Low-dose Protocol Research Articles

Sex-specific GABAergic microcircuits that switch vulnerability into resilience to stress and reverse the effects of chronic stress exposure.

Clinical and preclinical studies have identified somatostatin (SST)-positive interneurons as critical elements that regulate the vulnerability to stress-related psychiatric disorders. Conversely, disinhibition of SST neurons in mice results in resilience to the behavioral effects of chronic stress. Here, we established a low-dose chronic chemogenetic protocol to map these changes in positively and negatively motivated behaviors to specific brain regions. AAV-hM3Dq-mediated chronic activation of SST neurons in the prelimbic cortex (PLC) had antidepressant drug-like effects on anxiety- and anhedonia-like motivated behaviors in male but not female mice. Analogous manipulation of the ventral hippocampus (vHPC) had such effects in female but not male mice. Moreover, the activation of SST neurons in the PLC of male mice and the vHPC of female mice resulted in stress resilience. Activation of SST neurons in the PLC reversed prior chronic stress-induced defects in motivated behavior in males but was ineffective in females. Conversely, activation of SST neurons in the vHPC reversed chronic stress-induced behavioral alterations in females but not males. Quantitation of c-Fos+ and FosB+ neurons in chronic stress-exposed mice revealed that chronic activation of SST neurons leads to a paradoxical increase in pyramidal cell activity. Collectively, these data demonstrate that GABAergic microcircuits driven by dendrite targeting interneurons enable sex- and brain-region-specific neural plasticity that promotes stress resilience and reverses stress-induced anxiety- and anhedonia-like motivated behavior. The data provide a rationale for the lack of antidepressant efficacy of benzodiazepines and superior efficacy of dendrite-targeting, low-potency GABAA receptor agonists, independent of sex and despite striking sex differences in the relevant brain substrates.

Tube current reduction and iterative image reconstruction for computed tomography myelography.

This study aimed to systematically evaluate the impact of a low-dose (LD) protocol using tube current reduction on image quality, the confidence for intervention planning and guidance, and diagnostic yield for computed tomography (CT)myelography. We retrospectively analyzed 68 patients who underwent CT myelography, with 34 investigations performed with a standard-dose (SD) and 34 investigations performed with a LD protocol (using tube current reduction). The different scans were matched considering variables such as sex, age, presence of spinal instrumentation, and body diameter. All images were evaluated by two readers (R1 and R2) using Likert scales. Image noise was measured using attenuation values of paraspinal muscle tissue. Images were reconstructed with model-based iterative reconstruction (post-myelography diagnostic scans) or hybrid reconstruction (planning, periprocedural, and diagnostic scans). Image quality, overall artifacts, image contrast, and confidence for planning or intervention guidance were rated good to perfect for both SD and LD scans according to evaluations of both readers. Inter-reader agreement was good to very good for the images from intervention planning (κ ≥ 0.80) as well as for intervention guidance (κ ≥ 0.77), as well as for diagnostic scans (κ ≥ 0.85). Image noise was similar between SD and LD scans performed for planning of the interventional procedures (model-based iterative reconstruction: SD 45.37 ± 7.29 HU vs. LD 45.17 ± 9.12 HU; hybrid reconstruction: SD 46.05 ± 7.43 HU vs. LD 45.05 ± 8.69 HU; p > 0.05). The volume-weighted CT dose index (CTDIvol) and size-specific dose estimate (SSDE) were significantly lower for the planning scans as well as the periprocedural scans when using the LD protocol as compared to the SD protocol (p < 0.05). In conclusion,implementation of a LD protocol with tube current reduction for CT myelography is a feasible option to reduce radiation exposure, especially when combined with iterative image reconstruction. In our study, LD imaging did not have a relevant negative impact on image quality, confidence for intervention planning or guidance, or diagnostic certainty for CT myelography.

The Effect of Low-Dose CT Protocols on Shoulder Model-Based Tracking accuracy Using Biplane Videoradiography.

Model-based tracking is being increasingly used to quantify shoulder kinematics and typically employs computed tomography (CT) to create the 3D bone volumes, which adds to the total radiation exposure. Lower-dose CT protocols may be possible given the contrast between bone and the surrounding soft tissues. The purpose of this study was to describe the dose-accuracy tradeoff between low-dose CT scans and the kinematic tracking accuracy of the humerus, scapula, and clavicle when tracked using an intensity-based registration algorithm. Three fresh-frozen cadavers consisting of the torso and bilateral shoulders were tested. The CT protocols investigated included a full-dose protocol and 4 experimental low-dose protocols that modulated x-raytube current and peak voltage. Bead-based tracking (i.e., radiostereometric analysis) served as the reference standard to which model-based tracking results were compared. Accuracy was described in terms of both segmental (humerus, scapula, and clavicle) and joint (glenohumeral, acromioclavicular) kinematics using root-mean-square (RMSE), bias, precision, and worst-case errors. The low-dose CT scans resulted in an average dose reduction of 70.6-92.8%. RMSEs tended to increase as CT dose decreased with average glenohumeral errors increasing from 0.5° and 0.6 mm to 0.6° and 0.6 mm between the highest and lowest-dose protocols, and average acromioclavicular errors increasing from 0.6° and 0.8 mm to 0.7° and 0.9 mm. However, the difference in joint kinematic errors between the highest and lowest-dose CT scanning protocols was generally small (≤0.3°, ≤ 0.1 mm). It is possible to substantially reduce the CT dose associated with shoulder motion analysis using biplane videoradiography without significantly impacting data fidelity.

Low-Dose Cone-Beam Computed Tomography in Swedish Pediatric Patients With Alveolar Clefts Following Alveolar Bone Grafting-A Clinical Study.

The aim of this study was to investigate whether a low-dose cone-beam computed tomography (CBCT) protocol provides diagnostically acceptable image quality for assessing bone healing after alveolar bone grafting. The study cohort comprised 11 patients (aged 7-14 years) with orofacial clefts who had undergone alveolar bone grafting at Skåne University Hospital in Malmö, Sweden. During the postsurgical follow-up at 6 months, each patient was assessed twice: once with a standard-dose CBCT protocol and once with a low-dose CBCT protocol, which in total corresponds to one CBCT examination made with the exposure settings recommended by the manufacturer. Among others, the assessed parameters included subjective image quality, as well as bone graft height, thickness, and integration. No significant differences were found between the standard- and low-dose protocols for most parameters (p > 0.05). Exceptions included subjective image quality (one observer, p = 0.05) and confidence levels during the assessment (three observers, p = 0.01, 0.01, 0.02). The low-dose protocol yielded adequate image quality for postoperative CBCT healing assessment in patients who have undergone alveolar bone grafting. However, the confidence level of observers during the assessment with the low-dose protocol was reduced. This study is registered on ClinicalTrials.gov (NCT06395077). This study is registered on ClinicalTrials.gov (NCT06395077).

Safety, efficacy, and side effects of sodium fluorescein-aided resection of glioblastoma: a quasi-experimental study.

The use of fluorescein sodium (FS) as a surgical adjunct in glioblastoma resection has shown promise in improving tumor visualization and resection outcomes. This study aimed to evaluate the safety, efficacy, and side effects of FS-aided resection in patients with glioblastoma. This is a prospective, single-center cohort study conducted at Ibrahim Cardiac Hospital and Research Institute from September 2021 to November 2023. Twelve patients with histologically confirmed glioblastoma underwent FS-guided resection. All participants received an intravenous dose of FS (5mg/kg body weight) ~30min before surgery. The study follows a quasi-experimental design, focusing on the outcomes of FS-aided surgery without a control group. Patients were selected based on specific inclusion and exclusion criteria, and all surgeries were performed by a single experienced neurosurgeon. The extent of tumor resection was classified as gross total resection (GTR), near-total resection (NTR), or partial resection (PR). Gross total resection (GTR) was achieved in 66.6% of patients, near total resection (NTR) in 16.6%, and subtotal resection (STR) in 16.6%. No significant adverse effects were observed except for a single case of postoperative seizure, which was managed without long-term consequences. All patients showed normal liver and kidney function tests postoperatively. The low-dose FS protocol demonstrated both a high rate of GTR and a favorable safety profile, with only minor, transient side effects such as temporary yellow discoloration of the skin, sclera, and urine. No severe or long-term complications related to FS were observed during the follow-up period, which had a median duration of 13.4 months. FS appears to be a safe and effective aid in glioblastoma resection, achieving high rates of GTR with minimal side effects. The findings suggest that FS, particularly at a low dose, is a viable, cost-effective alternative to other fluorescent markers, especially in settings where resource constraints may limit the use of more expensive options like 5-ALA.

Ultra-High-Resolution Photon-Counting Detector CT Benefits Visualization of Abdominal Arteries: A Comparison to Standard-Reconstruction.

This study aimedto investigate the potential benefit of ultra-high-resolution (UHR) photon-counting detector CT (PCD-CT) angiography in visualization of abdominal arteries in comparison to standard-reconstruction (SR) images of virtual monoenergetic images (VMI) at low kiloelectron volt (keV).We prospectively included 47 and 47 participants to undergo contrast-enhanced abdominal CT scans within UHR mode on a PCD-CT systemusing full-dose (FD) and low-dose (LD) protocols, respectively. The data were reconstructed into six series of images: FD_UHR_Br48, FD_UHR_Bv56, FD_UHR_Bv60, FD_SR_Bv40, LD_UHR_Bv48, and LD_SR_Bv40. The UHR reconstructions were performed with three kernels (Bv48, Bv56, and Bv60) within 0.2mm. The SR were virtual monoenergetic imaging reconstruction with Bv40 kernel at 40-keV within 1mm. Each series of axial images were reconstructed into coronal and volume-rendered images. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of seven arteries were measured. Three radiologists assessed the image quality, and visibility of nine arteries on all the images.SNR and CNR values of SR images were significantly higher than those of UHR images (P < 0.001). The SR images have higher ratings in image noise (P < 0.001), but the FD_UHR_Bv56 and FD_UHR_Bv60 images has higher rating in vessel sharpness (P < 0.001). The overall quality was not significantly different among FD_VMI_40keV, LD_VMI_40keV, FD_UHR_Bv48, and LD_UHR_Bv48 images (P > 0.05) but higher than those of FD_UHR_Bv56 and FD_UHR_Bv60 images (P < 0.001). There is no significant difference of nine abdominal arteries among six series of images of axial, coronal and volume-rendered images (P > 0.05).To conclude, 1-mm SR image of VMI at 40-keV is superior to 0.2-mm UHR regardless of which kernel is used to visualize abdominal arteries, while 0.2-mm UHR image using a relatively smooth kernel may allow similar image quality and artery visibility when thinner slice image is warranted.

Adverse Pregnancy Outcomes and Chronic Hypertension in the Era of Prevention: A Contemporary, Retrospective Cohort Study Using Data from the National Inpatient Sample Database.

Chronic hypertension is a known risk factor for the development of preeclampsia and obstetrical morbidity. However, recent risk estimates, particularly in the era of use of low-dose acetylsalicylic acid for preeclampsia prevention, are lacking. This study aimed to estimate the association between chronic hypertension and preeclampsia and other adverse pregnancy outcomes in a contemporary cohort of births spanning the period, since the introduction of a low-dose acetylsalicylic acid protocol. The secondary outcome was to estimate trends in preeclampsia and preterm birth among patients with chronic hypertension during the study period. A retrospective, population-based cohort study was conducted using the National Inpatient Sample Database to identify individuals discharged from hospitals in the United States following obstetrical delivery from 2014 to 2019. Pregnancies complicated by chronic hypertension were identified using ICD 9/10 (International Classification of Diseases 9th and 10th editions) codes. Multivariable logistic regression models were used to estimate the adjusted odds ratios for the association between chronic hypertension and adverse pregnancy outcomes compared with pregnancies not complicated by chronic hypertension. Temporal trends in preeclampsia and preterm birth among patients with chronic hypertension were estimated over the study period. Among 4,451,667 obstetrical delivery-related admissions, 139,556 (3.1%) included pregnancies complicated by chronic hypertension. Of these, 27,146 (19.4%) admissions included pregnancies with superimposed preeclampsia, compared with 222,351 (5.2%) of admissions that included pregnancies with preeclampsia without prior diagnosis of chronic hypertension. Pregnancies complicated by chronic hypertension were associated with 3.29 times the odds of preeclampsia compared with pregnancies without chronic hypertension (95% confidence interval: 3.22-3.36), but the odds of preeclampsia (p-value for linear trend <0.0001) and preterm birth (p-value for linear trend = 0.0001) in this subgroup decreased over the study period. While the odds of preeclampsia are increased among pregnancies complicated by chronic hypertension, the odds of preeclampsia in this population have decreased over time. · Pregnancies complicated by chronic hypertension are at significantly higher odds of preeclampsia.. · Recent guidelines have recommended low-dose acetylsalicylic acid for preeclampsia prevention in these pregnancies.. · In a nationwide cohort, the odds of preeclampsia among these pregnancies are decreasing over time..

Performance of Lung-Nodule Computer-Aided Detection Systems on Standard-Dose and Low-Dose Pediatric CT Scans: An Intraindividual Comparison.

Background: When applying lung-nodule computer-aided detection (CAD) systems for pediatric CT, performance may be degraded on low-dose scans due to increased image noise. Objective: To conduct an intraindividual comparison of the performance for lung nodule detection of two CAD systems trained using adult data between low-dose and standard-dose pediatric chest CT scans. Methods: This retrospective study included 73 patients (32 female, 41 male; mean age, 14.7 years; age range, 4-20 years) who underwent both clinical standard-dose and investigational low-dose chest CT examinations within the same encounter from November 30, 2018 to August 31, 2020 as part of an earlier prospective study. Fellowship-trained pediatric radiologists annotated lung nodules to serve as the reference standard. Both CT scans were processed using two publicly available lung-nodule CAD systems previously trained using adult data: FlyerScan and Medical Open Network for Artificial Intelligence (MONAI). The systems' sensitivities for nodules measuring 3-30 mm (n=247) were calculated when operating at a fixed frequency of two false-positives per scan. Results: FlyerScan exhibited detection sensitivities of 76.9% (190/247; 95% CI: 73.3-80.8%) on standard-dose scans and 66.8% (165/247; 95% CI: 62.6-71.5) on low-dose scans. MONAI exhibited detection sensitivities of 67.6% (167/247, 95% CI: 61.5-72.1) on standard-dose scans and 62.3% (154/247, 95% CI: 56.1-66.5%) on low-dose scans. The number of detected nodules for standard-dose versus low-dose scans for 3-mm nodules was 33 versus 24 (FlyerScan) and 16 versus 13 (MONAI), 4-mm nodules was 46 versus 42 (FlyerScan) and 39 versus 30 (MONAI), 5-mm nodules was 38 versus 33 (FlyerScan) and 32 versus 31 (MONAI), and 6-mm nodules was 27 versus 20 (FlyerScan) and 24 versus 24 (MONAI). For nodules measuring ≥7 mm, detection did not show a consistent pattern between standard-dose and low-dose scans for either system. Conclusions: Two lung-nodule CAD systems demonstrated decreased sensitivity on low-dose versus standard-dose pediatric CT scans performed in the same patients. The reduced detection at low dose was overall more pronounced for nodules measuring less than 5 mm. Clinical Impact: Caution is needed when using low-dose CT protocols in combination with CAD systems to help detect small lung nodules in pediatric patients.

Comparison between the intraoperative CT O-arm and C-arm related to radiation dose and accuracy in scoliosis surgery: A review study

Pedicle screw placement is a vital scoliosis therapy operation that aims to address spinal abnormalities while avoiding consequences including neurological damage caused by misplaced screws. Accurate imaging is required for precise screw insertion, with intraoperative CT (O-arm) and fluoroscopy (C-arm) being the principal modalities used. This review assesses various modalities based on their radiation dosages and accuracy. It comprises research published between 2012 and 2020 that evaluates both effective dose and accuracy for pediatric and adult patients. According to the review, the O-arm outperforms the C-arm in terms of accuracy, resulting in shorter procedure times for both pediatric and adult patients. The O-arm's sophisticated 3-D imaging capacity enhances screw insertion accuracy, reducing the likelihood of problems and the need for additional procedures. Furthermore, using pediatric low-dose protocols and techniques like the Detachable Pedicle Marker and Probe (DPMPs) with pulsed fluoroscopy can reduce radiation exposure while still ensuring precise screw placement. The review suggests that the O-arm has considerable advantages over the C-arm, such as improved image quality and lower radiation risk. This leads to enhanced patient safety and procedural outcomes. Overall, the O-arm's capacity to produce high-quality 3-D pictures makes it an invaluable tool in pedicle screw insertion, resulting in more accurate surgical outcomes and reducing the risk of problems associated with spinal deformity repairs.

Bloodless lung transplantation: Comparison between 2 central venoarterial extracorporeal membrane oxygenation anticoagulation strategies and their impact on lung transplant outcomes

ObjectiveTo report differences between 2 anticoagulation protocols during venoarterial extracorporeal membrane oxygenation (VA-ECMO) intraoperative support and their effects on outcomes after lung transplantation. MethodsWe performed a retrospective analysis of patients undergoing double-lung transplantation with intraoperative VA-ECMO from January 1, 2016, to December 30, 2023. Two distinct anticoagulation protocols were in place during this period. One included targeted activated clotting time >180 seconds at all times with protamine reversal after decannulation. The second included 75 units per kilogram of heparin at the time of cannulation with no redosing plus a tranexamic acid infusion after ECMO initiation. ResultsA total of 116 patients (46 low heparin, 70 standard) were included in the analysis. Cannulation strategies and ECMO circuit were equivalent between the groups. The low-dose heparin protocol group had a shorter surgical time (7.28 hours vs 8.53 hours, P < .001) and required significantly less intraoperative packed red blood cells (median 0 vs 4.37 units, P < .001), fresh-frozen plasma (median 0 vs 2 units, P < .001), platelets (median 0 vs 1 units, P < .001), cryoprecipitate (median 0 vs 0 units, P < .001), and total blood products (median 0 vs 9 units, P < .001) compared with the standard group. There were no differences in rates of deep vein thrombosis (P = .13), airway dehiscence (P > .99), pneumonia (P = .38), or acute kidney injury requiring renal-replacement therapy (P = .59). There was no difference in rates of severe grade 3 primary graft dysfunction at 72 hours after transplant (P = .42). ConclusionsOur low-dose heparin VA-ECMO protocol for intraoperative support during lung transplantation led to a significant reduction of blood product use. Although this did not translate to a reduced rates of grade 3 primary graft dysfunction, the low-dose heparin protocol was associated with similar postoperative outcomes.

A Multidisciplinary Assessment of Standard Low Dose Versus Ultra-low Dose Chest CT Scans for Pectus Excavatum Imaging

AimEvaluation of ultra-low dose chest CT imaging for the assessment of pectus excavatum severity as determined by pediatric radiologists and pediatric surgeons using Haller (HI) and Correction indices (CI). MethodsA single institution, prospective evaluation of patients being evaluated for pectus excavatum were scanned with a standard low-dose chest CT protocol (CARE) followed by a consecutive ultra-low dose CT scan (ULTRA). 3 surgeons and 4 radiologists were instructed to determine HI and CI in each series. The Intraclass Correlation Coefficient (ICC) was used to calculate the agreement level between CARE and ULTRA. Bland–Altman (BA) and scatter plots were also performed to determine bias of each approach. Results32 patients had CARE and ULTRA consecutively. The ICC for HI demonstrated good reliability with a value of 0.89 and excellent reliability for CI with a value of 0.91. The reliability for HI was greater in the surgeon group (0.89) compared to the radiologist group (0.88). The reliability for CI was greater in the radiologist group (0.92) compared to the surgeon group (0.90). The Bland Altman plots for the HI and CI demonstrate no consistent bias for CARE or ULTRA approach when evaluating HI and CI. ConclusionUltra-low dose CT scan imaging compared to standard low-dose CT appears to be a reliable alternative for evaluating PE severity as assessed by HI and CI. This work supports the evaluation and potential development of a standardized CT imaging protocol capable of reducing radiation exposure without sacrificing imaging for PE patients. Level of Evidence2.

Comprehensive risk management and safety strategies in radiation use in medical imaging

Radiation use in medical imaging, while essential for accurate diagnosis and treatment planning, poses inherent risks that require comprehensive risk management and safety strategies. This review discusses the critical aspects of managing these risks in clinical settings, focusing on patient safety, staff protection, and environmental considerations. A major challenge in medical imaging is balancing the diagnostic benefits of radiation against potential harms, particularly in sensitive populations such as children and pregnant women. Comprehensive risk management involves implementing dose optimization techniques, such as using low-dose imaging protocols and advanced technologies like iterative reconstruction and artificial intelligence (AI) algorithms, which enhance image quality while minimizing exposure. Additionally, ensuring the safety of healthcare staff is paramount. This requires adherence to strict safety protocols, including the use of personal protective equipment (PPE), regular monitoring of radiation levels, and continuous education on safe radiation practices. Institutional policies must also address the proper maintenance and calibration of imaging equipment to prevent unnecessary exposure due to equipment malfunction or improper use. Environmental safety is another critical component, necessitating the safe disposal of radioactive materials and the adoption of energy-efficient technologies to reduce the environmental footprint of medical imaging. Regulatory compliance with international safety standards, such as those set by the International Commission on Radiological Protection (ICRP) and national bodies, is essential for ensuring consistent safety practices across healthcare institutions. Future directions in radiation safety include the integration of digital health technologies to monitor and manage radiation exposure more effectively, and ongoing research into novel imaging techniques that could further reduce radiation risks. Collaboration between healthcare providers, researchers, and policymakers is crucial to advancing safety standards and improving risk management strategies in medical imaging. This review highlights the importance of a comprehensive approach to managing radiation risks in medical imaging, emphasizing the need for continuous innovation, education, and policy support to protect patients, healthcare workers, and the environment.

Pulmonary nodule visualization and evaluation of AI-based detection at various ultra-low-dose levels using photon-counting detector CT.

Radiation dose should be as low as reasonably achievable. With the invention of photon-counting detector computed tomography (PCD-CT), the radiation dose may be considerably reduced. To evaluate the potential of PCD-CT for dose reduction in pulmonary nodule visualization for human readers as well as for computer-aided detection (CAD) studies. A chest phantom containing pulmonary nodules of different sizes/densities (range 3-12 mm and -800-100 HU) was scanned on a PCD-CT with standard low-dose protocol as well as with half, quarter, and 1/40 dose (CTDIvol 0.4-0.03 mGy). Dose-matched scans were performed on a third-generation energy-integrating detector CT (EID-CT). Evaluation of nodule visualization and detectability was performed by two blinded radiologists. Subjective image quality was rated on a 5-point Likert scale. Artificial intelligence (AI)-based nodule detection was performed using commercially available software. Highest image noise was found at the lowest dose setting of 1/40 radiation dose (eff. dose = 0.01mSv) with 166.1 ± 18.5 HU for PCD-CT and 351.8 ± 53.0 HU for EID-CT. Overall sensitivity was 100% versus 93% at standard low-dose protocol (eff. dose = 0.2 mSv) for PCD-CT and EID-CT, respectively. At the half radiation dose, sensitivity remained 100% for human reader and CAD studies in PCD-CT. At the quarter radiation dose, PCD-CT achieved the same results as EID-CT at the standard radiation dose setting (93%, P = 1.00) in human reading studies. The AI-CAD system delivered a sensitivity of 93% at the lowest radiation dose level in PCD-CT. At half dose, PCD CT showed pulmonary nodules similar to full-dose PCD, and at quarter dose, PCD CT performed comparably to standard low-dose EID CT. The CAD algorithm is effective even at ultra-low doses.

Characterization of kilovoltage x-ray image guidance system with a novel post-processing algorithm on a new slip ring-mounted radiotherapy system.

This study evaluates the performance of a kilovoltage x-ray image-guidance system equipped with a novel post-processing optimization algorithm on the newly introduced TAICHI linear accelerator (Linac). A comparative study involving image quality tests and radiation dose measurements was conducted across six scanning protocols of the kV-cone beam computed tomography (CBCT) system on the TAICHI Linac. The performance assessment utilized the conventional Feldkamp-Davis-Kress (FDK) algorithm and a novel Non-Local Means denoising and adaptive scattering correction (NLM-ASC) algorithm. Image quality metrics, including spatial resolution, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR), were evaluated using a Catphan 604 phantom. Radiation doses for low-dose and standard protocols were measured using a computed tomography dose index (CTDI) phantom, with comparative measurements from the Halcyon Linac's iterative CBCT (iCBCT). The NLM-ASC algorithm significantly improved image quality, achieving a 300%-1000% increase in CNR and SNR over the FDK-only images and it also showed a 100%-200% improvement over the iCBCT images from Halcyon's head protocol. The optimized low-dose protocols yielded higher image quality than the standard FDK protocols, indicating potential for reduced radiation exposure. Clinical implementation confirmed the TAICHI system's utility for precise and adaptive radiotherapy. The kV-IGRT system on the TAICHI Linac, with its novel post-processing algorithm, demonstrated superior image quality suitable for routine clinical use, effectively reducing image noise without compromising other quality metrics.

Accuracy of Ultralow-Dose Photon-counting CT in the Detection of Lung Changes after Lung Transplant.

Background Data on the diagnostic accuracy of ultralow-dose (ULD) CT protocols for periodic surveillance in recipients of lung transplant are lacking. Purpose To assess the potential for radiation dose reduction using ULD photon-counting CT (PCT) to detect lung abnormalities in recipients of lung transplant during repeat CT follow-up. Materials and Methods Consecutive adult recipients of lung transplant undergoing same-day standard-of-care low-dose (LD) and ULD PCT from March 2023 to May 2023 were prospectively included. The ULD protocols were performed with two target effective doses comprising 20% (hereafter, ULD1) and 10% (hereafter, ULD2) of the standard LD protocol. The 1-mm reconstructions were reviewed by three readers. Subjective image quality, the visibility of certain anatomic structures (using a five-point Likert scale), and the presence of lung abnormalities were independently assessed. The χ2 or t tests were used to evaluate differences between the ULD1 and ULD2 protocols. Results A total of 82 participants (median age, 64 years [IQR, 54-69 years]; 47 male) were included (41 participants for each ULD protocol). The mean effective doses per protocol were 1.41 mSv ± 0.44 (SD) for LD, 0.26 mSv ± 0.08 for ULD1, and 0.17 mSv ± 0.04 for ULD2. According to three readers, the subjective image quality of the ULD images was deemed diagnostic (Likert score ≥3) in 39-40 (ULD1) and 40-41 (ULD2) participants, and anatomic structures could be adequately visualized (Likert score ≥3) in 33-41 (ULD1) and 34-41 (ULD2) participants. The detection accuracy for individual lung anomalies exceeded 70% for both ULD protocols, except for readers 1 and 3 detecting proximal bronchiectasis and reader 3 detecting bronchial wall thickening and air trapping. No evidence of a statistically significant difference in noise (P = .96), signal-to-noise ratio (P = .77), or reader accuracy (all P ≥ .05) was noted between the ULD protocols. Conclusion ULD PCT was feasible for detecting lung abnormalities following lung transplant, with a tenfold radiation dose reduction. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ciet in this issue.

Low-Dose Triple-Pill vs Standard-Care Protocols for Hypertension Treatment in Nigeria

With the high burden of hypertension in sub-Saharan Africa, there is a need for effective, safe and scalable treatment strategies. To compare, among Black African adults, the effectiveness and safety of a novel low-dose triple-pill protocol compared with a standard-care protocol for blood pressure lowering. Randomized, parallel-group, open-label, multicenter trial conducted in public hospital-based family medicine clinics in Nigeria. Black African adults with uncontrolled hypertension (≥140/90 mm Hg) who were untreated or receiving a single blood pressure-lowering drug. Participants were randomly allocated to low-dose triple-pill or standard-care protocols. The triple-pill protocol involved a novel combination of telmisartan, amlodipine, and indapamide in triple one-quarter, one-half, and standard doses (ie, 10/1.25/0.625 mg, 20/2.5/1.25 mg, and 40/5/2.5 mg), with accelerated up-titration. The standard-care protocol was the Nigeria hypertension treatment protocol starting with amlodipine (5 mg). The primary effectiveness outcome was the reduction in home mean systolic blood pressure, and the primary safety outcome was discontinuation of trial treatment due to adverse events, both from randomization to month 6. The first participant was randomized on July 19, 2022, and the last follow-up visit was on July 18, 2024. Among 300 randomized participants (54% female; mean age, 52 years; baseline mean home blood pressure, 151/97 mm Hg; and clinic blood pressure, 156/97 mm Hg), 273 (91%) completed the trial. At month 6, mean home systolic blood pressure was on average 31 mm Hg (95% CI, 28 to 33 mm Hg) lower in the triple-pill protocol group and 26 mm Hg (95% CI, 22 to 28 mm Hg) lower in the standard-care protocol group (adjusted difference, -5.8 mm Hg [95% CI, -8.0 to -3.6]; P < .001]). At month 6, clinic blood pressure control (<140/90 mm Hg) was 82% vs 72% (risk difference, 10% [95% CI, -2% to 20%]) and home blood pressure control (<130/80 mm Hg) was 62% vs 28% (risk difference, 33% [95% CI, 22% to 44%]) in the triple-pill compared with the standard-care protocol group; these were 2 of 21 prespecified secondary effectiveness end points. No participants discontinued trial treatment due to adverse events. Among Black African adults with uncontrolled hypertension, a low-dose triple-pill protocol achieved better blood pressure lowering and control with good tolerability compared with the standard-care protocol. Pan African Clinical Trials Registry Identifier: PACTR202107579572114.

Is a Low-Dose Triple-Drug Combination Pill Protocol the Answer for Hypertension Control in Sub-Saharan Africa?

Is a Low-Dose Triple-Drug Combination Pill Protocol the Answer for Hypertension Control in Sub-Saharan Africa?

Inpatient initiation of long-acting injectable buprenorphine at a community hospital: A retrospective case series

Objectives Determine if long-acting injectable buprenorphine (LAIB) can be successfully and safely administered in the hospital with minimal sublingual buprenorphine lead-in and potentially improve follow-up engagement in care. Methods We performed a retrospective case series of 46 patients who received LAIB while hospitalized at a safety-net community hospital. We abstracted demographic information, details about substance use disorder treatment history, in-hospital buprenorphine initiation methods and follow-up data from inpatient and outpatient electronic medical records. Results In total, 46 hospitalized patients received LAIB during the study period. The majority of our patients were older Black adults with Medicaid who self-reported intranasal heroin use. A low-dose buprenorphine initiation protocol was used most commonly, either in sublingual or intravenous form, with only two cases of precipitated withdrawal occurring during the buprenorphine initiation process and no cases of precipitated withdrawal after the administration of LAIB. 87% (40) of the patients received LAIB after receiving either sublingual or IV buprenorphine for fewer than the recommended seven days. Of the 46 hospitalized patients who received LAIB, 23 (50%) attended a follow-up addiction medicine appointment within 30 days of discharge. Conclusions Hospital administration of LAIB could play an important role in retention in care after hospital discharge.

Reducing Radiation Exposure in the Cath Lab Using a New Low-Dose Protocol

Reducing Radiation Exposure in the Cath Lab Using a New Low-Dose Protocol

Geometric accuracy of low-dose CT scans for use in shoulder musculoskeletal research applications

Computed tomography (CT) imaging is frequently employed in a variety of musculoskeletal research applications. Although research studies often use imaging protocols developed for clinical applications, lower dose protocols are likely possible when the goal is to reconstruct 3D bone models. Our purpose was to describe the dose-accuracy trade-off between incrementally lower-dose CT scans and the geometric reconstruction accuracy of the humerus, scapula, and clavicle. Six shoulder specimens were acquired and scanned using 5 helical CT protocols: 1) 120 kVp, 450 mA (full-dose); 2) 120 kVp, 120 mA; 3) 120 kVp, 100 mA; 4) 100 kVp, 100 mA; 5) 80 kVp, 80 mA. Scans were segmented and reconstructed into 3D surface meshes. Geometric error was assessed by comparing the surfaces of the low-dose meshes to the full-dose (gold standard) mesh and was described using mean absolute error, bias, precision, and worst-case error. All low-dose protocols resulted in a >70 % reduction in the effective dose. Lower dose scans resulted in higher geometric errors; however, error magnitudes were generally <0.5 mm. These data suggest that the effective dose associated with CT imaging can be substantially reduced without a significant loss of geometric reconstruction accuracy.