Effect of combination treatment of protocatechuic acid with 5-fluorouracil and oxaliplatin on colon cancer Caco-2 cell line

Among the most common antitumor drugs used in the treatment of colon cancer are 5-fluorouracil and oxaliplatin (5-FU and OXA). However, both these drugs have many side effects, and hence there is a need for new treatment\approach to reduce the side effects aas well as drug concentration. In this context, here, we investigated the effect of addition of protocatechuic acid (PCA) onto either monotherapies or combination therapies of 5-FU and OXA on the human colon cancer (Caco-2) cell line. In addition, we did evaluate the synergistic effect of PCA with 5-FU and OXA. Further, we determined the suppressive effects of different doses of PCA alone or in combination with 5-FU/OXA on cell proliferation after 24 and 48 hours. We identified a suppressive effect of PCA on cell viability at 48 h starting from the dose of 50 µM Matrix metalloproteinase-2 (MMP-2) and MMP-9 gene expression levels and apoptotic effects showed significant increases and decreases depending on the dose and time applied in the experimental groups. The highest synergistic activity was seen at 2:1 concentration of 5-FU+ PCA. Our findings indicate the presence of the cytotoxic and apoptotic effects of PCA in Caco-2 cells at 48 h, increasing with a dose- and time-dependent manner.

Quality of Images Reconstructed by Deep Learning Reconstruction Algorithm for Head and Neck CT Angiography at 100 kVp / 中国医学科学院学报

Objective To evaluate the impact of deep learning reconstruction algorithm on the image quality of head and neck CT angiography (CTA) at 100 kVp. Methods CT scanning was performed at 100 kVp for the 37 patients who underwent head and neck CTA in PUMC Hospital from March to April in 2021.Four sets of images were reconstructed by three-dimensional adaptive iterative dose reduction (AIDR 3D) and advanced intelligent Clear-IQ engine (AiCE) (low,medium,and high intensity algorithms),respectively.The average CT value,standard deviation (SD),signal-to-noise ratio (SNR),and contrast-to-noise ratio (CNR) of the region of interest in the transverse section image were calculated.Furthermore,the four sets of sagittal maximum intensity projection images of the anterior cerebral artery were scored (1 point:poor,5 points:excellent). Results The SNR and CNR showed differences in the images reconstructed by AiCE (low,medium,and high intensity) and AIDR 3D (all P<0.01).The quality scores of the image reconstructed by AiCE (low,medium,and high intensity) and AIDR 3D were 4.78±0.41,4.92±0.27,4.97±0.16,and 3.92±0.27,respectively,which showed statistically significant differences (all P<0.001). Conclusion AiCE outperformed AIDR 3D in reconstructing the images of head and neck CTA at 100 kVp,being capable of improving image quality and applicable in clinical examinations.

Determining the Feasibility of Dose Reduction Strategies on Radiation Dose: An Experimental Phantom Study

@#Introduction: Radiation exposure during the CT examination has always been a concern due to its associated cancer risk. The guidelines suggest the optimization of radiation dose reduction. Therefore, this study aims to determine the feasibility of dose reduction strategies on radiation dose reduction using a phantom. Methods: Head and body phantoms of 16 cm and 32 cm, respectively, were used to calculate the radiation dose and measure the quantitative image quality. The phantoms were positioned and scanned with the standard protocol and low dose protocol. For dose reduction strategies, scan length was reduced in head phantom, and tube voltage and tube current were manipulated individually and by combining both and tested in both head and body phantoms. Also, the influence of rotation time was investigated in body phantom. Quantitative image quality was determined by drawing a region of interest on the obtained image. Results: Reducing scan length showed 41% reduction of radiation dose and reducing tube current, and tube voltage showed up to 75% reduction of radiation dose in head phantom and 70% reduction of radiation dose in body phantom compared to the standard protocol. The reduction of the rotation time, however, reduced the scan time and the radiation dose but the maximum mAs or tube current allowed was limited. Quantitative image quality was reduced when using a lower dose protocol. Conclusion: The dose reduction strategies showed a reduced dose, but the quantitative image quality score was reduced when scanned with low dose protocol. Further manipulation can be performed to maintain image quality.

Colombian Association of Rheumatology. Consensus on recommendations to decrease and discontinue biological therapy in patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis / Asociación Colombiana de Reumatología. Consenso sobre recomendaciones para disminución y descontinuación de la terapia biológica en pacientes con artritis reumatoide, espondilitis anquilosante y artritis psoriásica

A B S T R A C T Objective: The objective of this study was to establish recommendations for the reduction and discontinuation of biological disease-modifying antirheumatic drugs, with the aim of becoming a guide document for health professionals involved in the management of patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis. Materials and methods: The recommendations were established through consensus by a panel of experts in rheumatology, and based on the analysis of available scientific evidence obtained from systematic reviews and the clinical experience of the panellists. Results: A total of 33 rheumatoid arthritis related studies were included, with 6 psoriatic arthritis related, and 9 ankylosing Spondylitis related. The recommendations for the reduction of biological therapies were made by establishing a plan to determine when and how to reduce the biological disease-modifying antirheumatic drugs in patients with these 3 diseases, and in some cases lead to the discontinuation of these treatments. Conclusion: The recommendations established in this document will serve as a guide to improve the efficiency of biological therapy in these diseases, reduce the variability in clinical practice, and establish an adequate risk/benefit ratio.

RESUMEN Objetivo: El objetivo de este estudio fue establecer recomendaciones para la disminución y descontinuación de la terapia biológica con el fin de que se convierta en un documento guía para los profesionales de la salud involucrados en el manejo de pacientes con artritis reumatoide, espondilitis anquilosante y artritis psoriásica. Materiales y métodos: Las recomendaciones fueron establecidas mediante consenso desarrollado a través de un panel de expertos en reumatología, basado en el análisis de la evidencia científica disponible obtenida de revisiones sistemáticas y sobre la experiencia clínica de los panelistas. Resultados: Se incluyeron 33 estudios relacionados con artritis reumatoide, 6 de artritis psoriásica y 9 de espondilitis anquilosante. Las recomendaciones para la disminución de las terapias biológicas se realizaron estableciendo un plan para determinar cuándo y cómo reducir los fármacos biológicos modificadores de enfermedades reumáticas en pacientes con estas 3 enfermedades y en algunos casos conducir a la descontinuación de estos tratamientos. Conclusión: Las recomendaciones establecidas en este documento servirán de guía para mejorar la eficiencia de la terapia biológica en estas enfermedades, reducir la variabilidad en la práctica clínica y establecer de manera adecuada una relación riesgo/beneficio.

Radiation dose reduction in chest dual-energy computed tomography: effect on image quality and diagnostic information / Redução da dose de radiação na tomografia computadorizada de dupla energia do tórax: efeito na qualidade das imagens e na informação diagnóstica

Abstract Objective: To determine whether dual-energy computed tomography (DECT) of the chest can be performed at a reduced radiation dose, with an emphasis on images generated with post-processing techniques. Materials and Methods: In 21 patients undergoing DECT of the chest in a dual-source scanner, an additional image series was acquired at a reduced radiation dose. Four thoracic radiologists assessed both image series for image quality, normal thoracic structures, as well as pulmonary and mediastinal abnormalities, on virtual monochromatic images at 40 keV and 60 keV. Data were analyzed with Student's t-test, kappa statistics, analysis of variance, and the Wilcoxon signed-rank test. Results: The overall image quality of 60 keV virtual monochromatic images at a reduced radiation dose was considered optimal in all patients, and no abnormalities were missed. Contrast enhancement and lesion detection performance were comparable between reduced-dose images at 40 keV and standard-of-care images at 60 keV. The intraobserver and interobserver agreement were both good. The mean volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose-length product (DLP), and effective dose (ED) for reduced-dose DECT were 3.0 ± 0.6 mGy, 4.0 ± 0.6 mGy, 107 ± 30 mGy.cm, and 1.5 ± 0.4 mSv, respectively. Conclusion: DECT of the chest can be performed at a reduced radiation dose (CTDIvol < 3 mGy) without loss of diagnostic information.

Resumo Objetivo: Verificar se a tomografia computadorizada de dupla energia (TCDE) do tórax pode ser realizada com baixas doses de radiação, com ênfase em imagens pós-processadas. Materiais e Métodos: Em 21 pacientes submetidos a DECT do tórax foi adicionada uma série de imagens adquiridas com baixas doses de radiação. Quatro radiologistas com especialidade em tórax avaliaram a qualidade, visualização de estruturas torácicas normais e também anormalidades pulmonares e mediastinais das imagens monocromáticas de baixa energia (40 e 60 keV). Os dados foram analisados utilizando t-test, estatística kappa, análise de variância e teste Wilcoxon. Resultados: A qualidade das imagens monocromáticas de baixa energia (60 keV) com doses reduzidas foi considerada ótima para todos os pacientes e nenhuma anormalidade no tórax foi perdida. O realce pelo contraste e a performance de detecção de lesões foram similares nas imagens com radiação reduzida e com radiação padrão. Boa concordância intra-avaliadores e interavaliadores foi observada. A média dos parâmetros CTDIvol, SSDE, DLP e ED para TCDE de baixa dose foram 3,0 ± 0,6 mGy, 4,0 ± 0,6 mGy, 107 ± 30 mGy.cm e 1,5 ± 0,4 mSv, respectivamente. Conclusão: TCDE do tórax pode ser realizada com baixas doses de radiação (CTDIvol < 3 mGy), sem perder informações diagnósticas.

Influence of reducing antipsychotic drug dose on psychotic symptoms in schizophrenia stabilization period / 中国神经精神疾病杂志

Objective To investigate the effect of reducing antipsychotic dose on clinical symptoms in patients with stable schizophrenia. Methods Seventy-five patients with stable schizophrenia taking olanzapine or risperidone were enrolled. Patients were randomly divided into dose reduction group (37 cases) and maintenance group (38 cases). The dose of the risperidone or olanzapine was gradually reduced by 50％ in the dose reduction group within six months whereas remained unchanged in the maintenance group. The Positive and Negative Symptom Scale (PANSS), Calgary Depression Scale (CDRS), Personal and Social Performance Scale (PSP), Insight and Treatment Attitude Questionnaire (ITAQ) and Extrapyramidal Side Effects Scale (RSESE) were assessed at baseline, 3 months, 6 months and 12 months. Results There were one and two cases dropped out due to the relapse in dose reduction group and in maintenance group, respectively. The recurrence rates were 2.7％ in dose reduction group and 5.3％ in maintenance group (P<0.05). The interaction effects of PANSS positive symptoms, negative symptoms and general pathological symptoms, ITAQ,RSESE, PSP were significant (P<0.05). The main effect of PANSS negative symptoms and PSP group was significant (P<0.05). Compared with the maintenance group, PANSS negative symptoms of the dose reduction group were significantly lower at 6 and 12 months (P<0.05). PSP scores were significantly higher in the dose reduction group than in maintenance group (P<0.05) at 3, 6 and 12 months. Conclusion Reducing the dose of risperidone or olanzapine slowly in patients with stable schizophrenia within six months reduces negative symptoms and adverse reaction, improves social function without increasing positive symptoms.

Low-Tube-Voltage CT Urography Using Low-Concentration-Iodine Contrast Media and Iterative Reconstruction: A Multi-Institutional Randomized Controlled Trial for Comparison with Conventional CT Urography

OBJECTIVE: To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU. MATERIALS AND METHODS: This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated. RESULTS: The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose (5.73 ± 4.04 vs. 8.43 ± 4.38 mSv) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ≥ 3), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group. CONCLUSION: The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.

The Potential Role of Grid-Like Software in Bedside Chest Radiography in Improving Image Quality and Dose Reduction: An Observer Preference Study

OBJECTIVE: To compare the observer preference of image quality and radiation dose between non-grid, grid-like, and grid images. MATERIALS AND METHODS: Each of the 38 patients underwent bedside chest radiography with and without a grid. A grid-like image was generated from a non-grid image using SimGrid software (Samsung Electronics Co. Ltd.) employing deep-learning-based scatter correction technology. Two readers recorded the preference for 10 anatomic landmarks and the overall appearance on a five-point scale for a pair of non-grid and grid-like images, and a pair of grid-like and grid images, respectively, which were randomly presented. The dose area product (DAP) was also recorded. Wilcoxon's rank sum test was used to assess the significance of preference. RESULTS: Both readers preferred grid-like images to non-grid images significantly (p < 0.001); with a significant difference in terms of the preference for grid images to grid-like images (p = 0.317, 0.034, respectively). In terms of anatomic landmarks, both readers preferred grid-like images to non-grid images (p < 0.05). No significant differences existed between grid-like and grid images except for the preference for grid images in proximal airways by two readers, and in retrocardiac lung and thoracic spine by one reader. The median DAP were 1.48 (range, 1.37–2.17) dGy*cm2 in grid images and 1.22 (range, 1.11–1.78) dGy*cm2 in grid-like images with a significant difference (p < 0.001). CONCLUSION: The SimGrid software significantly improved the image quality of non-grid images to a level comparable to that of grid images with a relatively lower level of radiation exposure.

Radiation Dose Reduction without Compromise to Image Quality by Alterations of Filtration and Focal Spot Size in Cerebral Angiography

OBJECTIVE: Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. MATERIALS AND METHODS: Radiation dose and image quality were analyzed by varying the filtration and focal spot size on digital subtraction angiography exposure protocols (1, inherent filtration + large focus; 2, inherent + small; 3, copper + large; 4, copper + small). For the in-vitro analysis, a phantom was used for comparison of radiation dose. For the in-vivo analysis, bilateral paired injections, and patient cohort groups were compared for radiation dose and image quality. Image quality analysis was performed in terms of contrast, sharpness, noise, and overall quality. RESULTS: In the in-vitro analysis, the mean air kerma (AK) and dose area product (DAP)/frame were significantly lower with added copper filtration (protocols 3 and 4). In the in-vivo bilateral paired injections, AK and DAP/frame were significantly lower with filtration, without significant difference in image quality. The patient cohort groups with added filtration (protocols 3 and 4) showed significant reduction of total AK and DAP/patient without compromise to the image quality. Variations in focal spot size showed no significant differences in radiation dose and image quality. CONCLUSION: Addition of filtration for angiographic exposure studies can result in significant total radiation dose reduction without loss of image quality. Focal spot size does not influence radiation dose and image quality. The routine angiographic protocol should be judiciously investigated and implemented.

Attenuation-Based Automatic Kilovoltage Selection and Sinogram-Affirmed Iterative Reconstruction: Effects on Radiation Exposure and Image Quality of Portal-Phase Liver CT

OBJECTIVE: To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver. MATERIALS AND METHODS: We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images. RESULTS: Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001). CONCLUSION: Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

Quantitative Analysis of the Effect of Iterative Reconstruction Using a Phantom: Determining the Appropriate Blending Percentage

PURPOSE: To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT). MATERIALS AND METHODS: The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol. RESULTS: As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture. CONCLUSION: Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture.

Evaluation on image quality and radiation dose of 640-slice CT coronary arteriography with AIDR3D reconstruction algorithm / 重庆医学

Objective To investigate the image quality and radiation dose of 640-slice CT coronary arteriography(CTCA) with adaptive iterative dose reduction three-dimensional (AIDR3D)reconstrucction algoritym.Methods 640-slice CTCA with auto-matic exposure was performed on 84 consecutive patients.The original image data were reconstructed with AIDR3D and the filtered back-projection (FBP)algorithms at the image postprocessing workstation.Two experienced radiologists without knowing clinical information and reconstruction algorithms independently measured and calculated the image noise,signal-to-noise ratio and contrast-to-noise ratio with AIDR3D and FBP reconstruction algorithms.The qualitative image quality was assessed by using the 4-point scale.The radiation dose was calculated based on dose-length product exported on CT scanner.The quantitative and qualitative im-age quality with two kinds of reconstruction algorithm was analyzed statistically.Results The CTCA image noise was (27.20± 4.40)HU with AIDR3D and (60.00±12.40)HU with FBP,which with AIDR3D was decreased by 46.10% than that with FBP;the signal-to-noise ratio was 21.10 ± 5.10 with AIDR3D and 11.40 ± 2.80 with FBP,which with AIDR3D was increased by 84.70% than that with FBP;the contrast-to-noise ratio was 24.70±5.10 with AIDR3D and 13.50±3.20 with FBP,which with AIDR3D was raised by 82.20% than that with FBP,the differences in 3 indexes between the two kinds of reconstruction algorithm were statistically significant(P < 0.05 ).The CTCA qualitative image quality scores of proximal,middle and distal parts with AIDR3D were (3.90±0.30),(3.70±0.50)and (3.60±0.60)respectively,which all were higher than (2.60±0.60),(2.30± 0.60)and (2.10±0.70)with FBP respectively,the differences in 3 items between 2 kinds of algorithm had statistical significance (P <0.05).The total segments which could be used to diagnose the CTCA images with AIDR3D and FBP algorithms were 1 216 segments (96.50%)and 504 segments (40.00%),respectively,the difference had statistical significance(P <0.05).The mean ef-fective radiation dose was (2.10±1.00)mSv.Conclusion 640-slice CTCA with AIDR3D reconstruction algorithm not only signifi-cantly reduces the image noise than the conventional FBP algorithm,improves the quantitative and qualitative image quality,but also decreases the effective radiation dose.

Caracterização de uma blindagem de chumbo protetora de mamas para redução de dose em exames de tomografia computadorizada / Characterization of a lead breast shielding for dose reduction in computed tomography

Objetivo: Diversos estudos foram publicados quanto ao uso de blindagens de bismuto para proteção de mamas em exames de tomografia computadorizada (TC), e até a redação deste artigo encontrou-se apenas uma publicação sobre blindagens de bário. O objetivo deste estudo foi caracterizar, pela primeira vez, uma manta plumbífera para proteção de mamas. Materiais e Métodos: Foram avaliadas a redução percentual da dose e a influência desta blindagem em parâmetros quantitativos da imagem. Medidas de dose foram feitas em um equipamento de TC com auxílio de fantomas específicos e detectores de radiação. Um software de processamento auxiliou na análise qualitativa, que consistiu em avaliar a variação no número médio de TC e do ruído nas imagens. Resultados: Uma redução de dose na entrada em até 30% e do CTDIvol em até 17% foi encontrada. Como previsto na literatura, a presença do algodão como objeto espaçador reduziu significativamente os artefatos presentes na imagem. Em todas as medidas realizadas foi constatado aumento do número médio de TC e do ruído das imagens na presença da manta. Conclusão: Como esperado, os dados encontrados para a blindagem com chumbo foram da mesma ordem daqueles encontrados na literatura para blindagem com bismuto. .

Objective: Several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding. Materials and Methods: The percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images. Results: The authors observed a reduction in entrance dose by 30% and in CTDIvol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding. Conclusion: As expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding. .

Temporal Trends in Radiation Exposure and Utilization of Coronary CT Angiography, SPECT, and Invasive Coronary Angiography.

Background: The use of noninvasive medical imaging has increased over the past decade at a cost of significant lifetime radiation exposure to study subjects. We report the implementation of radiation dose reduction methods and associated reduction in ionizing radiation exposure with Coronary Computed Tomography Angiography (CCTA) over time. Methods: Radiation doses and total number of studies performed were evaluated constantly from January 2010 to September 2012 for CCTA (N=2613), as well as Single photon emission computed tomography (SPECT, N=8060) part of an ongoing effort to minimize radiation exposure. Analysis of variance was used to evaluate the radiation exposure reduction among modalities. We compared CCTA radiation doses in the era of retrospective protocols coupled with dose modulation (40%-80%phase) using Siemens® 64-slice Dual Source technology, with prospective scanning on the same equipment, as well as radiation doses on the newer Siemens® Flash Equipment and the implementation of nursing/technologist aggressively driven protocol for heart rate control and image acquisition independent of imaging provider presence during acquisition. Results: The radiation dose reduction with implementation of multiple measures of radiation reduction to include physician independent-technician driven CCTA protocol resulted in a reduction from mean of 9.85±5.96 (median 8.8mSv) to mean of 3.00±2.53(median 2.1mSv) (p<0.0001). CCTA radiation dose has decreased by 69.2% since January of 2010 while SPECT radiation dose remained constant at 14mSv (p<0.0001). Conclusion: Continued advances in software and hardware technology, combined with “physician independent-technician driven” CCTA protocol have drastically reduced radiation dosing in CCTA to annual background radiation exposure, while maximizing the benefit of the study and without sacrificing patient safety.

Cardiac dose reduction with breathing adapted radiotherapy using self respiration monitoring system for left-sided breast cancer

PURPOSE: To quantify the cardiac dose reduction during breathing adapted radiotherapy using Real-time Position Management (RPM) system in the treatment of left-sided breast cancer. MATERIALS AND METHODS: Twenty-two patients with left-sided breast cancer underwent CT scans during breathing maneuvers including free breathing (FB), deep inspiration breath-hold (DIBH), and end inspiration breath-hold (EIBH). The RPM system was used to monitor respiratory motion, and the in-house self respiration monitoring (SRM) system was used for visual feedback. For each scan, treatment plans were generated and dosimetric parameters from DIBH and EIBH plans were compared to those of FB plans. RESULTS: All patients completed CT scans with different breathing maneuvers. When compared with FB plans, DIBH plans demonstrated significant reductions in irradiated heart volume and the heart V25, with the relative reduction of 71% and 70%, respectively (p < 0.001). EIBH plans also resulted in significantly smaller irradiated heart volume and lower heart V25 than FB plans, with the relative reduction of 39% and 37%, respectively (p = 0.002). Despite of significant expansion of lung volume using inspiration breath-hold, there were no significant differences in left lung V25 among the three plans. CONCLUSION: In comparison with FB, both DIBH and EIBH plans demonstrated a significant reduction of radiation dose to the heart. In the training course, SRM system was useful and effective in terms of positional reproducibility and patient compliance.

Adaptive Iterative Dose Reduction Algorithm in CT: Effect on Image Quality Compared with Filtered Back Projection in Body Phantoms of Different Sizes

OBJECTIVE: To evaluate the impact of the adaptive iterative dose reduction (AIDR) three-dimensional (3D) algorithm in CT on noise reduction and the image quality compared to the filtered back projection (FBP) algorithm and to compare the effectiveness of AIDR 3D on noise reduction according to the body habitus using phantoms with different sizes. MATERIALS AND METHODS: Three different-sized phantoms with diameters of 24 cm, 30 cm, and 40 cm were built up using the American College of Radiology CT accreditation phantom and layers of pork belly fat. Each phantom was scanned eight times using different mAs. Images were reconstructed using the FBP and three different strengths of the AIDR 3D. The image noise, the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) of the phantom were assessed. Two radiologists assessed the image quality of the 4 image sets in consensus. The effectiveness of AIDR 3D on noise reduction compared with FBP were also compared according to the phantom sizes. RESULTS: Adaptive iterative dose reduction 3D significantly reduced the image noise compared with FBP and enhanced the SNR and CNR (p < 0.05) with improved image quality (p < 0.05). When a stronger reconstruction algorithm was used, greater increase of SNR and CNR as well as noise reduction was achieved (p < 0.05). The noise reduction effect of AIDR 3D was significantly greater in the 40-cm phantom than in the 24-cm or 30-cm phantoms (p < 0.05). CONCLUSION: The AIDR 3D algorithm is effective to reduce the image noise as well as to improve the image-quality parameters compared by FBP algorithm, and its effectiveness may increase as the phantom size increases.

Clinical efficacy of radical intensity-modulated radiotherapy combined with reduction in dose of prophylactic irradiation in treatment of stage Ⅲ small cell lung cancer / 中华放射肿瘤学杂志

Objective To evaluate the clinical efficacy and toxicities of radical intensity-modulated radiotherapy (IMRT) combined with reduction in dose of prophylactic irradiation in the treatment of stage Ⅲ small cell lung cancer (SCLC).Methods A retrospective analysis was performed on the clinical data of 40 patients with stage Ⅲ SCLC who were admitted from January 2010 to August 2012.The prescribed dose was 60 Gy in 30 fractions to the primary gross tumor volume and was 54 Gy in 30 fractions to the planning target volume.All patients received induction chemotherapy,31 patients received adjuvant chemotherapy,and 22 patients received concurrent chemoradiotherapy;the platinum-based chemotherapy combined with etoposide or teniposide was adopted.Prophylactic cranial irradiation (25 Gy in 10 fractions) was administered to 17 patients.The short-term tumor response was evaluated by RECIST 1.0,and radiation-related toxicities were assessed by CTCAE 4.0.Overall survival (OS),local recurrence-free survival (LRFS),and progression-free survival (PFS) were calculated by Kaplan-Meier method.Results The short-term tumor response rate was 98％.The follow-up rate was 100％.Twenty-two patients were followed up for at least 2 years.The 1-and 2-year OS rates were 84％ and 48％,respectively; the LRFS rates were 89％ and 85％,respectively; the PFS rates were 61％ and 41％,respectively.Grade 0-1 radiation-related pneumonia was observed in 65％(26/40) of all patients,grade 2 in 25％ (10/40),grade 3 in 5％ (2/40),and grade 5 in 5％ (2/40).Grade 0-1 radiation-related esophagitis was observed in 53％ (21/40) of all patients,grade 2 in 43％ (17/40),and grade 3 in 5 ％ (2/40).Conclusions Preliminary results from this study suggested that IMRT combined with reduction in dose of prophylactic irradiation is safe and effective in patients with stage Ⅲ SCLC and is worth further evaluation in a large,prospective,randomized study.

Radiation Dose Reduction via Sinogram Affirmed Iterative Reconstruction and Automatic Tube Voltage Modulation (CARE kV) in Abdominal CT

OBJECTIVE: To evaluate the feasibility of sinogram-affirmed iterative reconstruction (SAFIRE) and automated kV modulation (CARE kV) in reducing radiation dose without increasing image noise for abdominal CT examination. MATERIALS AND METHODS: This retrospective study included 77 patients who received CT imaging with an application of CARE kV with or without SAFIRE and who had comparable previous CT images obtained without CARE kV or SAFIRE, using the standard dose (i.e., reference mAs of 240) on an identical CT scanner and reconstructed with filtered back projection (FBP) within 1 year. Patients were divided into two groups: group A (33 patients, CT scanned with CARE kV); and group B (44 patients, scanned after reducing the reference mAs from 240 to 170 and applying both CARE kV and SAFIRE). CT number, image noise for four organs and radiation dose were compared among the two groups. RESULTS: Image noise increased after CARE kV application (p or = 0.108). Effective doses decreased by 19.4% and 41.3% for groups A and B, respectively (all, p < 0.001) after application of CARE kV with or without SAFIRE. CONCLUSION: Combining CARE kV, reduction of mAs from 240 to 170 mAs and noise reduction by applying SAFIRE strength 3 or 4 reduced the radiation dose by 41.3% without increasing image noise compared with the standard-dose FBP images.

CT Radiation Dose Optimization and Estimation: an Update for Radiologists

In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.

Radiation Dose Reduction of Chest CT with Iterative Reconstruction in Image Space - Part II: Assessment of Radiologists' Preferences Using Dual Source CT

OBJECTIVE: To evaluate the impact of radiation dose and reconstruction algorithms on radiologists' preferences, and whether an iterative reconstruction in image space (IRIS) can be used for dose reduction in chest CT. MATERIALS AND METHODS: Standard dose chest CT (SDCT) in 50 patients and low dose chest CT (LDCT) in another 50 patients were performed, using a dual-source CT, with 120 kVp and same reference mAs (50 mAs for SDCT and 25 mAs for LDCT) employed to both tubes by modifying the dual-energy scan mode. Full-dose data were obtained by combining the data from both tubes and half-dose data were separated from one tube. These were reconstructed by using a filtered back projection (FBP) and IRIS: full-dose FBP (F-FBP); full-dose IRIS (F-IRIS); half-dose FBP (H-FBP) and half-dose IRIS (H-IRIS). Ten H-IRIS/F-IRIS, 10 H-FBP/H-IRIS, 40 F-FBP/F-IRIS and 40 F-FBP/H-IRIS pairs of each SDCT and LDCT were randomized. The preference for clinical usage was determined by two radiologists with a 5-point-scale system for the followings: noise, contrast, and sharpness of mediastinum and lung. RESULTS: Radiologists preferred IRIS over FBP images in the same radiation dose for the evaluation of the lungs in both SDCT (p = 0.035) and LDCT (p < 0.001). When comparing between H-IRIS and F-IRIS, decreased radiation resulted in decreased preference. Observers preferred H-IRIS over F-FBP for the lungs in both SDCT and LDCT, even with reduced radiation dose by half in IRIS image (p < 0.05). CONCLUSION: Radiologists' preference may be influenced by both radiation dose and reconstruction algorithm. According to our preliminary results, dose reduction at 50% with IRIS may be feasible for lung parenchymal evaluation.