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Management of pediatric radiation dose using GE fluoroscopic equipment.

Belanger B, Boudry J - Pediatr Radiol (2006)

Bottom Line: In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an estimate of its dose reduction potential.Finally, two recently developed imaging techniques and their potential effect on dose utilization are discussed.Specifically, we discuss the dose benefits of rotational angiography and low frame rate imaging with advanced image processing in lieu of higher-dose digital subtraction.

View Article: PubMed Central - PubMed

Affiliation: GE Healthcare Technologies, 9900 Innovation Drive, RP-2124, Wauwatosa, WI 53226, USA. Barry.Belanger@med.ge.com

ABSTRACT
In this article, we present GE Healthcare's design philosophy and implementation of X-ray imaging systems with dose management for pediatric patients, as embodied in its current radiography and fluoroscopy and interventional cardiovascular X-ray product offerings. First, we present a basic framework of image quality and dose in the context of a cost-benefit trade-off, with the development of the concept of imaging dose efficiency. A set of key metrics of image quality and dose efficiency is presented, including X-ray source efficiency, detector quantum efficiency (DQE), detector dynamic range, and temporal response, with an explanation of the clinical relevance of each. Second, we present design methods for automatically selecting optimal X-ray technique parameters (kVp, mA, pulse width, and spectral filtration) in real time for various clinical applications. These methods are based on an optimization scheme where patient skin dose is minimized for a target desired image contrast-to-noise ratio. Operator display of skin dose and Dose-Area Product (DAP) is covered, as well. Third, system controls and predefined protocols available to the operator are explained in the context of dose management and the need to meet varying clinical procedure imaging demands. For example, fluoroscopic dose rate is adjustable over a range of 20:1 to adapt to different procedure requirements. Fourth, we discuss the impact of image processing techniques upon dose minimization. In particular, two such techniques, dynamic range compression through adaptive multiband spectral filtering and fluoroscopic noise reduction, are explored in some detail. Fifth, we review a list of system dose-reduction features, including automatic spectral filtration, virtual collimation, variable-rate pulsed fluoroscopic, grid and no-grid techniques, and fluoroscopic loop replay with store. In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an estimate of its dose reduction potential. Finally, two recently developed imaging techniques and their potential effect on dose utilization are discussed. Specifically, we discuss the dose benefits of rotational angiography and low frame rate imaging with advanced image processing in lieu of higher-dose digital subtraction.

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Typical patient entrance skin exposure levels for fluoro and three record modes for the five different AutoEx trajectory families offered on the Innova 4100. Conditions are 20-cm field-of-view, 20-cm PMMA phantom
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Fig5: Typical patient entrance skin exposure levels for fluoro and three record modes for the five different AutoEx trajectory families offered on the Innova 4100. Conditions are 20-cm field-of-view, 20-cm PMMA phantom

Mentions: In order to fit the needs of different clinical applications, regional regulatory norms, and varying preferences of clinicians, several trajectory families are offered with the Innova and Precision 500 D products. Such families typically feature different dose levels and related optimization criteria. Figure 5 lists the offerings for the Innova 4100 and their typical dose levels. The first dose customization is performed at installation; one of five AutoExposure preferences is selected that best fits the needs of the customer. In addition, the user can select at installation between two distinct strategies for dose reduction in lower frame rate fluoroscopic modes. The first option, called ‘Maximum Dose Reduction– uses the same X-ray techniques for 15 fps and 7.5 fps as it would in the case of 30 fps, thus reducing the dose by factors of 2 and 4, respectively. Because of the characteristics of human visual perception, the application of this strategy results in a reduction of the perceived image quality in the lower frame rate modes compared to the 30 fps mode. The second option, ‘Balanced IQ/Dose– provides similar perceived image quality for all frame rates, which can be obtained by reducing the dose corresponding to 30 fps fluoro to approximately 75% for 15 fps and 50% for 7.5 fps [7]. For the families and frame rates offered, a 20:1 range of doses can be achieved. Figure 6 lists the trajectory families offered with Precision 500 D and typical dose levels. Families are offered for adult and pediatric modes. The pediatric mode is further divided into ‘grid out–and ‘grid in–modes. The grid out mode is primarily for young children, where the grid is kept out because of the lower scatter-to-primary ratio for dose reduction. The grid in mode is provided for larger children and adolescents, where scatter can cause significant image quality degradation and necessitates use of the grid. The maximum dose rate for both pediatric trajectories is 5 R/min, while for the adult trajectory it is 10 R/min. In all trajectory families, the variation in dose rate with frame rate follows the recommendations of Aufrichtig et al. [7]. Finally, trajectories are also developed to meet specific country regulations. The German trajectory is shown as an example. A dose range of about 6:1 is spanned proceeding from the adult trajectory family (30 fps) to the pediatric grid out family (3.75 fps). Including the German trajectory family would present an even larger range.Fig. 5


Management of pediatric radiation dose using GE fluoroscopic equipment.

Belanger B, Boudry J - Pediatr Radiol (2006)

Typical patient entrance skin exposure levels for fluoro and three record modes for the five different AutoEx trajectory families offered on the Innova 4100. Conditions are 20-cm field-of-view, 20-cm PMMA phantom
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2663641&req=5

Fig5: Typical patient entrance skin exposure levels for fluoro and three record modes for the five different AutoEx trajectory families offered on the Innova 4100. Conditions are 20-cm field-of-view, 20-cm PMMA phantom
Mentions: In order to fit the needs of different clinical applications, regional regulatory norms, and varying preferences of clinicians, several trajectory families are offered with the Innova and Precision 500 D products. Such families typically feature different dose levels and related optimization criteria. Figure 5 lists the offerings for the Innova 4100 and their typical dose levels. The first dose customization is performed at installation; one of five AutoExposure preferences is selected that best fits the needs of the customer. In addition, the user can select at installation between two distinct strategies for dose reduction in lower frame rate fluoroscopic modes. The first option, called ‘Maximum Dose Reduction– uses the same X-ray techniques for 15 fps and 7.5 fps as it would in the case of 30 fps, thus reducing the dose by factors of 2 and 4, respectively. Because of the characteristics of human visual perception, the application of this strategy results in a reduction of the perceived image quality in the lower frame rate modes compared to the 30 fps mode. The second option, ‘Balanced IQ/Dose– provides similar perceived image quality for all frame rates, which can be obtained by reducing the dose corresponding to 30 fps fluoro to approximately 75% for 15 fps and 50% for 7.5 fps [7]. For the families and frame rates offered, a 20:1 range of doses can be achieved. Figure 6 lists the trajectory families offered with Precision 500 D and typical dose levels. Families are offered for adult and pediatric modes. The pediatric mode is further divided into ‘grid out–and ‘grid in–modes. The grid out mode is primarily for young children, where the grid is kept out because of the lower scatter-to-primary ratio for dose reduction. The grid in mode is provided for larger children and adolescents, where scatter can cause significant image quality degradation and necessitates use of the grid. The maximum dose rate for both pediatric trajectories is 5 R/min, while for the adult trajectory it is 10 R/min. In all trajectory families, the variation in dose rate with frame rate follows the recommendations of Aufrichtig et al. [7]. Finally, trajectories are also developed to meet specific country regulations. The German trajectory is shown as an example. A dose range of about 6:1 is spanned proceeding from the adult trajectory family (30 fps) to the pediatric grid out family (3.75 fps). Including the German trajectory family would present an even larger range.Fig. 5

Bottom Line: In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an estimate of its dose reduction potential.Finally, two recently developed imaging techniques and their potential effect on dose utilization are discussed.Specifically, we discuss the dose benefits of rotational angiography and low frame rate imaging with advanced image processing in lieu of higher-dose digital subtraction.

View Article: PubMed Central - PubMed

Affiliation: GE Healthcare Technologies, 9900 Innovation Drive, RP-2124, Wauwatosa, WI 53226, USA. Barry.Belanger@med.ge.com

ABSTRACT
In this article, we present GE Healthcare's design philosophy and implementation of X-ray imaging systems with dose management for pediatric patients, as embodied in its current radiography and fluoroscopy and interventional cardiovascular X-ray product offerings. First, we present a basic framework of image quality and dose in the context of a cost-benefit trade-off, with the development of the concept of imaging dose efficiency. A set of key metrics of image quality and dose efficiency is presented, including X-ray source efficiency, detector quantum efficiency (DQE), detector dynamic range, and temporal response, with an explanation of the clinical relevance of each. Second, we present design methods for automatically selecting optimal X-ray technique parameters (kVp, mA, pulse width, and spectral filtration) in real time for various clinical applications. These methods are based on an optimization scheme where patient skin dose is minimized for a target desired image contrast-to-noise ratio. Operator display of skin dose and Dose-Area Product (DAP) is covered, as well. Third, system controls and predefined protocols available to the operator are explained in the context of dose management and the need to meet varying clinical procedure imaging demands. For example, fluoroscopic dose rate is adjustable over a range of 20:1 to adapt to different procedure requirements. Fourth, we discuss the impact of image processing techniques upon dose minimization. In particular, two such techniques, dynamic range compression through adaptive multiband spectral filtering and fluoroscopic noise reduction, are explored in some detail. Fifth, we review a list of system dose-reduction features, including automatic spectral filtration, virtual collimation, variable-rate pulsed fluoroscopic, grid and no-grid techniques, and fluoroscopic loop replay with store. In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an estimate of its dose reduction potential. Finally, two recently developed imaging techniques and their potential effect on dose utilization are discussed. Specifically, we discuss the dose benefits of rotational angiography and low frame rate imaging with advanced image processing in lieu of higher-dose digital subtraction.

Show MeSH
Related in: MedlinePlus