Impact of active dose management on radiation exposure and image quality in computed tomography: An observational study in 1315 patients

Abstract Background Chest radiograph (CXR) prescribing pattern and practice vary widely among pediatric intensive care units (PICU). ‘On demand’ approach is increasingly recommended as against daily ‘routine’ CXRs; however, the real-world practice is largely unknown. Methods This was a prospective observational study performed in children younger than 12 years admitted to PICU of a tertiary care teaching hospital in India. Data were collected on all consecutive CXRs performed between December 2016 and April 2017. The primary outcome was to assess the factors that were associated with higher chest radiograph prescriptions in PICU. Secondary outcomes were to study the indications, association with mechanical ventilation, image quality and avoidable radiation exposure. Results Of 303 children admitted during the study period, 159 underwent a total of 524 CXRs in PICU. Median (IQR) age of the study cohort was 2 (0.6–5) years. More than two thirds [n = 115, 72.3%] were mechanically ventilated. Most CXRs (n = 449, 85.7%) were performed on mechanically ventilated patients, amounting to a median (IQR) of 3 (2–5) radiographs per ventilated patient. With increasing duration of ventilation, the number of CXRs proportionately increased in the first two weeks of mechanical ventilation. In non-ventilated children, about two thirds (68%) underwent only one CXR. Majority of the prescriptions were on demand (n = 461, 88%). Most common indications were peri-procedure prescriptions (37%) followed by evaluation for respiratory disease status (24%). About 40% CXRs resulted in interventions; adjustment in ventilator settings (13.5%) was the most frequent intervention. In 26% (n = 138) of radiographs, image quality required improvement. One or more additional body part exposure other than chest and upper abdomen were noted 336 (64%) images. Children with > 3 CXR had higher PRISM III score, more often mechanically ventilated, had higher number of indwelling devices [mean (SD) 2.6 (1.2) vs. 1.7 (1.0)] and stayed longer in PICU [median (IQR) 11(7.5–18.5) vs. 6 (3–9)]. Conclusion On demand prescription was the prevalent practice in our PICU. Most non-ventilated children underwent only one CXR while duration of PICU stay and the number of devices determined the number of CXRs in mechanically ventilated children. Quality improvement strategies should concentrate on the process of acquisition of images and limiting the radiation exposure to unwanted body parts.

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Ultra low-dose single photon emission computed tomography myocardial perfusion imaging

International Journal of Diagnostic Imaging ◽

10.5430/ijdi.v1n2p54 ◽

2014 ◽

Vol 1 (2) ◽

pp. 54

Author(s):

William B. Nelson ◽

Chad M. House ◽

Patricia K. Turnquist ◽

Jenny M. Spence ◽

Mary A. Anstadt ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Exposure ◽

Low Dose ◽

Single Photon ◽

Photon Emission ◽

Emission Computed Tomography ◽

Single Photon Emission ◽

Single Photon Emission Computed ◽

Photon Emission Computed Tomography

Background: Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) provides excellent diagnostic and prognostic information. A primary limitation of SPECT is radiation exposure. New cadmium zinc telluride (CZT) technology has allowed for reduced radiation exposure. Methods: A cohort of 414 consecutive patients undergoing very low-dose SPECT MPI utilizing CZT technology was analyzed. Patients received rest/stress dosing strategies of 111/333, 148/444, 222/666, 296/888, 370/1110 Megabecquerels (MBq) (3/9, 4/12, 6/18, 8/24, 10/30 millicuries) depending on their weight and body mass index. Image quality was visually assessed by the reading cardiologist (scale: 1 = poor; 2 = fair; 3 = good; 4 = excellent). Results: 58% of patients received 111/333MBq, 22% received 148/444MBq, 13% received 222/666MBq, 6% received 296/888MBq, and 1% received 370/1110MBq. The estimated radiation dose was 3.6, 4.8, 7.2, 9.6, and 12 millisieverts respectively. The average image quality for the cohort was 3.3 ± 0.7. The rest/stress counts (103) for 111/333 and 148/444 groups were 532 ± 212/1718 ± 525 and 545 ± 177/1748 ± 399, while the rest/stress counts (103) for the 222/666 and 296/888 groups were 673 ± 178/2235 ± 923 and 764 ± 249/2588 ± 788 respectively. The 111/333 and 148/444 groups had significantly lower counts than the 222/666 and 296/888 groups, but only the 296/888 group had a significant difference in image quality when compared to the 111/333 group, with the 111/333 group having better image quality. Conclusion: CZT technology permits rapid, very low-dose MPI studies to be performed, thus, reducing the radiation exposure for patients, while still providing high quality, diagnostic perfusion results. The majority of our patients were imaged at less than 4mSv.

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