Assessment of Patient and Occupational Dose in Established and New Applications of MDCT Fluoroscopy

Joemai, Raoul M. S.; Zweers, D.; Obermann, Wim R.; Geleijns, Jacob

doi:10.2214/ajr.08.1765

Cited by 48 publications

(23 citation statements)

References 18 publications

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“…The effective dose at isocenter was derived from the absolute dose (D center ) times the scan length (nominally 20 cm) and organ-specific weighting factor for distal extremities (F extremity ¼ 0.0005 mSv=mGy Á cm). 37,38 …”

Section: Iid2 Imaging Dosementioning

confidence: 99%

A dedicated cone‐beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

et al. 2011

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Purpose: This paper reports on the design and initial imaging performance of a dedicated conebeam CT (CBCT) system for musculoskeletal (MSK) extremities. The system complements conventional CT and MR and offers a variety of potential clinical and logistical advantages that are likely to be of benefit to diagnosis, treatment planning, and assessment of therapy response in MSK radiology, orthopaedic surgery, and rheumatology. Methods: The scanner design incorporated a host of clinical requirements (e.g., ability to scan the weight-bearing knee in a natural stance) and was guided by theoretical and experimental analysis of image quality and dose. Such criteria identified the following basic scanner components and system configuration: a flat-panel detector (FPD, Varian 3030þ, 0.194 mm pixels); and a low-power, fixed anode x-ray source with 0.5 mm focal spot (SourceRay XRS-125-7K-P, 0.875 kW) mounted on a retractable C-arm allowing for two scanning orientations with the capability for side entry, viz. a standing configuration for imaging of weight-bearing lower extremities and a sitting configuration for imaging of tensioned upper extremity and unloaded lower extremity. Theoretical modeling employed cascaded systems analysis of modulation transfer function (MTF) and detective quantum efficiency (DQE) computed as a function of system geometry, kVp and filtration, dose, source power, etc. Physical experimentation utilized an imaging bench simulating the scanner geometry for verification of theoretical results and investigation of other factors, such as antiscatter grid selection and 3D image quality in phantom and cadaver, including qualitative comparison to conventional CT. Results: Theoretical modeling and benchtop experimentation confirmed the basic suitability of the FPD and x-ray source mentioned above. Clinical requirements combined with analysis of MTF and DQE yielded the following system geometry: a $55 cm source-to-detector distance; 1.3 magnification; a 20 cm diameter bore (20 Â 20 Â 20 cm 3 field of view); total acquisition arc of $240 . The system MTF declines to 50% at $1.3 mm À1 and to 10% at $2.7 mm À1, consistent with submillimeter spatial resolution. Analysis of DQE suggested a nominal technique of 90 kVp (þ0.3 mm Cu added filtration) to provide high imaging performance from $500 projections at less than $0.5 kW power, implying $6.4 mGy (0.064 mSv) for low-dose protocols and $15 mGy (0.15 mSv) for high-quality protocols. The experimental studies show improved image uniformity and contrast-tonoise ratio (without increase in dose) through incorporation of a custom 10:1 GR antiscatter grid. Cadaver images demonstrate exquisite bone detail, visualization of articular morphology, and softtissue visibility comparable to diagnostic CT (10-20 HU contrast resolution). Conclusions:The results indicate that the proposed system will deliver volumetric images of the extremities with soft-tissue contrast resolution comparable to diagnostic CT and improved spatial resolution at potentially reduced dose. Cascaded sys...

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Section: Iid2 Imaging Dosementioning

confidence: 99%

A dedicated cone‐beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

et al. 2011

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“…Hence, interventional radiologists are exposed to a considerable amount of scattered radiation while standing next to the patient during the intervention (21). In general, radiation exposure in CT interventions should follow the term ''as low as reasonable achievable'' (ALARAprinciple), especially because exposure times during CT-guided procedures can be long compared with diagnostic CT acquisitions (22). In interventional cardiology a recent multicenter study has compared the prevalence of different stages and types of cataracts in an exposed group of interventional cardiologists with an unexposed control group of non-interventional cardiologists, while taking into account other risk factors for cataracts, use of radiation protection tools, and exposure level (6).…”

Section: Discussionmentioning

confidence: 99%

Radiation exposure of the radiologist’s eye lens during CT-guided interventions

et al. 2014

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“…Tsalafoutas et al [25] report an effective dose of 23 mSv during conventional CT-guided biopsies in which unenhanced, intervention, and control post-procedure CT data acquisitions were performed. Other studies report a lower effective dose (7.1–12 mSv) during CT-guided biopsies; however in these procedures no final post-procedure CT data acquisition was performed to check for possible complications [26, 27]. …”

Section: Discussionmentioning

confidence: 99%

3D cone-beam CT guidance, a novel technique in renal biopsy—results in 41 patients with suspected renal masses

et al. 2012

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ObjectiveTo determine whether 3D cone-beam computed tomography (CBCT) guidance allows safe and accurate biopsy of suspected small renal masses (SRM), especially in hard-to-reach anatomical locations.Materials and methodsCBCT guidance was used to perform 41 stereotactic biopsy procedures of lesions that were inaccessible for ultrasound guidance or CT guidance. In CBCT guidance, a 3D-volume data set is acquired by rotating a C-arm flat-panel detector angiosystem around the patient. In the data set, a needle trajectory is determined and, after co-registration, a fusion image is created from fluoroscopy and a slice from the data set, enabling the needle to be positioned in real time.ResultsOf the 41 lesions, 22 were malignant, 17 were benign, and 2 were nondiagnostic. The two nondiagnostic lesions proved to be renal cell carcinoma. There was no growth during follow-up imaging of the benign lesions (mean 29 months). This resulted in a sensitivity, specificity, PPV, NPV, and accuracy of 91.7, 100, 100, 89.5, and 95.1%, respectively. Mean dose-area product value was 44.0 Gy·cm2 (range 16.5–126.5). There was one minor bleeding complication.ConclusionWith CBCT guidance, safe and accurate biopsy of a suspected SRM is feasible, especially in hard-to-reach locations of the kidney.Key Points• Cone-beam computed tomography has potential advantages over conventional CT for interventional procedures.• CBCT guidance incorporates 3D CBCT data, fluoroscopy, and guidance software.• In hard-to-reach renal masses, CBCT guidance offers an alternative biopsy method.• CBCT guidance offers good outcome and safety and has potential clinical significance.

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Assessment of Patient and Occupational Dose in Established and New Applications of MDCT Fluoroscopy

Cited by 48 publications

References 18 publications

A dedicated cone‐beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

A dedicated cone‐beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

Radiation exposure of the radiologist’s eye lens during CT-guided interventions

3D cone-beam CT guidance, a novel technique in renal biopsy—results in 41 patients with suspected renal masses

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