Patient size matters: Effect of tube current modulation on size‐specific dose estimates (SSDE) and image quality in low‐dose lung cancer screening CT

Barreto, Izabella; Verma, Nupur; Quails, Nathan; Olguín, Catherine; Correa, Nathalie; Mohammed, Tan-Lucien H.

doi:10.1002/acm2.12857

Cited by 12 publications

(6 citation statements)

References 21 publications

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“…The radiation dose increased as the patient body size increased. This finding was consistent with findings reported in previous studies [ 22 – 24 ]. In the study which used fixed tube current (FTC) and tube current modulation (TCM) on SSDE and image quality in lung cancer screening CT, Barreto [ 24 ] demonstrated that SSDE increased exponentially as patient size increased, and all images were still deemed clinically acceptable.…”

Section: Discussionsupporting

confidence: 94%

“…This finding was consistent with findings reported in previous studies [ 22 – 24 ]. In the study which used fixed tube current (FTC) and tube current modulation (TCM) on SSDE and image quality in lung cancer screening CT, Barreto [ 24 ] demonstrated that SSDE increased exponentially as patient size increased, and all images were still deemed clinically acceptable. Furthermore, we found that the radiation exposure dose for chest CT examinations in our study was lower than China DRLs and updated 2017 ACR DRLs.…”

Section: Discussionsupporting

confidence: 94%

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Size-specific dose estimates of adult, chest computed tomography examinations: Comparison of Chinese and updated 2017 American College of Radiology diagnostic reference levels based on the water-equivalent diameter

Hu¹,

Gou²,

Lin³

et al. 2021

PLoS ONE

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Rationale and objectives This study aimed to compare the volume computed tomography dose index (CTDIvol), dose length product (DLP), and size-specific dose estimate (SSDE), with the China and updated 2017 American College of Radiology (ACR) diagnostic reference levels (DRLs) in chest CT examinations of adults based on the water-equivalent diameter (Dw). Materials and methods All chest CT examinations conducted without contrast administration from January 2020 to July 2020 were retrospectively included in this study. The Dw and SSDE of all examinations were calculated automatically by “teamplay”. The CTDIvol and DLP were displayed on the DICOM-structured dose report in the console based on a 32cm phantom.The differences in patient CTDIvol, DLP, and SSDE values between groups were examined by the one-way ANOVA. The differences in patient CTDIvol, DLP, and SSDE values between the updated 2017 ACR and the China DRLs were examined with one sample t-tests. Results In total 14666 chest examinations were conducted in our study. Patients were divided into four groups based on Dw:270 (1.84%) in 15–20 cm group, 10287 (70.14%) in the 21–25 cm group, 4097 (27.94%) in the 26–30 cm group, and 12 (0.08%) patients had sizes larger than 30 cm. CTDIvol, DLP, and SSDE increased as a function of Dw (p<0.05). CTDIvol was smaller than SSDE among groups (p<0.05). The mean CTDIvol and DLP values were lower than the 25th, 50th, and 75th percentile of the China DRLs (p <0.05). The CTDIvol, DLP, and SSDE were lower than the 50th and 75th percentiles of the updated 2017 ACR DRLs (p <0.05) among groups. Conclusions SSDE takes into account the influence of the scanning parameters, patient size, and X-ray attenuation on the radiation dose, which can give a more realistic estimate of radiation exposure dose for patients undergoing CT examinations. Establishing hospital’s own DRL according to CTDIvol and SSDE is very important even though the radiation dose is lower than the national DRLs.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionsupporting

confidence: 94%

Size-specific dose estimates of adult, chest computed tomography examinations: Comparison of Chinese and updated 2017 American College of Radiology diagnostic reference levels based on the water-equivalent diameter

Hu¹,

Gou²,

Lin³

et al. 2021

PLoS ONE

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“…CTDI vol increased by 2.3-fold when body size increased from underweight to overweight phantoms (table 1). This finding agrees with Barreto et al reporting that CTDI vol increases exponentially with the effective diameter of patients [33]. The dosimetric errors increased as the age group of phantoms increased because the variability in body size was greater in older phantoms than in younger ones, as shown in the breadth of weight distribution at the same height (figure 1).…”

Section: Discussionsupporting

confidence: 91%

CT organ dose calculator size adaptive for pediatric and adult patients

Lee¹,

Yeom²,

Folio³

2022

Biomed. Phys. Eng. Express

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Background: Although computed tomography (CT) has played a critical role in medical care since its introduction in the 1970s, its potential long-term risk of adverse health effects has been of concern. It is crucial to accurately estimate the radiation dose delivered to the patient’s critical organs to ensure the dose is As Low As Reasonably Achievable. However, organ-level dose calculation tools for pediatric and adult patients with various body sizes are rare. We extended the existing CT organ dose calculator, NCICT 1.0, which is based on reference-size phantoms, to include body size-specific pediatric and adult phantoms. Methods: We calculated body size-specific organ doses normalized to CTDIvol by using a library of 158 pediatric and 193 adult computational human phantoms with various body sizes combined with a Monte Carlo radiation transport code, MCNP6. We also created a library of generic tube current modulation (TCM) profiles for the phantom library using a ray-tracing algorithm and implemented them into organ dose calculations. We validated organ doses for the body size-specific phantoms using those calculated from ten abdominal CT patients. We also evaluated potential dosimetric errors caused by only using reference phantoms for patients with different body sizes. Results: Organ dose coefficients and TCM profiles for 351 pediatric and adult body size-specific phantoms were implemented into NCICT 2.0. The dose coefficients from the ten abdominal CT patients agreed with those from the program within 13%. The organ doses for the overweight phantoms were overestimated by over 80% when only reference size phantoms were used. Conclusion: We confirmed that the upgraded dose calculator NCICT 2.0 could substantially reduce potential dosimetric errors caused by using only reference size phantoms. The program should be useful for the radiology community to accurately monitor organ doses for pediatric and adult CT patients with various body sizes.

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“…The significance of SSDE in the evaluation of organ doses is also highlighted. Previous works [11,12,27,28] demonstrated that this quantity is correlated with patient organ doses. Our results demonstrated strong statistical correlation associating SSDE with inside and distributed organ doses in the chest and abdomen-pelvis cohorts and it was also statistically significant on the periphery and outside organ doses in the last case.…”

Section: Discussionmentioning

confidence: 96%

Diagnostic reference level quantities for adult chest and abdomen-pelvis CT examinations: correlation with organ doses

et al. 2023

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Objectives To evaluate correlations between DRL quantities (DRLq) stratified into patient size groups for non-contrast chest and abdomen-pelvis CT examinations in adult patients and the corresponding organ doses. Methods This study presents correlations between DRLq (CTDIvol, DLP and SSDE) stratified into patient size ranges and corresponding organ doses shared in four groups: inside, peripheral, distributed and outside. The demographic, technical and dosimetric parameters were used to identify the influence of these quantities in organ doses. A robust statistical method was implemented in order to establish these correlations and its statistical significance. Results Median values of the grouped organ doses are presented according to the effective diameter ranges. Organ doses in the regions inside the imaged area are higher than the organ doses in peripheral, distributed and outside regions, excepted to the peripheral doses associated with chest examinations. Different levels of statistical significance between organ doses and the DRLq were presented. Conclusions Correlations between DRLq and target-organ doses associated with clinical practice can support guidance’s to the establishment of optimization criteria. SSDE demonstrated to be significant in the evaluation of organ doses is also highlighted. The proposed model allows the design of optimization actions with specific risk-reduction results.

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Patient size matters: Effect of tube current modulation on size‐specific dose estimates (SSDE) and image quality in low‐dose lung cancer screening CT

Cited by 12 publications

References 21 publications

Size-specific dose estimates of adult, chest computed tomography examinations: Comparison of Chinese and updated 2017 American College of Radiology diagnostic reference levels based on the water-equivalent diameter

Size-specific dose estimates of adult, chest computed tomography examinations: Comparison of Chinese and updated 2017 American College of Radiology diagnostic reference levels based on the water-equivalent diameter

CT organ dose calculator size adaptive for pediatric and adult patients

Diagnostic reference level quantities for adult chest and abdomen-pelvis CT examinations: correlation with organ doses

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