Precise Image and Precise Position, a tandem for routine low dose without compromising on image quality

The Philips Incisive CT scanner embeds with CT SmartWorkflow a number of features involving artificial intelligence to, among other things, simplify patient set-up, improve image quality and significantly reduce patient irradiation. We met Dr. Jean Goupil, Hospital Radiologist Practitioner and Dr. Joël Greffier, Physicist, both working at the University Hospital of Nîmes where a modality of this type is installed, for a detailed feedback.

Thema Radiology: The CHU of Nîmes made the choice, in September 2021, within the imaging unit of the Cancer Institute of Gard, to acquire an Incisive CT scanner equipped with the CT SmartWorkflow solution. What are the contributions of this modality for oncological imaging care?

Dr. Jean Goupil: The name of this solution (CT SmartWorkflow) probably comes from its ability to save us time and energy in positioning patients and acquiring images. It is unanimously accepted by technicians as to its ergonomics, in particular with the tablet that they can use for different functions, such as mobilizing the tray, administering the injection of contrast product or triggering X-rays. And since we do not realize almost exclusively than injected examinations, this machine simplifies our lives and helps us to work more quickly, which allows us to improve the time spent by the technologist with the patient. We could also carry out more examinations, but that does not correspond to our philosophy.

“A neural network trained on patients to reproduce filtered images from low-dose raw data”

TR: This SmartWorkflow CT solution embedded on the Incisive CT allows dose reductions without compromising image quality. Can you describe how it works?

Dr. Joel Registrar: First, in CT SmartWorkflow, there is Precise Position, the tracking performed by cameras equipped with an AI algorithm, installed on the ceiling in the examination area, in order to automatically place the patient at the isocenter scanner and identify its morphotype. This makes it possible to improve the precision of the positioning of the patient and to standardize/homogenize the practices between the manipulators. A patient well centered at the isocenter improves the modulation of intensity and therefore reduces the doses and improves the quality of the examination.

Then there is Precise Image, an image reconstruction algorithm that is based on deep learning. The neural network of this algorithm is trained to reproduce the appearance (amplitude and noise texture) of normal-dose filtered back-projection images from the raw data of low-dose scanners. To avoid overexposing patients, low dose images are generated from normal dose images using a simulation technique to accurately model photons and electronic noise. This algorithm consists of 5 levels: Harder/Hard/Standard/Soft/Softer.

“Very low levels of irradiation for routine low dose”

TR: What does this new method of reconstructing raw data bring to your practice?

155x155xJoel Greffier.jpeg.pagespeed.ic.GTCWLtnMB9Dr. Joel Registrar: Compared to the available iterative algorithm (iDose4) on this scanner, noise levels are lower and spatial resolution is improved with Standard/Soft/Softer levels. Image texture is less smoothed with all levels except Softer. We now use this algorithm routinely for all our protocols, most of the time, the Soft level. Radiologists are satisfied with the overall and diagnostic quality of the images most of the time and we pass on our questions and requests to Philips to contribute to the continuous improvement of this solution, of which we are among the first users.

TR: And in terms of dosimetry, can we imagine that the reduction in mA reduces the patient’s irradiation by the same amount?

Dr. Joel Registrar: We are evaluating the doses delivered for all patients exposed to this machine every week. After optimization of the acquisition and reconstruction parameters, in particular the use of Precise Image, for the different protocols, our dose levels are at the level of 25th percentile of the DRLs, which corresponds to low-dose acquisitions. We are also experimenting, pre-clinically, with the possibility of using ultra-low dose for explorations with high spontaneous contrast such as the thorax or the osteoarticular.

TR: What is the feedback from users on a daily basis in their practice?

Dr. Jean Goupil: For the manipulators, as we have already mentioned, the ergonomics of the modality, which allows an easier installation of the patient, is very appreciated. For practitioners, the suppression of noise on the image and the improvement of contours, while smoothing contrasts, provides reading comfort and increased confidence and security in the interpretation of images.

Interview by Bruno Benque

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Precise Image and Precise Position, a tandem for routine low dose without compromising on image quality

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