Organ-based tube current modulation in chest CT. A comparison of three vendors

Abstract

Introduction: Organ-based tube current modulation (OBTCM) is designed for anterior dose reduction in Computed Tomography (CT). The purpose was to assess dose reduction capability in chest CT using three organ dose modulation systems at different kVp settings. Furthermore, noise, diagnostic image quality and tumour detection was assessed. Methods: A Lungman phantom was scanned with and without OBTCM at 80e135/140 kVp using three CT scanners; Canon Aquillion Prime, GE Revolution CT and Siemens Somatom Flash. Thermo-luminescent dosimeters were attached to the phantom surface and all scans were repeated five times. Image noise was measured in three ROIs at the level of the carina. Three observers visually scored the images using a fivestep scale. A Wilcoxon Signed-Rank test was used for statistical analysis of differences. Results: Using the GE revolution CT scanner, dose reductions between 1.10 mSv (12%) and 1.56 mSv (24%) (p < 0.01) were found in the anterior segment and no differences posteriorly and laterally. Total dose reductions between 0.64 (8%) and 0.91 mSv (13%) were found across kVp levels (p < 0.00001). Maximum noise increase with OBTCM was 0.8 HU. With the Canon system, anterior dose reductions of 6e10% and total dose reduction of 0.74e0.76 mSv across kVp levels (p < 0.001) were found with a maximum noise increase of 1.1 HU. For the Siemens system, dose increased by 22e51% anteriorly; except at 100 kVp where no dose difference was found. Noise decreased by 1 to 1.5 HU. Conclusion: Organ based tube current modulation is capable of anterior and total dose reduction with minimal loss of image quality in vendors that do not increase posterior dose. Implications for practice: This research highlights the importance of being familiar with dose reduction technologies.

Radiation dose reduction considerations and imaging patterns of ground glass opacities in coronavirus: risk of over exposure in computed tomography

“…3 63-year-old male presented with fever, dry cough, and chest pain for 4 days. He had a positive PCR and confirmed peripheral and central GGO bilaterally which was confirmed it was SARS-CoV-2 4: organ-based tube current modulation [36] and 5: the radiologist screening unnecessary requests for CT scans [37].…”

The impact of vertical off-centering on image noise and breast dose in chest CT with organ-based tube current modulation: A phantom study

“…This observation was similar to our study results, as we found a 20% to 25% increase in the posterior mediastinum and posterior lung region doses in our MC simulations. Mussmann et al [43] also reported that Siemens OBTCM may not automatically be advantageous for the patients by observing higher breast doses with OBTCM than without it. They assumed this to be related partly on the lower pitch value used in the OBTCM chest CT protocol.…”

“…Moreover, Siemens approach compensates anteriorly reduced tube current by increasing the current during the posterior projections, whereas GE and Canon approaches do not [6,15,[36][37][38]. In chest CT, the overall dose-reduction percentages yielded by the OBTCM methods for the breasts have been reported to be between 5% and 48% compared to chest CT scan protocols utilizing normal TCM [6,15,[36][37][38][39][40][41][42][43]. However, it has also been warned that the dose may increase in some parts of the breast tissue outside the reduced dose zone [12,37,38,40,41].…”

Design of a 3D printed coronary artery model for CT optimization

“…Additionally, it is not possible to inject contrast media into such phantoms. 3,5,6 Coronary CT angiography (CCTA) is a minimally invasive examination compared to invasive coronary angiography and its use is growing considerably in light of recent clinical guidelines. 7 Regular optimization of CCTA is a necessity due to the constantly new technical developments that accrue in CT, coupled with reports of heterogenous radiation dose and image quality between imaging sites.…”