Reduction In Effective Dose Research Articles

Image quality assessment of the CARE kV for pediatric CT angiography: A feasibility study of over 50% effective dose reduction

Image quality assessment of the CARE kV for pediatric CT angiography: A feasibility study of over 50% effective dose reduction

Survival after osimertinib dose-reduction, discontinuation in 1L EGFR -mutated metastatic non-small cell lung cancer (mNSCLC).

8587 Background: Osimertinib (osi) has become standard of care in 1L EGFR mt (+) mNSCLC following the FLAURA trial in patients (pts) with classical sensitizing mutations. However, limited data are available on the effect of osimertinib dose reductions on survival outcomes compared to pts on full dose. Methods: We performed a single-institution retrospective analysis of pts with EGFR -mutated mNSCLC treated with 1L osi from 2018-2023 Clinical trial pts were excluded. Pts who underwent dose reduction were compared to those maintained on full dose (at least 80mg daily). Baseline demographics, disease characteristics, treatment history, toxicity, and clinical outcomes were abstracted from the electronic medical record (EMR) and compared using independent sample t-tests and chi-square analyses as appropriate. Median progression free survival (mPFS) and overall survival (mOS) were compared via Kaplan-Meier log-rank analysis and Cox regression analysis, with sex, race, age, PS, smoking hx, CNS involvement, and mutation status included a priori . Results: 171 pts with mNSCLC treated with 1L osi were identified. 26 (15%) required dose reduction. Patient sex (p=0.458), racial distribution (p=0.421), ECOG PS>1 at diagnosis (p=0.730) and smoking history (p=0.485) were comparable between reduced dose and full dose pts (Table 1). 44% vs 34% had CNS metastases at diagnosis (p=0.192). Rates of TP53 (p=0.712) and atypical EGFR mutations (p=0.393) were also comparable. All dose-reduced pts experienced AEs, compared to 48% of full-dose pts (p<0.001). Dose-reduced pts had inferior mPFS (17.0 months [11.5-22.5]) compared to full-dose pts (24.6[19.2-28.8]; p=0.043. PFS with dose-reduction was inferior compared to full dose with (p=0.041) or without CNS metastases (p=0.048). On multivariable analysis, dose-reduction was associated with inferior PFS (p=0.047) regardless of baseline characteristics. OS, however, was comparable in pts with and without dose-reduction (36.7 [28.1-45.4] vs 39.2 [34.8-43.7]; p=0.749)). 14 pts (8%) discontinued osi due to AEs, of whom 9 (64%) were previously dose reduced. mPFS was comparable (p=0.334) between pts who discontinued and those who did not, as was mOS (p=0.910). Conclusions: Dose reduction of osimertinib was relatively uncommon and associated with inferior PFS but similar OS in 1L pts with EGFR -mutated mNSCLC. Baseline characteristics and survival. Baseline Characteristics Dose reduced (n=26) Full dose (n=145) Sig (p) Female 59.6% 63.0% 0.458 Race 0.421 White 63.0% 67.0% Black 3.7% 12.3% Asian 33.3% 19.1% ECOG PS>1 0% 6.8% 0.730 Smoking Hx 37.0% 39.7% 0.485 CNS mets 44.4% 33.5% 0.192 Mutation Status TP53 55.7% 53.1% 0.712 L858R 35.8% 38.2% 0.675 Exon19del 45.7% 45.0% 0.819 Atypical mutation 18.5% 16.8% 0.393 Adverse Events (AEs) Experienced AEs 100% 48.3% <0.001 Discontinued due to AE 34.6% 3.4% <0.001 Survival (months) mPFS 17.0[11.5-22.5] 24.6[19.2-28.8] 0.043 mOS 36.7 [28.1-45.4] 39.2 [34.8-43.7] 0.910 Significant findings in bold.

Personalized dose reduction strategies for biologic disease-modifying antirheumatic drugs for treating axial spondyloarthritis: a clinical and economic evaluation with predictive modeling

BackgroundAxial spondyloarthritis (AS) is a chronic inflammatory disease that significantly affects quality of life and imposes a high economic burden on patients due to the cost of biologic disease-modifying antirheumatic drugs (bDMARDs). Dose reduction strategies for bDMARDs may offer a feasible approach to maintaining clinical efficacy while reducing costs. This study aimed to evaluate the clinical effectiveness and cost-efficiency of bDMARD dose reduction in patients with AS and apply machine learning to identify key factors influencing disease control.MethodsThis 12-month prospective study, 368 AS patients receiving ≥ 3 months of full-dose bDMARDs were included. Among 215 initial responders (ASDAS < 2.1), 146 underwent dose reduction while 69 continued full-dose therapy. Clinical outcomes such as C-reactive protein (CRP) levels, the Bath ankylosing spondylitis disease activity index (BASDAI) and ankylosing spondylitis disease activity score (ASDAS) were assessed, along with cost effectiveness using incremental cost effectiveness ratios (ICER). Random forest models were developed to predict the achievement of inactive disease (ASDAS < 1.3) and to identify key predictors.ResultsThe dose reduction group demonstrated significantly greater improvements in CRP (-4.05 vs. +2.83 mg/L, p < 0.001), BASDAI (-3.00 vs. +0.89, p < 0.001), and ASDAS (-1.42 vs. +0.09, p < 0.001) compared to the full dose group. A greater proportion of patients in the reduced dose group achieved ASDAS < 1.3 at 12 months (93.2% vs. 33.3%, p < 0.001), with a shorter median time to response (4.20 vs. 4.70 months, p < 0.001). The ICER for achieving ASDAS < 1.3 was favorable (–$6,209.78; 95% CI:–$9,048.35 to–$4,015.78), supporting the cost-effectiveness of dose reduction. A random forest model identified reduced dose strategy, baseline ASDAS, BASDAI, treatment duration, and CRP as key predictors of ASDAS < 1.3, achieving an AUC of 0.845 and F1-score of 0.774.ConclusionsIn this cohort, bDMARD dose reduction was associated with preserved clinical outcomes and lower costs, suggesting it may be a viable strategy for selected patients under close clinical supervision. Predictive modeling provided actionable insights to optimize personalized treatment strategies, balancing efficacy and economic sustainability. These findings support further evaluation of dose reduction strategies, especially in resource-limited settings, to inform potential integration into routine practice.

Steroid-sparing effect of levilimab in rheumatoid arthritis in real practice

Aim. Evaluation in real clinical practice steroid-sparing effect of levilimab therapy in patients with highly and moderately active rheumatoid arthritis (RA). Materials and methods. Retrospective observational study (1 year) held at the Republican Clinical Diagnostic Center for the period from November 2022 to July 2023. All patients received corticosteroids (CS) at the time of levilimab (LVL) administration. The assessment of the decrease in the dosage of CS was carried out at 12, 24 and 52 weeks from the start of LVL-therapy. Results. The analysis included 73 patients with RA (60 women and 13 men, average age – 56.3±10.5 years), the average dose of CS at the time of LVL initiation was 5.7±2 mg/day with an average duration of CS intake of 87.5 months [7; 137]. Twenty patients included in the follow-up received CS at a dosage of ≥5 mg. Of the 73 patients, by the end of the study, it was possible to achieve a reduction in the dosage of CS in 22 (30.1%) patients, and complete elimination of CS in 36 patients (49.3%). Only 3 patients received CS at a dosage of ≥5 mg after 52 weeks. Against the background of taking LVL, patients showed a decrease in clinical and laboratory activity of RA according to the Disease Activity Score in 28 joints with C-reactive protein indices by 47.1% and Disease Activity Score in 28 joints with Erythrocyte Sedimentation Rate by 48.2%. The positive dynamics of laboratory parameters was noted – a decrease in the level of C-reactive protein by 90.5% and ESR by 72%. During the observation a favorable safety profile of LVL was noted. The most frequently reported adverse event was an increase in alanine aminotransferase and aspartate aminotransferase, recorded in 41 patients (56.1%). One adverse event met the criteria of severity 3 according to Common Terminology Criteria for Adverse Events version 5.0 – lung carcinoma with unspecified cell type, stage 1. Conclusion. Levilimab is a highly effective therapy option for patients with RA with a favorable tolerability and safety profile, against which an effective dose reduction and complete elimination of steroids is possible.

Optimization study on neutron/γ radiation-protective clothing materials with computational human phantoms.

The applications of nuclear science and technology in both production and daily life are becoming increasingly widespread. Radiation shielding, as a critical component, ensures environmental safety and protects human health. In this study, 20 shielding schemes were designed using ethylene-propylene diene monomer as the base material. These schemes incorporated various proportions of boron carbide and gadolinium oxide as neutron-absorbing components and tungsten as the gamma-shielding component. Based on the Chinese reference adult male (CRAM) voxel model and using an anterior-posterior (AP) irradiation setup, the Monte Carlo method was employed to calculate 28 organ/tissue doses and effective dose reductions from neutron and gamma radiation across the 20 material compositions. Each case was evaluated at three different thicknesses-1, 3, and 5mm-with Monte Carlo calculation errors controlled within 1%. Results indicated that, for any composite shielding material, the 5-mm thickness provided optimal protection. When an unmoderated and unthermalized 252Cf neutron source was used, effective dose reductions ranged from 32.60% to 38.75% compared to the unshielded case. With a monoenergetic neutron source at 1keV, the reduction range was between 57.62% and 69.42%. The trend in changes for different composite shielding materials under neutron sources at different energy levels is consistent. When 137Cs served as the gamma source, effective dose reductions ranged from 7.96% to 20.97%, demonstrating that the composite materials offer substantial protection for both neutron and gamma radiation. Additionally, it was found that organs partially exposed outside the shielding material experienced a slight increase in dose due to neutron scattering. In practical applications, full-body protection should be implemented to mitigate this issue.

The effect of dose reduction of CDK4/6 inhibitors on survival in postmenopausal HR+ HER2-negative metastatic breast cancer

ABSTRACT Background This study aimed to evaluate the effect of dose reduction of CDK4/6 inhibitors on survival outcomes in postmenopausal patients with HR+HER2-negative metastatic breast cancer (mBC). Methods A retrospective cohort study was conducted involving 164 postmenopausal patients with HR+ HER2-negative mBC who received CDK4/6 inhibitors between 2021 and 2024. Clinical parameters were systematically analyzed. Progression-free survival (PFS) and overall survival (OS) were evaluated based on dose reduction status. Survival outcomes were estimated using the Kaplan-Meier method, and independent prognostic factors were identified through multivariate Cox regression analysis. Results The median age was 61 years, with a median follow-up of 23.5 months. The median PFS was 23.3 months, while median OS was not reached. Dose reduction occurred in 45 patients (27%), who exhibited significantly worse survival (PFS HR: 1.67, 95% CI: 1.02–2.72, p = 0.042; OS HR: 2.54, 95% CI:1.34–4.83, p = 0.004). Dose reduction and liver metastases were independent risk factors for shorter PFS and OS, while treatment in later lines was associated with shorter PFS. Conclusion Dose reductions in CDK4/6 inhibitors were associated with worse survival outcomes in postmenopausal HR+ HER2− mBC patients. Future biomarker-driven studies are needed to guide personalized dose adjustments and optimize treatment efficacy.

Comparison of ICS dose reduction vs. montelukast discontinuation for step-down therapy in well-controlled asthma: a pilot randomized controlled trial

BackgroundWhile asthma guidelines advocate for reducing inhaled corticosteroid (ICS) doses in well-controlled patients, limited evidence exists to directly support this approach. This study aimed to compare the effectiveness of ICS dose reduction versus montelukast discontinuation as step-down strategies in adults with well-controlled asthma.MethodsThis single-center, pilot randomized controlled trial enrolled 73 adults with well-controlled asthma. Participants were randomized to either Group A: ICS Dose Reduction (n = 37) or Group B: Montelukast Discontinuation (n = 36). Both groups received standard care and their designated intervention for three months. The primary outcome was asthma control measured by the ACT score. Secondary outcomes included lung function, asthma exacerbation frequency, treatment failure rates, and cough symptoms. Medication adherence was assessed using dose counters and pill counts.ResultsThere was no significant difference in overall asthma control between the groups, as measured by the ACT score (p = 0.42). However, patients in Group A (reduced ICS) experienced significantly fewer treatment failures compared to Group B (discontinued montelukast) at three months (p = 0.01). No serious adverse events were reported.ConclusionAlthough the ACT scores did not significantly differ between the groups, we did observe a trend towards fewer treatment failures in the ICS reduction group. This suggests that reducing ICS doses may help to maintain asthma control and reduce the risk of exacerbations. However, further research is warranted to confirm these findings in larger, long-term studies.Trial registrationIRCT Registration Number IRCT2016052428037N1, Retrospectively registered, Registration Date 20,160,701.Graphical abstract

The Effect of Simulated Dose Reduction on the Performance of Artificial Intelligence in Chest Radiography.

Chest imaging plays a pivotal role in screening and monitoring patients, and various predictive artificial intelligence (AI) models have been developed in support of this. However, little is known about the effect of decreasing the radiation dose and, thus, image quality on AI performance. This study aims to design a low-dose simulation and evaluate the effect of this simulation on the performance of CNNs in plain chest radiography. Seven pathology labels and corresponding images from Medical Information Mart for Intensive Care datasets were used to train AI models at two spatial resolutions. These 14 models were tested using the original images, 50% and 75% low-dose simulations. We compared the area under the receiver operator characteristic (AUROC) of the original images and both simulations using DeLong testing. The average absolute change in AUROC related to simulated dose reduction for both resolutions was <0.005, and none exceeded a change of 0.014. Of the 28 test sets, 6 were significantly different. An assessment of predictions, performed through the splitting of the data by gender and patient positioning, showed a similar trend. The effect of simulated dose reductions on CNN performance, although significant in 6 of 28 cases, has minimal clinical impact. The effect of patient positioning exceeds that of dose reduction.

Reduction of effective dose in vascular interventions to enhance radiation safety

Reduction of effective dose in vascular interventions to enhance radiation safety

Patient Shielding in Ultra-High-Resolution Cone-Beam CT of the Upper Extremity with a Twin Robotic X-Ray System.

Background/Objectives: Gantry-free cone-beam CT (CBCT) allows for ultra-high-resolution (UHR) upper extremity imaging in a comfortable tableside position. The aim of this study was to assess the organ-specific radiation burden and the effect of dedicated lead shielding in the UHR-CBCT of the wrist and elbow. Methods: A modified Alderson-Rando phantom was scanned with the tableside UHR-CBCT mode of a twin robotic X-ray system employing identical scan parameters for wrist and elbow imaging. An ion chamber was used in conjunction with an electrometer to obtain representative organ dose measurements for the eye lens, thyroid gland, breast tissue, and abdomen. All measurements were performed with and without lead shielding. Results: Irrespective of the examined upper extremity joint, the highest absorbed dose among the assessed organs was determined for the eye lens (wrist imaging: 0.10 ± 0.01 mGy, elbow imaging: 0.12 ± 0.01 mGy). The most effective organ dose reduction by means of shielding in wrist CBCT was achieved for the thyroid gland (-17%). In elbow CBCT, the abdomen (-48%) and the ipsilateral breast (-39%) benefited particularly from shield protection. Conclusions: Although shielding was more effective in elbow than wrist scans, the overall impact in terms of absolute dose reduction was marginal.

Implementing tin-prefiltration in routine clinical CT scans of the lower extremity: impact on radiation dose.

Several studies have demonstrated the potential of tin-prefiltration to reduce radiation dose while maintaining diagnostic image quality for musculoskeletal imaging. Still, no study has reported data on the impact of tin-prefiltration on radiation dose reduction for clinical routine scanning. Retrospective inclusion of 300 clinically indicated CT scans of the pelvis, knee, and ankle before January 2020 (without tin filter) and after December 2020 (with tin filter). For each joint, 50 examinations with tin-prefiltration and 50 examinations without tin-prefiltration were selected. Dose parameters were extracted, calculated, and compared. Subjective and quantitative parameters for image quality were assessed. The CTDIvol, DLP, and effective dose were reduced significantly in all tin-prefiltered examinations compared to the non-tin-prefiltered examinations (p < 0.001): CTDIvol was 65% lower in the pelvis, 73% lower in the knee, and 54% lower in the ankle. This reduced the effective dose of 61%, 71%, and 60%, respectively. In absolute numbers, the reduction of the median effective dose delivered in a single CT scan of the pelvis was - 2.29mSv, - 0.15mSv for the knee, and - 0.03mSv for the ankle. No difference in diagnostic image quality, depiction of bone anatomy and soft tissues, and image artifacts was observed (p > 0.05). Subjective and objective image noise was higher in tin-prefiltered pelvis CT (p < 0.001). The implementation of tin-prefiltration in clinical routine scan protocols significantly reduced the effective radiation dose for unenhanced CT scans of the lower extremities between 60 and 70%.

Evaluation of the dose reduction effect of crystalline lens exposure in cone-beam computed tomography with bismuth eye shield for image-guided radiation therapy: An anthropomorphic phantom study.

This study aimed to evaluate the dose-exposure reduction effect of a crystalline lens with a bismuth eye shield using cone-beam computed tomography (CBCT) for head image-guided radiation therapy. The ocular surface dose of the head phantom (THRA-1) is defined as a crystalline lens exposure dose and is measured using a radiophotoluminescence dosimeter (RPLD, GD-352M) with and without an eye shield (CT eye shield) while moving the head phantom from the reference position that is set at the center of the head in either the X or Z direction from -5 to +5cm. The exposure doses were measured thrice at each movement position. The crystalline lens exposure doses at the reference position were 0.896±0.024 mGy and 0.892±0.016 mGy for the right and left sides, respectively. The exposure doses at the position where the head phantom was moved 5cm in the -Z direction from the reference position were 2.812±0.053 mGy and 2.576±0.038 mGy for the right and left sides, respectively, with the highest doses at all movement positions. The crystalline lens exposure doses were reduced to 1.909±0.046 mGy and 1.768±0.043 mGy for the right and left sides with an eye shield in this position, causing an exposure dose reduction rate of -32% and -31%, respectively. The crystalline lens exposure dose reduction rate was approximately 10%-15% in the movement directions, except for the -Z direction. Head CBCT with an eye shield effectively reduced the crystalline lens exposure dose when the CBCT isocenter was set close to the eye. Head CBCT using an eye shield is a useful method that reduces the crystalline lens exposure dose.

Effective Dose Reduction of Emamectin Benzoate Through Inhibition of Bx-SDR3 in Pine Wood Nematode Management.

Pine wood nematodes (Bursaphelenchus xylophilus, PWNs) are a major threat to Pinus koraiensis in northeast China, and emamectin benzoate (EB) is commonly used for their control. Although high doses of EB can alleviate symptoms of pine wilt disease (PWD), they do not fully eradicate PWNs due to their detoxification mechanisms. This study investigates the content of EB in P. koraiensis and its efficacy in controlling PWNs after exogenous application of EB. We found that while EB significantly reduced PWN populations, it did not eliminate them. Transcriptomic analysis of PWNs treated with concentration at 20% (LC20) revealed that PWNs exhibit detoxification responses to low EB concentrations (LC20), driven by the Bx-SDR3 gene. RNA interference (RNAi)-mediated silencing of this gene decreased the detoxification ability of PWNs and enhanced the toxic effects of LC20 EB by 20.9%. These results highlight the key role of Bx-SDR3 in PWN detoxification and suggest that targeting this gene could improve the effectiveness of EB, offering a promising strategy for more efficient and eco-friendly pest management.

Potential for reduction of radiation dose in the assessment of the lead orientation in directional deep brain stimulation electrodes.

Potential for reduction of radiation dose in the assessment of the lead orientation in directional deep brain stimulation electrodes.

Effects of Dose Reduction or Discontinuation of Benzodiazepine Hypnotics on Sleep and Anxiety in Patients With Insomnia After Long-Term Use.

Long-term prescribing of benzodiazepine receptor agonists (BZRAs) is a problem worldwide, but there are no detailed reports on the effects or side effects of reducing or discontinuing the dose. We retrospectively investigated the efficacy and safety of discontinuing or reducing the dose of BZRAs hypnotics after long-term use. Between April 2018 and May 2019, patients with insomnia after long-term use of BZRA hypnotics had BZRA hypnotics discontinued or their dose reduced, and their sleep conditions and anxiety symptoms were assessed. Insomnia severity (primary endpoint) was assessed as the change from baseline after discontinuation or reduction of BZRA hypnotics using the Insomnia Severity Index Japanese version (ISI-J). Changes from baseline in sleep quality and anxiety symptoms (secondary endpoint) from baseline were assessed using the Pittsburgh Sleep Quality Index Japanese version (PSQI-J) and Generalized Anxiety Disorder-7 (GAD-7), respectively. The adverse events were recorded during the study period. Statistical analysis was performed using the Wilcoxon matched-pairs signed rank test for changes in BZRA and concomitant medication dose, PSQI-J and GAD-7, and the paired t-test for changes in ISI-J. The changes in ISI-J (discontinuation group: p = 0.07, reduction group: p = 0.91), PSQI-J (discontinuation group: p = 0.19, reduction group: p = 0.19), and GAD-7 scores (discontinuation group, p = 0.27; reduction group, p = 0.81) were not significant after the BZRA hypnotics were discontinued or reduced. Concomitant medications (antipsychotics and antidepressants) did not change from the baseline. The incidence of each adverse event did not change during the study period. BZRA hypnotics can be discontinued or their dose reduced after long-term use without worsening sleep conditions and anxiety symptoms. Our results may provide a basis for the safe and effective discontinuation or dose reduction of long-term benzodiazepine hypnotics use.

Bovine Serum Albumin Nanoparticle-Mediated Delivery of Ribavirin and Mycophenolic Acid for Enhanced Antiviral Therapeutics.

The global spread of viral diseases is a public health issue. Ribavirin (RBV) and mycophenolic acid (MPA) are well-known wide-spectrum antiviral agents. The present study evaluated the potential of bovine serum albumin (BSA) nanoparticles (NPs) as a vehicle to improve the efficacy of molecules with antiviral activity. The results demonstrated that NPs offer a promising strategy for the delivery of antiviral drugs, improving their stability and reducing toxicity compared to free agents. BSA-based NPs effectively encapsulated hydrophilic molecules such as MPA and water-soluble compounds such as RBV, achieving encapsulation efficiencies of 10% and 20%, respectively. The purified NPs exhibited a particle size between 60 and 100 nm and did not show toxicity at the evaluated concentrations. In cellular viral infection models against Zika virus (ZIKV), Junín virus (JUNV), vesicular stomatitis virus (VSV) and herpes simplex virus (HSV-1), the BSA-based NPs loaded with MPA or RBV demonstrated antiviral properties superior to those of non-encapsulated agents, as well as 100- and 200-fold effective dose reductions, respectively. These findings clearly indicate the potential of BSA NPs as a novel platform for the development of safer and more efficient antiviral therapies.

First Measurement: Proactive Immune Cell Sparing in Radiation Therapy.

Radiation Therapy (RT) can modulate the immune system and generate anti-tumor T cells. However, this anti-tumor-activity is countered by radiation-induced immunosuppression (RIIS). Clinical advantages of proactively sparing RT dose to immune rich organs have not previously been evaluated. We conducted a phase II randomized trial from 2020 to 2023, enrolling 51 early-stage lung cancer patients treated with SBRT, to evaluate the effect of dose reduction to immune rich organs on RIIS. Two groups were: RIIS-optimized-treatment (lowering the dose to blood, bone-marrow and lymph-node-stations) and standard-treatment. All treatments followed national protocol guidelines. Peripheral blood was collected at baseline, immediately, 4-weeks and 6-months post-treatment. ALC changes from baseline immediately, 4-weeks and 6-months post-SBRT are: optimized-arm: -16%, -22%, -16%, standard-arm: -31%, -34%, -26%, leading to an overall-all-time-point improvement in ALC reduction in the optimized-arm compared to the standard-arm of 13.4 (5.3) % (95% CI, 2.8 to 24.0; p = 0.01). Central tumors had the largest improvement in ALC from baseline: optimized-arm: - 8%, -18%, -14%, standard-arm: -39%, -43%, -47%, leading to an overall-all-time-point improvement in ALC reduction in the optimized-arm compared to the standard-arm of 29.5 (9.6) % (95% CI, 10.1 to 48.9; p = 0.004). Grade 3 lymphopenia occurred in 15.4% of standard arm patients but was absent in the optimized arm. Additionally, 2.8 times more patients in the optimized arm experienced an ALC increase post-SBRT. Dose to organs such as the heart, great vessels, thoracic spine, and lymph nodes significantly correlated with RIIS. A trend towards increased Event-Free-Survival (two-year: 75.0% (SE = 10.8%) versus 59.8% (SE = 11.2%), p =0·10) and Overall Survival (two-year: 93.4% (SE=6.1%) versus 69.4% (SE=10.5%), p =0·14) was observed with optimized-planning compared to standard-planning in treatment naïve patients. Reducing RT dose to immune rich organs significantly reduces RIIS compared to standard-of-care. This has implications in enhancing immune system mediated anti-tumor-activity. (Funded by National Cancer Institute and others. ClinicalTrials.gov number, NCT04273893 ).

Evaluation of Exposure Dose Reduction Effect for Cone-beam Computed Tomography with Bismuth Sheet in Image-guided Radiation Therapy of Prostate Cancer

Image-guided radiation therapy using cone-beam computed tomography (CBCT) for prostate cancer is problematic due to the increasing exposure dose at each treatment session. This study aimed to evaluate the effect of exposure dose reduction using bismuth sheets for pelvic CBCT. Using a radiophotoluminescence dosimeter (GD-352M) and CBCT imaging conditions with three X-ray tube rotation angles (292°-88°, 92°-248°, and 92°-88°), absorbed doses were measured in the rectum, anterior and posterior bladder walls, right and left pelvic subcutaneous at 5 cm superior the prostate center of the pelvic phantom and in a testis. Next, the same measurements were performed when these measurement points were covered with a bismuth sheet. The absorbed doses at 92°-248° with the bismuth sheets were reduced by 31.3% from 16.3±0.2 mGy to 11.2±0.2 mGy for the rectum and by 57.1% from 45.0±2.7 mGy to 19.3±1.0 mGy for the testis, which were the lowest among the imaging conditions. Although the anterior and posterior bladder walls were the highest dose at 48.7±11.5 and 20.2±0.4 mGy, the high reduction rates of 42.0% and 36.9%, respectively. From the viewpoint of the exposure risk to the bladder, rectum, and testis, using bismuth sheets and the X-ray tube rotation angle of 92°-248° effectively reduced the exposure dose.

Dose Reduction Effects of Face Masks against Radon Progeny Inhalation (1):

Dose Reduction Effects of Face Masks against Radon Progeny Inhalation (1):

Evaluation of Dose Reduction Effects and Image Quality Based on Storage Methods in Coronary Angiography

Evaluation of Dose Reduction Effects and Image Quality Based on Storage Methods in Coronary Angiography