supported by certain diagnostic test. Tests like D-dimers have their limitations and cannot be used alone to exclude the diagnosis especially when there is a high clinical suspicion. The choice of the best diagnostic tool is based upon weighing longterm risks to both mother and foetus on the one side and delaying the diagnosis on the other side. The management of acute coronary syndrome is based on immediate angiography and percutaneous coronary intervention. Although there are reports of the use of clopidrogel in pregnancy, there are few data on its effect on the foetus. There is no clinical evidence for fibrinolytic therapy as a reperfusion strategy in pregnancy and it is best avoided as the risk of haemorrhage outweighs the possible benefit of treatment. Patients with a prosthetic heart valve that present with a disappearance of the prosthetic heart sounds or a new murmur should get an urgent cardiac ultrasound to rule out a thrombosed prosthetic valve. Anaesthesia-related causes are an increasing cause of maternal morbidity and mortality.

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Investigation into the effects of lead shielding for fetal dose reduction in CT pulmonary angiography

Cited by 49 publications

References 20 publications

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

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

Diagnosing venous thromboembolism in pregnancy

Managing acute collapse in pregnant women

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