Dose Reduction to Anterior Surfaces With Organ-Based Tube-Current Modulation: Evaluation of Performance in a Phantom Study

Duan, Xinhui; Wang, Jia; Christner, Jodie A.; Leng, Shuai; Grant, Katharine L.; McCollough, Cynthia H.

doi:10.2214/ajr.10.6061

Cited by 101 publications

(63 citation statements)

References 19 publications

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“…In the phantom experiment of this study, the changes in radiation exposure with X-CARE use reduction at the midline of the precordial region and increase at the midline of the dorsal region are consistent with those of previous reports 2,3 . In the clinical cases, the use of X-CARE reduced the radiation dose ratios at the midline of the precordial region and the medial sides of both breasts by approximately 14 22 , which was less for the precordial region than in the phantom experiment.…”

Section: Discussionsupporting

confidence: 92%

Reduced Radiation Exposure to the Mammary Glands in Thoracic Computed Tomography using Organ-based Tube-current Modulation

Munechika

Ohgiya

Gokan

et al. 2013

Showa Univ J Med Sci

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: Organ-based tube-current modulation has been used to reduce radiation exposure to speci c organs. However, there are no reports yet published on reducing radiation exposure in clinical cases. In this study, we assessed the reduction in radiation exposure to the mammary glands during thoracic computed tomography CT using X-CARE. In a phantom experiment, the use of X-CARE reduced radiation exposure at the midline of the precordial region by a maximum of 45.1 . In our corresponding clinical study, CT was performed using X-CARE in 15 patients, and without X-CARE in another 15. Compared to the non-X-CARE group, radiation exposure was reduced in the X-CARE group at the midline of the precordial region by 22.3 P 0.05 and at the medial sides of the right and left breasts by 16.8 and 14.2 , respectively P 0.05 for each . Analysis of the visual quality of CT images as well as CT values for the muscles of the chest walls showed no difference in either assessment between the X-CARE and non-Xcare groups P 0.05 . X-CARE thus reduced radiation exposure at the midline of the precordial region and allowed us to obtain consistent CT values without increasing noise. However, this study revealed increases in radiation exposure at the lateral sides of the breasts. It is conceivable that patients breasts were laterally displaced by gravity under the standard thoracic imaging conditions. Further studies that consider factors such as body size and adjustment of imaging conditions may be needed in the future.

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Section: Discussionsupporting

confidence: 92%

Reduced Radiation Exposure to the Mammary Glands in Thoracic Computed Tomography using Organ-based Tube-current Modulation

Munechika

Ohgiya

Gokan

et al. 2013

Showa Univ J Med Sci

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“…Nevertheless, to the best of our knowledge, this study still represents the largest database for pediatric organ dose estimates. Third, our study did not specifically address nuances associated with tube current modulation (30), bismuth shielding (31), or organ-based dose modulation (32), topics that we aim to adddress in future studies. Fourth, in a direct application of our coefficients to assess the organ doses for a real patient undergoing a CT examination, certain sources of error included the following: organ size and PEDIATRIC IMAGING: Organ Dose Estimation in Pediatric Chest and Abdominopelvic CT Tian et al patient size and the CTDI vol for pediatric chest and abdominopelvic CT examinations.…”

Section: Pediatric Imaging: Organ Dose Estimation In Pediatric Chestmentioning

confidence: 99%

Pediatric Chest and Abdominopelvic CT: Organ Dose Estimation Based on 42 Patient Models

Tian¹,

Li²,

Segars³

et al. 2013

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Purpose:To estimate organ dose from pediatric chest and abdominopelvic computed tomography (CT) examinations and evaluate the dependency of organ dose coefficients on patient size and CT scanner models. Materials and Methods:The institutional review board approved this HIPAA-compliant study and did not require informed patient consent. A validated Monte Carlo program was used to perform simulations in 42 pediatric patient models (age range, 0-16 years; weight range, 2-80 kg; 24 boys, 18 girls).Multidetector CT scanners were modeled on those from two commercial manufacturers (LightSpeed VCT, GE Healthcare, Waukesha, Wis; SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). Organ doses were estimated for each patient model for routine chest and abdominopelvic examinations and were normalized by volume CT dose index (CTDI vol ). The relationships between CTDI vol -normalized organ dose coefficients and average patient diameters were evaluated across scanner models. Results:For organs within the image coverage, CTDI vol -normalized organ dose coefficients largely showed a strong exponential relationship with the average patient diameter (R 2 . 0.9). The average percentage differences between the two scanner models were generally within 10%. For distributed organs and organs on the periphery of or outside the image coverage, the differences were generally larger (average, 3%-32%) mainly because of the effect of overranging. Conclusion:It is feasible to estimate patient-specific organ dose for a given examination with the knowledge of patient size and the CTDI vol . These CTDI vol -normalized organ dose coefficients enable one to readily estimate patient-specific organ dose for pediatric patients in clinical settings. This dose information, and, as appropriate, attendant risk estimations, can provide more substantive information for the individual patient for both clinical and research applications and can yield more expansive information on dose profiles across patient populations within a practice.q RSNA, 2013

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“…The mammary glands, thyroid glands, and eye lenses thus receive a lower dose as the system reduces the tube current when the tube comes close to these organs. To compensate for this reduction, the tube current in the X-ray projection from the opposite side is increased thus leaving mean image noise constant [51,52]. This application can be very useful in Clin Transl Imaging (2014) 2:557-569 565 SPECT/CT systems for sparing the lens in CT head acquisitions, as SPECT/CT can acquire only axial and not transaxial images with tilted gantry, because of problems in image registration.…”

Section: Organ-based and Automatic Kv Selectionmentioning

confidence: 99%

SPECT/CT radiation dosimetry

Ferrari

Marco

Origgi

et al. 2014

Clin Transl Imaging

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Single-photon emission computed tomography combined with X-ray computed tomography (SPECT/CT) improves diagnostic accuracy by allowing better localization and definition of scintigraphic findings. However, the combined acquisition of functional and anatomical images can substantially increase radiation exposure to patients, particularly when using a hybrid system with diagnostic CT capabilities. At the same time, the introduction of new SPECT and CT reconstruction techniques (based on the use of iterative algorithms), and of CT automatic dose modulation techniques, has opened the way for possible reductions in patient dose and/or improvements of image quality. It is, therefore, essential to carefully balance the diagnostic needs and the radiation protection requirements, optimizing the choice of radiopharmaceutical and administered activity, and the image acquisition and processing modalities both in SPECT and in CT. This is particularly important in the case of pediatric examinations. In short, to maximize benefit to patients, SPECT/CT studies have to be optimized, adopting dose-reduction measures both from CT and SPECT practices. In SPECT, shorter lived gamma emitters should be preferred and the amount of activity administered must be carefully adjusted to the patient's size. In CT, scanning parameters (scanning length, tube current, tube voltage, filtration, collimation, slice thickness, pitch, automatic dose modulation method, reconstruction technique, and image processing) must be chosen carefully, remembering that normally the scanned images are used only for the purposes of attenuation correction and/or a more precise localization of scintigraphic findings, which require lower quality and consequently entail a lower dose to the patient. On the other hand, good quality diagnostic CT images, obtained at higher dose levels, are necessary if a diagnostic CT examination must still be planned for the patient. The purpose of this review on SPECT/CT radiation dosimetry is to provide updated information on the total effective dose and total equivalent doses to critical organs due to both radiopharmaceutical administration and CT scan modality for both adults and pediatric patients. The use of new solid-state detectors (cadmium zinc telluride) for SPECT cameras will also be considered. Finally, the means of easily determining SPECT/CT dose to patients will be provided.

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Dose Reduction to Anterior Surfaces With Organ-Based Tube-Current Modulation: Evaluation of Performance in a Phantom Study

Abstract: Organ-based tube-current modulation can reduce the dose to the anterior surface of patients without increasing image noise by commensurately increasing the dose to the posterior surface. This technique can reduce the dose to anterior radiosensitive organs for head and thoracic CT scans.

Cited by 101 publications

References 19 publications

Reduced Radiation Exposure to the Mammary Glands in Thoracic Computed Tomography using Organ-based Tube-current Modulation

Reduced Radiation Exposure to the Mammary Glands in Thoracic Computed Tomography using Organ-based Tube-current Modulation

Pediatric Chest and Abdominopelvic CT: Organ Dose Estimation Based on 42 Patient Models

SPECT/CT radiation dosimetry

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