Abstract
Purpose
This study evaluated and compared energy consumption between automated breast ultrasound (ABUS) and handheld ultrasound (HHUS) systems during routine whole-breast ultrasound (US) examinations in clinical practice.
Methods
This prospective observational study included 320 consecutive patients who underwent breast US between July and October 2025. Four systems were used: two ABUS systems, designated ABUS-1 and ABUS-2, and two HHUS systems, designated HHUS-1 and HHUS-2. HHUS examinations were performed by four radiologists. Energy consumption was measured using a real-time power meter synchronized with system log files. Power consumption was analyzed in active, idle, and off modes. Average power in each mode, examination duration, and energy consumption during active scanning were calculated. Data were analyzed using the independent-samples t-test or Mann-Whitney U test with Bonferroni correction.
Results
In idle mode, ABUS systems consumed significantly less average power than HHUS systems (P<0.001). In off mode, both ABUS systems consumed 0 W, whereas HHUS systems continued to consume residual power. During active scanning, ABUS systems had shorter examination durations than HHUS systems, with ABUS-1 showing the shortest duration. Energy consumption during active scanning was lowest for ABUS-1, which consumed approximately 47% less energy than HHUS-1 (P<0.001). Across all radiologists, both ABUS systems consistently showed lower energy consumption than HHUS-1.
Conclusion
Compared with HHUS, ABUS showed lower power use in idle and off modes and similar or lower energy consumption during active scanning. When clinically appropriate, preferential use of ABUS may improve energy sustainability while preserving clinical utility.
Keywords: Energy sustainability, Energy consumption, Breast ultrasound, Handheld ultrasound, Automated ultrasound
Graphical abstract
Introduction
As the adverse effects of climate change on global health and human well-being have become increasingly evident, governments, international health organizations, including the United Nations and World Health Organization, and the medical community, including radiology societies, have begun to take coordinated action [1–4]. In radiology, efforts to reduce greenhouse gas (GHG) emissions have focused on evaluating the energy consumption of imaging modalities, particularly computed tomography (CT) and magnetic resonance imaging (MRI), and developing strategies to improve energy efficiency without compromising diagnostic performance [4–8]. A recent radiology report estimated that CT and MRI together accounted for up to 0.77% of total global CO₂ emissions in 2016, with this value projected to increase by 30% by 2030 [9]. Ultrasound (US) is associated with substantially lower carbon emissions than CT and MRI; however, its environmental impact has been less extensively studied, and only a few reports have evaluated US energy consumption [10–12].
Breast cancer is the most common malignancy among women worldwide [13], and breast US is widely used for both diagnosis and screening. Traditionally, handheld US (HHUS) has been the standard method for whole-breast examination. In the updated 2025 Breast Imaging Reporting and Data System (BI-RADS) US lexicon [14], automated breast US (ABUS) is formally recognized as a whole-breast US examination modality alongside conventional HHUS. The clinical use of ABUS has expanded beyond screening asymptomatic women with dense breasts to include diagnostic applications such as preoperative staging of breast cancer, monitoring tumor response to neoadjuvant chemotherapy, and second-look evaluation after breast MRI [15–17].
Despite the advantages of US, including accessibility, cost-effectiveness, and avoidance of ionizing radiation, its environmental footprint has been minimally explored, and previous environmental analyses have not specifically addressed breast US [10,11,18–20]. Appropriate and efficient use of US may contribute to energy sustainability, and systematic assessments are needed to inform such strategies. To the authors’ knowledge, no previous study has specifically evaluated energy consumption associated with breast US examinations. Because most radiological energy-consumption studies have been retrospective [10,11,21,22], we designed this prospective study to obtain precise measurements of energy use for both HHUS and ABUS in routine clinical practice.
The purpose of this study was to investigate and compare the energy consumption of ABUS and HHUS systems used for whole-breast examination and to explore strategies for improving US resource management.
Materials and Methods
Compliance with Ethical Standards
This prospective observational study was approved by the Institutional Review Board of Korea University Ansan Hospital, and the requirement for written informed consent was waived because the study did not involve direct human participant intervention and collected only nonidentifiable operational data, including examination duration and energy consumption, generated during routine breast US examinations (approval No. 2025AS0322).
Study Participants
Sample size estimation is provided in the Supplementary Text 1.
Between July and October 2025, 320 consecutive patients scheduled to undergo whole-breast US examinations were enrolled (Fig. 1). Eligibility criteria were age ≥20 years and no prior history of breast surgery, vacuum-assisted breast excision, radiation therapy, or chemotherapy for breast disease. Eighty examinations were performed using each of the four US systems: two ABUS systems and two HHUS systems. For HHUS examinations, four breast radiologists (R1–R4) each examined 20 patients per system. Their breast US experience was as follows: R1, 26 years; R2, 16 years; R3, 19 years; and R4, 26 years. Patients were allocated to ABUS or HHUS according to the physician’s order and, within each modality, were randomly assigned to one of the corresponding ABUS or HHUS systems.
Fig. 1. Flowchart of the study population.
R1–R4 represent the four radiologists included in the study. ABUS, automated breast ultrasound; HHUS, handheld ultrasound.
US Examination
Two ABUS systems and two HHUS systems were used: ABUS-1 (Invenia Premium, GE Healthcare, Chicago, IL, USA; installed in 2025; C16–6 XW linear transducer), ABUS-2 (Invenia R2.0, GE Healthcare; installed in 2021; C15–6 XW linear transducer), HHUS-1 (LOGIQ E10, GE Healthcare; installed in 2024; ML4-20-D linear transducer with a frequency range of 4–20 MHz), and HHUS-2 (Aplio 500, Canon Medical Systems Corporation, Tokyo, Japan; installed in 2015; PLT-1005BT [14L5] 5–14 MHz linear transducer). The HHUS systems differed in installation period, platform configuration, and transducer specifications. Bilateral whole-breast B-mode US was performed using each system. For ABUS examinations, three standardized views, anteroposterior, medial, and lateral, were acquired for both breasts in each patient, with no additional views. For HHUS examinations, bilateral whole-breast B-mode scanning was performed in all patients. Axillary evaluation or Doppler imaging was performed only when requested by the referring physician and was conducted after completion of bilateral whole-breast B-mode scanning. Axillary imaging and any additional Doppler or supplementary examinations were excluded from the present analysis. Therefore, scan time and energy consumption were measured exclusively for bilateral whole-breast B-mode imaging in each patient for both ABUS and HHUS systems to ensure protocol equivalence.
Measurement of Energy Consumption
A power meter (Sentron PAC3220, Siemens Smart Infrastructure, Erlangen, Germany) was custom-built as a detachable box-shaped unit that continuously measured energy consumption at a sampling rate of 1 Hz between the wall outlet and equipment power cable. The power meter setup and corresponding electrical loads are shown in Fig. 2. US system log files were retrieved and correlated with power data using custom MATLAB software (R2022a, MathWorks, Natick, MA, USA). An in-house application synchronized continuous power data with scanner logs over the study period.
Fig. 2. Power meter setup.
A. The internal and external structures of the power meter are shown. B. The integrated power meter is connected to the ultrasound equipment for ABUS-1 (left) and HHUS-1 (right). ABUS, automated breast ultrasound; HHUS, handheld ultrasound.
Energy consumption was measured in three predefined operational modes for each of the four US systems: active mode, defined as actual breast scanning; idle mode, defined as standby or an inactive state while powered on; and off mode, defined as being connected to power but switched off. Examination duration, energy consumption, and GHG emissions were calculated using MATLAB. Examination duration was defined as the total scan time per patient. GHG emissions were estimated using a conversion factor of 0.394 kgCO₂e per kWh. Annual energy consumption and associated GHG emissions were estimated by extrapolating the measured per-examination energy consumption to the institutional annual examination volume for each modality. For extrapolation, the annual ABUS and HHUS examination volumes were assumed to be equally distributed between the two corresponding US systems within each modality. Energy consumption associated with image interpretation, including workstation use and post-processing activities for ABUS and HHUS, was not included in the present analysis. Measurements were restricted to scanner-related energy use during image acquisition.
Statistical Analysis
Average power during active, idle, and off modes was compared among the four US systems. In active mode, examination duration and energy consumption were additionally compared among the four systems and among the four radiologists. The normality of continuous variables was assessed using the Shapiro-Wilk test. For overall group comparisons, one-way analysis of variance was used for normally distributed variables, whereas the Kruskal-Wallis test was used for non-normally distributed variables. When the overall test indicated statistical significance, post hoc pairwise comparisons were performed using the independent-samples t-test or Mann-Whitney U test with Bonferroni correction, as appropriate. To account for clustering due to repeated examinations, mixed-effects models were additionally used for HHUS analyses. In these models, radiologist was included as a fixed effect, and US system was included as a random intercept. All statistical analyses were conducted using two-sided tests. The Bonferroni-adjusted significance threshold was P<0.0083 (0.05/6) for all pairwise comparisons among the four US systems and radiologists. Overall group comparisons were performed using omnibus tests, either one-way analysis of variance or the Kruskal-Wallis test, with statistical significance defined as P<0.05.
Exact P-values were reported throughout the Results section and tables whenever applicable. To improve interpretability and reduce potential bias associated with a single reference group, the tables present overall group comparisons separately from Bonferroni-adjusted post hoc pairwise comparisons. Analyses were performed using R software version 4.4.2 (R Foundation for Statistical Computing, Vienna, Austria).
Results
Overall Energy Use of ABUS and HHUS
The power distribution patterns during B-mode scanning for all four US systems are shown in Fig. 3. Average power in active, idle, and off modes and energy consumption during active scanning for each system are summarized in Tables 1 and 2. In idle mode, average power was significantly lower for ABUS-1 and ABUS-2 (200.01±3.28 W and 230.01±3.28 W, respectively) than for HHUS-1 and HHUS-2 (310.01±3.28 W and 270.01±3.28 W, respectively; overall comparison, P<0.001) (Table 1). Relative to active-mode power, idle-mode power accounted for approximately 65.2% and 63.6% for ABUS-1 and ABUS-2, respectively, and 71.3% and 88.1% for HHUS-1 and HHUS-2, respectively. Among the ABUS systems, ABUS-1 had lower idle-mode power than ABUS-2 (P<0.001); among the HHUS systems, HHUS-2 had lower idle-mode power than HHUS-1 (P<0.001). In off mode, ABUS systems had significantly lower power consumption than HHUS systems. Both ABUS-1 and ABUS-2 consumed 0 W, whereas HHUS-1 and HHUS-2 consumed 50 W and 20 W, corresponding to approximately 11.5% and 6.5% of active-mode power, respectively.
Fig. 3. Energy consumption during ultrasound examinations.
A. Energy consumption during examinations performed using ABUS-1 is shown. B. Energy consumption during examinations performed using ABUS-2 is shown. C. Energy consumption during examinations performed using HHUS-1 is shown. D. Energy consumption during examinations performed using HHUS-2 is shown. ABUS, automated breast ultrasound; HHUS, handheld ultrasound.
Table 1.
Energy use of ABUS and HHUS
| Equipment | Average power (W) | Exam duration (min) in active mode | P-valuea) | Energy consumption (Wh) in active mode | P-valuea) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Active mode | P-valuea) | Idle mode | P-valuea) | Off mode | P-valuea) | |||||
| ABUS-1 | 306.97±7.25 | <0.001 | 200.01±3.28 | <0.001 | 0±0 | NA | 7.29±0.43 | <0.001 | 37.31±2.49 | <0.001 |
| ABUS-2 | 361.37±18.03 | 230.01±3.28 | 0±0 | 7.76±0.81 | 46.77±5.72 | |||||
| HHUS-1 | 434.55±8.12 | 310.01±3.28 | 50.00±0 | 9.64±3.48 | 70.05±25.97 | |||||
| HHUS-2 | 306.48±1.97 | 270.01±3.28 | 20.00±0 | 8.52±3.03 | 43.55±15.64 | |||||
ABUS, automated breast ultrasound; HHUS, handheld ultrasound.
a)P-values represent overall comparisons among the four ultrasound systems. One-way analysis of variance (ANOVA) was used for idle mode power, whereas the Kruskal-Wallis test was used for active mode power, examination duration, and energy consumption. NA indicates that statistical comparison was not applicable because all values within the group were constant.
Table 2.
Bonferroni-adjusted pairwise P-values among the four ultrasound systems
| Equipment | Average power (W) | Exam duration (min) in active mode | Energy consumption (Wh) in active mode | ||
|---|---|---|---|---|---|
| Active mode | Idle mode | Off mode | |||
| ABUS-1 vs. ABUS-2 | <0.001 | <0.001 | >0.99 | <0.001 | <0.001 |
| ABUS-1 vs. HHUS-1 | <0.001 | <0.001 | NA | <0.001 | <0.001 |
| ABUS-1 vs. HHUS-2 | >0.99 | <0.001 | NA | 0.017 | 0.028 |
| ABUS-2 vs. HHUS-1 | <0.001 | <0.001 | NA | 0.002 | <0.001 |
| ABUS-2 vs. HHUS-2 | <0.001 | <0.001 | NA | 0.750 | 0.100 |
| HHUS-1 vs. HHUS-2 | <0.001 | <0.001 | NA | 0.341 | <0.001 |
P-values represent Bonferroni-adjusted post hoc pairwise comparisons among the four ultrasound systems. Statistical significance was defined as P<0.0083 after Bonferroni correction. NA indicates that statistical comparison was not applicable because all values within the group were constant.
ABUS, automated breast ultrasound; HHUS, handheld ultrasound.
In active mode, average power was significantly lower for ABUS-1 (306.97±7.25 W) than for ABUS-2 (361.37±18.03 W, P<0.001) and HHUS-1 (434.55±8.12 W, P<0.001). Average power was also significantly lower for ABUS-2 than for HHUS-1 (361.37±18.03 W vs. 434.55±8.12 W, P<0.001). Average power did not differ significantly between ABUS-1 and HHUS-2 in active mode (306.97±7.25 W vs. 306.48±1.97 W, P>0.99).
Examination duration and energy consumption were further analyzed during active scanning (Table 1). ABUS systems generally had shorter examination durations than HHUS systems. ABUS-1 had a significantly shorter examination duration (7.29±0.43 minutes) than ABUS-2 (7.76±0.81 minutes, P<0.001) and HHUS-1 (9.64±3.48 minutes, P<0.001); however, the difference compared with HHUS-2 (8.52±3.03 minutes) was not significant after Bonferroni correction (P=0.017). Similarly, ABUS-2 had a significantly shorter examination duration than HHUS-1 (P=0.002). Examination duration did not differ significantly between ABUS-2 and HHUS-2 (P=0.750), and no significant difference was observed between HHUS-1 and HHUS-2 (P=0.341).
Energy consumption during active scanning was significantly lower for ABUS-1 (37.31±2.49 Wh) than for ABUS-2 (46.77±5.72 Wh, P<0.001) and HHUS-1 (70.05±25.97 Wh, P<0.001). However, the difference compared with HHUS-2 (43.55±15.64 Wh) did not remain significant after Bonferroni correction (P=0.028). Notably, ABUS-1 consumed 47% less energy than HHUS-1. ABUS-2 consumed significantly less energy than HHUS-1 (46.77±5.72 Wh vs. 70.05±25.97 Wh, P<0.001), but energy consumption did not differ significantly between ABUS-2 and HHUS-2 (46.77±5.72 Wh vs. 43.55±15.64 Wh, P=0.100).
Energy consumption and GHG emissions per breast US examination for each system, together with extrapolated annual energy consumption and GHG emissions based on institutional annual examination volume, are summarized in Table 3. From January to December 2025, 3,958 ABUS examinations and 7,577 HHUS examinations were performed at the authors’ affiliated institution. Within each modality, ABUS-1 had lower annual energy consumption and GHG emissions than ABUS-2, and HHUS-2 had lower values than HHUS-1 (P<0.001 for both comparisons). Annual energy consumption was 147.67±0.16 kWh for ABUS-1, 185.09±0.36 kWh for ABUS-2, 530.97±2.26 kWh for HHUS-1, and 329.47±1.36 kWh for HHUS-2, with corresponding annual GHG emissions of 58.18±0.06, 72.93±0.14, 209.20±0.89, and 129.87±0.54 kgCO2e, respectively.
Table 3.
Energy consumption per examination and estimated annual energy use of ABUS and HHUS systems
| Equipment | Energy consumption | GHG emissions | ||||
|---|---|---|---|---|---|---|
| Per examination (Wh) | Annual (extrapolated, kWh)a) | P-valueb) | Per examination (kgCO2e) | Annual (extrapolated, kgCO2e)a) | P-valueb) | |
| ABUS-1 | 37.31±2.49 | 147.67±0.16 | - | 0.01±0.00 | 58.18±0.06 | - |
| ABUS-2 | 46.77±5.72 | 185.09±0.36 | <0.001 | 0.02±0.00 | 72.93±0.14 | <0.001 |
| HHUS-1 | 70.05±25.97 | 530.97±2.26 | - | 0.03±0.01 | 209.20±0.89 | - |
| HHUS-2 | 43.55±15.64 | 329.47±1.36 | <0.001 | 0.02±0.01 | 129.87±0.54 | <0.001 |
ABUS, automated breast ultrasound; HHUS, handheld ultrasound; GHG, greenhouse gas.
a)Annual values were calculated by extrapolating per-examination measurements based on the institutional annual volume of breast ultrasonography examinations in 2025 (3,958 for ABUS and 7,577 for HHUS), which was equally distributed across the corresponding systems. b)P-values represent within-modality comparisons between ABUS-1 and ABUS-2, and between HHUS-1 and HHUS-2.
Comparison of Energy Use between Radiologists
Energy use during HHUS examinations by different radiologists is summarized in Tables 4 and 5. Pairwise comparisons between ABUS and HHUS systems for each radiologist are presented in Supplementary Table 1. Although HHUS-1 and HHUS-2 had similar average power in active mode, examination duration varied among radiologists, resulting in differences in energy consumption. Average power did not differ significantly among radiologists for either HHUS system (HHUS-1, P=0.700; HHUS-2, P=0.294). Across both HHUS systems, R1 had the longest examination duration, and R2 had the shortest. Examination duration differed significantly between R1 and R2 for both HHUS systems: 11.12±2.86 minutes vs. 7.49±2.59 minutes for HHUS-1 (P=0.005) and 9.56±2.06 minutes vs. 7.25±2.70 minutes for HHUS-2 (P=0.006). Energy consumption also differed significantly between R1 and R2 for both HHUS systems: 81.44±21.85 Wh vs. 54.56±19.25 Wh for HHUS-1 (P=0.001) and 48.87±10.63 Wh vs. 37.05±13.95 Wh for HHUS-2 (P=0.003).
Table 4.
Energy use according to radiologist during breast HHUS examinations
| Equipment | Radiologist | Average power (W) | P-valuea) | Examination duration (min) | P-valuea) | Energy consumption (Wh) | P-valuea) |
|---|---|---|---|---|---|---|---|
| HHUS-1 | R1 | 438.76±8.20 | 0.700 | 11.12±2.86 | 0.002 | 81.44±21.85 | 0.001 |
| R2 | 436.15±5.72 | 7.49±2.59 | 54.56±19.25 | ||||
| R3 | 432.14±9.98 | 9.84±4.45 | 71.17±33.20 | ||||
| R4 | 431.14±5.92 | 10.14±2.87 | 73.01±21.34 | ||||
| HHUS-2 | R1 | 306.45±1.92 | 0.294 | 9.56±2.06 | 0.034 | 48.87±10.63 | 0.035 |
| R2 | 306.26±1.73 | 7.25±2.70 | 37.05±13.95 | ||||
| R3 | 306.10±2.39 | 8.46±3.68 | 43.22±19.07 | ||||
| R4 | 307.13±1.75 | 8.80±3.18 | 45.04±16.42 |
R1–R4 represent the four radiologists included in the study.
HHUS, handheld ultrasound.
a)P-values represent overall comparisons among the four radiologists within each system. One-way analysis of variance (ANOVA) was used for average power and examination duration in HHUS-1, and for average power in HHUS-2, whereas the Kruskal-Wallis test was used for energy consumption in HHUS-1, and for examination duration and energy consumption in HHUS-2.
Table 5.
Bonferroni-adjusted pairwise P-values among radiologists during breast HHUS examinations
| Equipment | Radiologist comparison | Average power (W) | Examination duration (min) | Energy consumption (Wh) |
|---|---|---|---|---|
| HHUS-1 | R1 vs. R2 | 0.653 | 0.005 | 0.001 |
| R1 vs. R3 | 0.118 | 1.000 | 0.405 | |
| R1 vs. R4 | 0.010 | 0.159 | 1.000 | |
| R2 vs. R3 | 0.414 | 1.000 | 0.852 | |
| R2 vs. R4 | 0.046 | 0.075 | 0.031 | |
| R3 vs. R4 | 0.980 | 1.000 | 1.000 | |
| HHUS-2 | R1 vs. R2 | 0.573 | 0.006 | 0.003 |
| R1 vs. R3 | 0.681 | 0.407 | 0.380 | |
| R1 vs. R4 | 0.092 | 0.642 | 0.648 | |
| R2 vs. R3 | 0.237 | 1.000 | 1.000 | |
| R2 vs. R4 | 0.754 | 0.756 | 0.726 | |
| R3 vs. R4 | 0.146 | 1.000 | 1.000 |
R1–R4 represent the four radiologists included in the study.
HHUS, handheld ultrasound.
P-values represent Bonferroni-adjusted post hoc pairwise comparisons among radiologists (R1–R4) within each HHUS system. Statistical significance was defined as P<0.0083 after Bonferroni correction.
Comparisons between ABUS and HHUS systems showed that examination duration was shorter for ABUS than for HHUS, although statistical significance varied by radiologist. For both ABUS-1 and ABUS-2, examination duration was significantly shorter than that of HHUS-1 when performed by R1 and R4 (P<0.001). In addition, ABUS-1 had a shorter examination duration than HHUS-2 when performed by R1 (P<0.001), but the difference for R4 did not remain significant after Bonferroni correction (P=0.009). No significant differences were observed between ABUS-2 and HHUS-2 after Bonferroni correction. Energy consumption during examinations was significantly lower for both ABUS-1 (37.31±2.49 Wh) and ABUS-2 (46.77±5.72 Wh) than for HHUS-1 across all radiologists (ABUS-1: R1, P<0.001; R2, P<0.001; R3, P<0.001; R4, P<0.001; ABUS-2: R1, P<0.001; R2, P=0.002; R3, P=0.001; R4, P<0.001). ABUS-1 also showed lower energy consumption than HHUS-2 when performed by R1 (P<0.001). In contrast, differences between ABUS-2 and HHUS-2 were inconsistent, with statistical significance observed only when HHUS-2 was performed by R2 (P=0.006), but not for the other radiologists. Additional mixed-effects model analyses accounting for repeated examinations yielded results consistent with those of the primary analyses.
Discussion
This study evaluated the energy consumption of four breast US systems, including two ABUS systems (ABUS-1 and ABUS-2) and two HHUS systems (HHUS-1 and HHUS-2), during routine clinical practice in the radiology department of a single tertiary hospital. Few studies have examined energy consumption in breast US, and data specific to ABUS systems remain limited. In idle and off modes, ABUS systems had significantly lower average power consumption than HHUS systems. During active scanning, examination duration was shorter for ABUS than for HHUS, and the recently installed ABUS-1 had the shortest examination time. Consequently, energy consumption during active scanning was lowest for ABUS-1, which used approximately 47% less energy than HHUS-1. In addition, both ABUS systems consistently showed significantly lower energy consumption than HHUS-1 across all four radiologists. Overall, ABUS systems showed lower energy use in idle and off modes and similar or lower energy consumption during active scanning compared with HHUS systems. These findings suggest that ABUS systems may offer advantages in operational efficiency and energy use during routine whole-breast US practice.
Whole-breast US is recognized as a useful adjunct screening tool for women with heterogeneously or extremely dense breast tissue and for women at high lifetime risk of breast cancer (≥20%) who are not candidates for breast MRI or have limited access to breast MRI, according to the updated 2025 BI-RADS recommendations [14]. Several large multi-institutional and prospective trials, including ACRIN 6666, J-START, and ASTOUND, have shown that supplemental breast US improves the detection of small, node-negative invasive breast cancers compared with mammography alone in women with dense breast tissue [23–25]. Whole-breast US can be performed using either HHUS or ABUS. ABUS systems allow multiplanar image reconstruction, which may improve lesion characterization. Coronal reconstructed images, in particular, can enhance visualization of architectural distortion associated with malignancy, which appears as radiating hypoechoic lines perpendicular to and converging on a central hypoechoic mass, as described in the 2025 BI-RADS Atlas [14]. In this study, we evaluated energy consumption during whole-breast US examinations in routine clinical practice and compared energy use between HHUS and ABUS systems. Additional energy consumption related to axillary imaging, Doppler imaging, or shear-wave elastography was not assessed; the analysis was limited to B-mode imaging for both HHUS and ABUS systems.
In idle mode, defined as the standby or inactive state, power draw remained highly stable over prolonged standby periods, resulting in minimal variability and nearly identical standard deviation values across systems. This finding likely reflects the intrinsic technical stability of standby power consumption rather than true differences in variability between systems. In this mode, all ABUS and HHUS systems consumed a substantial proportion of active-mode power, approximately 60%–90%. In off mode, ABUS systems consumed no power, whereas HHUS systems continued to consume residual power. The findings for HHUS systems are consistent with those of previous studies that evaluated US energy consumption, although those studies were not specific to breast imaging. Mujkic et al. [10] and Roletto et al. [26] reported substantial energy consumption during idle periods and emphasized several cost-effective strategies for reducing energy use, including switching off equipment after examinations are completed on weekdays and weekends, improving scanner scheduling efficiency to minimize idle time, and selecting lower-energy imaging examinations without compromising clinical appropriateness. Mujkic et al. [10] also reported that, in off mode, nine different HHUS machines continued to consume average power of 0.45–56 W during the shutdown phase; the present findings are consistent with that report. These observations suggest that complete disconnection from the power supply, such as unplugging systems after completion of daily examinations, may be necessary to minimize residual energy consumption in off mode. Overall, ABUS systems showed clear advantages over HHUS systems in both off and idle modes with respect to energy consumption in this study.
ABUS-1 had significantly lower average power, shorter examination duration, and lower energy consumption during active scanning than the other three US systems. ABUS-2 also had lower average power, shorter examination duration, and lower energy consumption than HHUS-1, although these differences were not statistically significant when ABUS-2 was compared with HHUS-2. Previous studies have reported that acquisition time is more consistent with ABUS than with HHUS [27]. ABUS examinations follow standardized scanning protocols in three orthogonal directions, resulting in relatively fixed examination times, whereas HHUS examination duration may vary according to lesion size, lesion number, and operator expertise. This consistency in ABUS scanning time may improve workflow efficiency and support more efficient use of US equipment.
This study found that ABUS had significantly lower average power in idle and off modes, consistently shorter examination durations, and similar or lower energy consumption during active scanning compared with HHUS. These findings suggest that ABUS may offer advantages for both operational efficiency and energy sustainability. Given the increasing use of breast US, modality-specific differences in energy consumption may cumulatively affect the overall carbon footprint of healthcare institutions. When considered alongside established energy-saving practices in US, such as using the freeze function between scans, switching devices to off mode after daily use, and adopting energy-efficient hardware and software, the lower energy demand associated with ABUS supports consideration of energy use in imaging protocol selection and equipment planning.
To contextualize the magnitude of energy consumption and associated carbon emissions, extrapolated annual values were compared with average household electricity use in Seoul. In 2023, the mean monthly electricity consumption per household in Seoul was approximately 239 kWh [28]. Based on this benchmark, the annual energy consumption of ABUS-1 (147 kWh) corresponds to approximately 0.6 months of electricity use for a single household, whereas that of HHUS-1 (530 kWh) corresponds to approximately 2.2 months of household electricity consumption. GHG emissions were estimated using a standardized electricity emission factor; therefore, the resulting GHG values represent emissions associated with an equivalent level of household electricity consumption over the same period.
This study has several limitations. First, it was conducted at a single tertiary care center, which may limit the generalizability of the findings. Second, it assessed only the electrical energy consumption of US scanners during examinations and did not perform a comprehensive life cycle assessment that included equipment manufacturing, consumables, imaging data storage and transmission, or energy use related to image interpretation and workstation activities. Frederick-Dyer et al. [11] reported that direct energy consumption of US equipment accounts for approximately 3% of total carbon dioxide emissions, suggesting that a more comprehensive life cycle-based analysis is needed to fully evaluate the environmental impact and energy sustainability of breast US. Third, because annual examination volumes differed between ABUS and HHUS at the authors’ affiliated institution, extrapolated annual energy-consumption values were intended for within-modality comparisons rather than direct comparisons between modalities. Fourth, energy measurements were performed sequentially using a single power meter, which may have introduced a temporal or learning effect because radiologists might have become more familiar with the standardized study protocol over time. In addition, differences in system generation, platform configuration, or user interface between HHUS-1 and HHUS-2 may have influenced workflow efficiency and examination duration. Future studies using multiple power meters to enable simultaneous measurements across different US systems would further minimize such potential bias. Despite these limitations, this study is, to the authors’ knowledge, the first to directly measure energy consumption during breast US examinations in routine clinical practice and provides baseline data for future investigations of sustainable US imaging practices.
In conclusion, compared with HHUS, ABUS had lower power consumption in idle and off modes and similar or lower energy consumption during active scanning. When clinically appropriate, preferential use of ABUS over HHUS, together with optimization of US workflows, particularly minimization of idle time, may improve environmental sustainability while preserving clinical utility. Further studies incorporating comprehensive life cycle assessments and diagnostic performance analyses are warranted to compare the environmental impact of ABUS and HHUS more fully.
Key points
Automated breast ultrasound (ABUS) had lower power use in idle and off modes and similar or lower energy consumption during active scanning than handheld ultrasound. Standardized ABUS examinations provide shorter, more consistent scan times, which support workflow efficiency. Preferential use of ABUS may promote sustainable whole-breast ultrasound practice without compromising clinical utility.
Footnotes
Author Contributions
Conceptualization: Seo BK, Choi S. Data acquisition: Lee JY, Seo BK, Bae MS, Moon Y. Data analysis or interpretation: Lee JT, Choi H, Yoon Y. Drafting of the manuscript: Lee JY, Lee JT, Seo BK, Yoon Y, Choi S. Critical revision of the manuscript: Lee JY, Lee JT, Seo BK, Bae MS, Moon Y, Choi H, Choi S. Approval of the final version of the manuscript: all authors.
Conflict of Interest
The devices used in this study were manufactured by GE Healthcare (Invenia Premium, Invenia R2.0, LOGIQ E10) and Canon Medical Systems Corporation (Aplio 500). These systems are part of the standard clinical equipment at the authors’ affiliated institution and were selected based on routine clinical availability. No financial support, equipment loans, speaker fees, consulting fees, or any other form of compensation was received from GE Healthcare or Canon Medical Systems Corporation in relation to this study. The authors declare no other conflicts of interest.
Acknowledgments
This study was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Korean government (RS-2024-00347290).
Supplementary Material
Sample size determination (https://doi.org/10.14366/usg.26043).
Bonferroni-adjusted pairwise P-values for examination duration and energy consumption between ABUS and HHUS systems according to radiologist (https://doi.org/10.14366/usg.26043).
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Sample size determination (https://doi.org/10.14366/usg.26043).
Bonferroni-adjusted pairwise P-values for examination duration and energy consumption between ABUS and HHUS systems according to radiologist (https://doi.org/10.14366/usg.26043).