Exploring the potential of intermetallic alloys as implantable biomaterials: A comprehensive review

This review delves into the utilization of intermetallic alloys (IMAs) as advanced biomaterials for medical implants, scrutinizing their conceptual framework, fabrication challenges, and diverse manufacturing techniques such as casting, powder metallurgy, and additive manufacturing. Manufacturing techniques such as casting, powder metallurgy, additive manufacturing, and injection molding are discussed, with specific emphasis on achieving optimal grain sizes, surface roughness, and mechanical properties. Post-treatment methods aimed at refining surface quality, dimensional precision, and mechanical properties of IMAs are explored, including the use of heat treatments to enhance biocompatibility and corrosion resistance. The review presents an in-depth examination of IMAs-based implantable biomaterials, covering lab-scale developments and commercial-scale implants. Specific IMAs such as Nickel Titanium, Titanium Aluminides, Iron Aluminides, Magnesium-based IMAs, Zirconium-based IMAs, and High-entropy alloys (HEAs) are highlighted, with detailed discussions on their mechanical properties, including strength, elastic modulus, and corrosion resistance. Future directions are outlined, with an emphasis on the anticipated growth in the orthopedic devices market and the role of IMAs in meeting this demand. The potential of porous IMAs in orthopedics is explored, with emphasis on achieving optimal pore sizes and distributions for enhanced osseointegration. The review concludes by highlighting the ongoing need for research and development efforts in IMAs technologies, including advancements in design and fabrication techniques.

Automatic identification of hypertension and assessment of its secondary effects using artificial intelligence: A systematic review (2013-2023)

Artificial Intelligence (AI) techniques are increasingly used in computer-aided diagnostic tools in medicine. These techniques can also help to identify Hypertension (HTN) in its early stage, as it is a global health issue. Automated HTN detection uses socio-demographic, clinical data, and physiological signals. Additionally, signs of secondary HTN can also be identified using various imaging modalities. This systematic review examines related work on automated HTN detection. We identify datasets, techniques, and classifiers used to develop AI models from clinical data, physiological signals, and fused data (a combination of both). Image-based models for assessing secondary HTN are also reviewed. The majority of the studies have primarily utilized single-modality approaches, such as biological signals (e.g., electrocardiography, photoplethysmography), and medical imaging (e.g., magnetic resonance angiography, ultrasound). Surprisingly, only a small portion of the studies (22 out of 122) utilized a multi-modal fusion approach combining data from different sources. Even fewer investigated integrating clinical data, physiological signals, and medical imaging to understand the intricate relationships between these factors. Future research directions are discussed that could build better healthcare systems for early HTN detection through more integrated modeling of multi-modal data sources.

Development and physicochemical characterization of a biodegradable microspheres formulation loaded with samarium-153 and doxorubicin for chemo-radioembolization of liver tumours

Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are promising treatments for unresectable liver tumours. Some recent studies suggested that combining TACE and TARE in one treatment course might improve treatment efficacy through synergistic cytotoxicity effects. Nonetheless, current formulations do not facilitate a combination of chemo- and radio-embolic agents in one delivery system. Therefore, this study aimed to synthesise a hybrid biodegradable microsphere loaded with both radioactive agent, samarium-153 (153 Sm) and chemotherapeutic drug, doxorubicin (Dox) for potential radio-chemoembolization of advanced liver tumours. 152 Sm and Dox-loaded polyhydroxybutyrate-co-3-hydroxyvalerate (PHBV) microspheres were prepared using water-in-oil-in-water solvent evaporation method. The microspheres were then sent for neutron activation in a neutron flux of 2 × 1012  n/cm2 /s. The physicochemical properties, radioactivity, radionuclide purity, 153 Sm retention efficiency, and Dox release profile of the Dox-153 Sm-PHBV microspheres were analysed. In addition, in vitro cytotoxicity of the formulation was tested using MTT assay on HepG2 cell line at 24 and 72 h. The mean diameter of the Dox-153 Sm-PHBV microspheres was 30.08 ± 2.79 μm. The specific radioactivity was 8.68 ± 0.17 GBq/g, or 177.69 Bq per microsphere. The 153 Sm retention efficiency was more than 99%, tested in phosphate-buffered saline (PBS) and human blood plasma over 26 days. The cumulative release of Dox from the microspheres after 41 days was 65.21 ± 1.96% and 29.96 ± 0.03% in PBS solution of pH 7.4 and pH 5.5, respectively. The Dox-153 Sm-PHBV microspheres achieved a greater in vitro cytotoxicity effect on HepG2 cells (85.73 ± 3.63%) than 153 Sm-PHBV (70.03 ± 5.61%) and Dox-PHBV (74.06 ± 0.78%) microspheres at 300 μg/mL at 72 h. In conclusion, a novel biodegradable microspheres formulation loaded with chemotherapeutic drug (Dox) and radioactive agent (153 Sm) was successfully developed in this study. The formulation fulfilled all the desired physicochemical properties of a chemo-radioembolic agent and achieved better in vitro cytotoxicity on HepG2 cells. Further investigations are needed to evaluate the biosafety, radiation dosimetry, and synergetic anticancer properties of the formulation.

Understanding Factors Associated with Motivation to Quit Vaping among Vapers in the Federal Territory of Kuala Lumpur, Malaysia

The prevalence of vaping worldwide is showing an upward trend. This study aimed to determine the factors associated with motivation to quit vaping among vapers in the Federal Territory of Kuala Lumpur, Malaysia, through a cross-sectional, purposive sampling study. Respondents were required to complete a questionnaire consisting of vapers' sociodemographic questions, habitual behavioral pattern questions, the e-Fagerström Test of Nicotine Dependence, the Glover-Nilsson Smoking Behavioral Dependence Questionnaire, perception questions, motivation to quit questions, and withdrawal symptom questions. A total of 311 vapers participated in this study. The majority of the vapers were male (84.6%), younger (18-25 years) (55.3%), and with monthly income less than RM 4000 (USD 868; 83.9%). The level of motivation to quit vaping was found to have a significant association with the perception of vaping being as satisfying as cigarette smoking (p = 0.006) and mild to very strong nicotine dependence (p = 0.001). Participants who recorded moderate and strong habitual vaping behaviors had lower odds of having high motivation to quit vaping compared to those recording slight habitual behaviors (OR = 0.279, 95%CI(0.110-0.708), p = 0.007 and OR = 0.185, 95%CI(0.052-0.654), p = 0.009, respectively). Factors associated with higher motivation to quit vaping could be explored to gain better understanding of how to increase their motivation level for future quit attempts.

Patient-Specific 3D-Printed Low-Cost Models in Medical Education and Clinical Practice

3D printing has been increasingly used for medical applications with studies reporting its value, ranging from medical education to pre-surgical planning and simulation, assisting doctor-patient communication or communication with clinicians, and the development of optimal computed tomography (CT) imaging protocols. This article presents our experience of utilising a 3D-printing facility to print a range of patient-specific low-cost models for medical applications. These models include personalized models in cardiovascular disease (from congenital heart disease to aortic aneurysm, aortic dissection and coronary artery disease) and tumours (lung cancer, pancreatic cancer and biliary disease) based on CT data. Furthermore, we designed and developed novel 3D-printed models, including a 3D-printed breast model for the simulation of breast cancer magnetic resonance imaging (MRI), and calcified coronary plaques for the simulation of extensive calcifications in the coronary arteries. Most of these 3D-printed models were scanned with CT (except for the breast model which was scanned using MRI) for investigation of their educational and clinical value, with promising results achieved. The models were confirmed to be highly accurate in replicating both anatomy and pathology in different body regions with affordable costs. Our experience of producing low-cost and affordable 3D-printed models highlights the feasibility of utilizing 3D-printing technology in medical education and clinical practice.

Swin-textural: A novel textural features-based image classification model for COVID-19 detection on chest computed tomography

Background

Chest computed tomography (CT) has a high sensitivity for detecting COVID-19 lung involvement and is widely used for diagnosis and disease monitoring. We proposed a new image classification model, swin-textural, that combined swin-based patch division with textual feature extraction for automated diagnosis of COVID-19 on chest CT images. The main objective of this work is to evaluate the performance of the swin architecture in feature engineering.

Material and method

We used a public dataset comprising 2167, 1247, and 757 (total 4171) transverse chest CT images belonging to 80, 80, and 50 (total 210) subjects with COVID-19, other non-COVID lung conditions, and normal lung findings. In our model, resized 420 × 420 input images were divided using uniform square patches of incremental dimensions, which yielded ten feature extraction layers. At each layer, local binary pattern and local phase quantization operations extracted textural features from individual patches as well as the undivided input image. Iterative neighborhood component analysis was used to select the most informative set of features to form ten selected feature vectors and also used to select the 11th vector from among the top selected feature vectors with accuracy >97.5%. The downstream kNN classifier calculated 11 prediction vectors. From these, iterative hard majority voting generated another nine voted prediction vectors. Finally, the best result among the twenty was determined using a greedy algorithm.

Results

Swin-textural attained 98.71% three-class classification accuracy, outperforming published deep learning models trained on the same dataset. The model has linear time complexity.

Conclusions

Our handcrafted computationally lightweight swin-textural model can detect COVID-19 accurately on chest CT images with low misclassification rates. The model can be implemented in hospitals for efficient automated screening of COVID-19 on chest CT images. Moreover, findings demonstrate that our presented swin-textural is a self-organized, highly accurate, and lightweight image classification model and is better than the compared deep learning models for this dataset.

A Systematic Review of Molecular Hydrogen Therapy in Cancer Management

BACKGROUND

Cancer remains a challenging target to cure, with present therapeutic methods unable to exhibit restorative outcomes without causing severe negative effects. Molecular hydrogen (H2) has been reported to be a promising adjunctive therapy for cancer treatment, having the capability to induce anti-proliferative, anti-oxidative, pro-apoptotic and anti-tumoural effects. This review summarises the findings from various articles on the mechanism, treatment outcomes, and overall effectiveness of H2 therapy on cancer management.

METHODS

Using Cochrane, PubMed, and Google Scholar as the search engines, full-text articles in the scope of the study, written in English and within 10 years of publication were selected.

RESULTS

Out of the 677 articles, 27 articles fulfilled the eligibility criteria, where data was compiled into a table, outlining the general characteristics and findings. Throughout the different forms of H2 administration, study design and types of cancers reported, outcomes were found to be consistent.

CONCLUSION

From our analysis, H2 plays a promising therapeutic role as an independent therapy as well as an adjuvant in combination therapy, resulting in an overall improvement in survivability, quality of life, blood parameters, and tumour reduction. Although more comprehensive research is needed, given the promising outcomes, H2 is worth considering for use as a complement to current cancer therapy.

Utilizing 3D Slicer to incorporate tomographic images into GATE Monte Carlo simulation for personalized dosimetry in yttrium-90 radioembolization

PURPOSE

Monte Carlo (MC) simulation is an important technique that can help design advanced and challenging experimental setups. GATE (Geant4 application for tomographic emission) is a useful simulation toolkit for applications in nuclear medicine. Transarterial radioembolization is a treatment for liver cancer, where microspheres embedded with yttrium-90 (⁹⁰ Y) are administered intra-arterially to the tumor. Personalized dosimetry for this treatment may provide higher dosimetry accuracy compared to the conventional partition model (PM) calculation. However, incorporation of three-dimensional tomographic input data into MC simulation is an intricate process. In this article, 3D Slicer, free and open-source software, was utilized for the incorporation of patient tomographic images into GATE to demonstrate the feasibility of personalized dosimetry in hepatic radioembolization with ⁹⁰ Y.

METHODS

In this article, the steps involved in importing, segmenting, and registering tomographic images using 3D Slicer were thoroughly described, before importing them into GATE for MC simulation. The absorbed doses estimated using GATE were then compared with that of PM. SlicerRT, a 3D Slicer extension, was then used to visualize the isodose from the MC simulation.

RESULTS

A workflow diagram consisting of all the steps taken in the utilization of 3D Slicer for personalized dosimetry in ⁹⁰ Y radioembolization has been presented in this article. In comparison to the MC simulation, the absorbed doses to the tumor and normal liver were overestimated by PM by 105.55% and 20.23%, respectively, whereas for lungs, the absorbed dose estimated by PM was underestimated by 25.32%. These values were supported by the isodose distribution obtained via SlicerRT, suggesting the presence of beta particles outside the volumes of interest. These findings demonstrate the importance of personalized dosimetry for a more accurate absorbed dose estimation compared to PM.

CONCLUSION

The methodology provided in this study can assist users (especially students or researchers who are new to MC simulation) in navigating intricate steps required in the importation of tomographic data for MC simulation. These steps can also be utilized for other radiation therapy related applications, not necessarily limited to internal dosimetry.

3D-Printed Coronary Plaques to Simulate High Calcification in the Coronary Arteries for Investigation of Blooming Artifacts

The diagnostic value of coronary computed tomography angiography (CCTA) is significantly affected by high calcification in the coronary arteries owing to blooming artifacts limiting its accuracy in assessing the calcified plaques. This study aimed to simulate highly calcified plaques in 3D-printed coronary models. A combination of silicone + 32.8% calcium carbonate was found to produce 800 HU, representing extensive calcification. Six patient-specific coronary artery models were printed using the photosensitive polyurethane resin and a total of 22 calcified plaques with diameters ranging from 1 to 4 mm were inserted into different segments of these 3D-printed coronary models. The coronary models were scanned on a 192-slice CT scanner with 70 kV, pitch of 1.4, and slice thickness of 1 mm. Plaque attenuation was measured between 1100 and 1400 HU. Both maximum-intensity projection (MIP) and volume rendering (VR) images (wide and narrow window widths) were generated for measuring the diameters of these calcified plaques. An overestimation of plaque diameters was noticed on both MIP and VR images, with measurements on the MIP images close to those of the actual plaque sizes (<10% deviation), and a large measurement discrepancy observed on the VR images (up to 50% overestimation). This study proves the feasibility of simulating extensive calcification in coronary arteries using a 3D printing technique to develop calcified plaques and generate 3D-printed coronary models.

Health management during COVID-19 pandemic-contribution of women health informaticians, medical physicists and veterinarians from Bangladesh and Malaysia during the world crisis

This article aims to highlight some of the contributions from Bangladeshi and Malaysian women scientists in the fields of health informatics, medical physics and biomedical engineering, and veterinary science in combating the COVID-19 world crisis. The status of COVID-19 situations in Bangladesh and Malaysia in respect to global scenario, some relevant government policies, lessons learnt from previous pandemics, socio-economic impacts of COVID-19, the impact on healthcare system and health management approaches taken by individual/institutional research group led by women scientists during the COVID-19 pandemic have been discussed and demonstrated in this article. These promising activities and initiatives will eventually motivate other women in science and extend their roles from laboratory to society in more aspects.

Laser-heated needle for biopsy tract ablation: In vivo study of rabbit liver biopsy

PURPOSE

To investigate the efficacy of a newly-developed laser-heated core biopsy needle in the thermal ablation of biopsy tract to reduce hemorrhage after biopsy using in vivo rabbit's liver model.

MATERIALS AND METHODS

Five male New Zealand White rabbits weighed between 1.5 and 4.0 kg were anesthetized and their livers were exposed. 18 liver biopsies were performed under control group (without tract ablation, n = 9) and study group (with tract ablation, n = 9) settings. The needle insertion depth (~3 cm) and rate of retraction (~3 mm/s) were fixed in all the experiments. For tract ablation, three different needle temperatures (100, 120 and 150 °C) were compared. The blood loss at each biopsy site was measured by weighing the gauze pads before and after blood absorption. The rabbits were euthanized immediately and the liver specimens were stained with hematoxylin-eosin (H&E) for further histopathological examination (HPE).

RESULTS

The average blood loss in the study group was reduced significantly (p < 0.05) compared to the control group. The highest percentage of bleeding reduction was observed at the needle temperature of 150 °C (93.8%), followed by 120 °C (85.8%) and 100 °C (84.2%). The HPE results show that the laser-heated core biopsy needle was able to cause lateral coagulative necrosis up to 14 mm diameter along the ablation tract.

CONCLUSION

The laser-heated core biopsy needle reduced hemorrhage up to 93.8% and induced homogenous coagulative necrosis along the ablation tract in the rabbits' livers. This could potentially reduce the risk of tumor seeding in clinical settings.

Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine.

Comparison of deep and moderate neuromuscular blockade in microwave ablation of liver tumours: a randomized-controlled clinical trial

Microwave ablation (MWA) is gaining popularity for the treatment of small primary hepatocellular carcinoma and metastatic lesions especially if patients are not candidates for surgical resection. Deep neuromuscular blockade (DMB) is perceived to improve surgical working conditions compared to moderate neuromuscular blockade (MMB) but no studies have examined the same benefits in MWA of liver tumours. This study aimed to compare the clinical outcomes of DMB and MMB in MWA of liver tumours in terms of liver excursion, performance scores by the interventional radiologists and patients, requirements of additional muscle relaxants and complications. 50 patients were recruited and 45 patients (22 in MMB group, 23 in DMB group) completed the study. The mean liver excursion for the MMB group (1.42 ± 1.83 mm) was significantly higher than the DMB group (0.26 ± 0.38 mm) (p = 0.001). The mean Leiden-Surgical Rating Scale (L-SRS) rated by the two interventional radiologists were 4.5 ± 0.59 and 3.6 ± 0.85 for the DMB and MMB groups, respectively (p = 0.01). There was also statistically significant difference on patient satisfaction scores (0–10: Extremely Dissatisfied–Extremely Satisfied) between DMB (8.74 ± 1.1) and MMB (7.86 ± 1.25) groups (p = 0.01). 5 patients from MMB group and none from DMB group required bolus relaxant during the MWA procedure. Adverse events were also noted to be more severe in the MMB group. In conclusion, DMB significantly reduced liver excursion and movement leading to improved accuracy, safety and success in ablating liver tumour.

Sonographic renal length and volume of normal Thai children versus their Chinese and Western counterparts

BACKGROUND

Renal size is an important indicator in the diagnosis of renal diseases and urinary tract infections in children.

PURPOSE

The purpose of this study is twofold. First, it aimed to measure the renal length and calculate the renal volume of normal Thai children using 2-dimensional ultrasonography (2D-US) and study their correlations with somatic parameters. Second, it aimed to compare the age-specific renal size of normal Thai children with the published data of their Western and Chinese counterparts.

METHODS

A total of 321 children (150 boys, 171 girls; age, 6-15 years) with a normal renal profile were prospectively recruited. All subjects underwent 2D-US by an experienced pediatric radiologist and the renal length, width, and depth were measured. Renal volume was calculated using the ellipsoid formula as recommended. The data were compared between the left and right kidneys, the sexes, and various somatic parameters. The age-specific renal lengths were compared using a nomogram derived from a Western cohort that is currently referred by many Thailand hospitals, while the renal volumes were compared with the published data of a Chinese cohort.

RESULTS

No statistically significant difference (P<0.05) was found between sexes or the right and left kidneys. The renal sizes had strong correlations with height, weight, body surface area, and age but not with body mass index. The renal length of the Thai children was moderately correlated (r=0.59) with that of the Western cohort, while the age-specific renal volume was significantly smaller (P<0.05) than that of the Chinese children.

CONCLUSION

Therefore, we concluded that the age-specific renal length and volume obtained by 2D-US would vary between children in different regions and may not be suitably used as an international standard for diagnosis, although further studies may be needed to confirm our findings.

Diagnostic accuracy of digital breast tomosynthesis in combination with 2D mammography for the characterisation of mammographic abnormalities

This study aims to assess the diagnostic accuracy of digital breast tomosynthesis in combination with full field digital mammography (DBT + FFDM) in the charaterisation of Breast Imaging-reporting and Data System (BI-RADS) category 3, 4 and 5 lesions. Retrospective cross-sectional study of 390 patients with BI-RADS 3, 4 and 5 mammography with available histopathology examination results were recruited from in a single center of a multi-ethnic Asian population. 2 readers independently reported the FFDM and DBT images and classified lesions detected (mass, calcifications, asymmetric density and architectural distortion) based on American College of Radiology-BI-RADS lexicon. Of the 390 patients recruited, 182 malignancies were reported. Positive predictive value (PPV) of cancer was 46.7%. The PPV in BI-RADS 4a, 4b, 4c and 5 were 6.0%, 38.3%, 68.9%, and 93.1%, respectively. Among all the cancers, 76% presented as masses, 4% as calcifications and 20% as asymmetry. An additional of 4% of cancers were detected on ultrasound. The sensitivity, specificity, PPV and NPV of mass lesions detected on DBT + FFDM were 93.8%, 85.1%, 88.8% and 91.5%, respectively. The PPV for calcification is 61.6% and asymmetry is 60.7%. 81.6% of cancer detected were invasive and 13.3% were in-situ type. Our study showed that DBT is proven to be an effective tool in the diagnosis and characterization of breast lesions and supports the current body of literature that states that integrating DBT to FFDM allows good characterization of breast lesions and accurate diagnosis of cancer.

Teaching and learning of postgraduate medical physics using Internet-based e-learning during the COVID-19 pandemic - A case study from Malaysia

PURPOSE

We present the implementation of e-learning in the Master of Medical Physics programme at the University of Malaya during a partial lockdown from March to June 2020 due to the COVID-19 pandemic.

METHODS

Teaching and Learning (T&L) activities were conducted virtually on e-learning platforms. The students' experience and feedback were evaluated after 15 weeks.

RESULTS

We found that while students preferred face-to-face, physical teaching, they were able to adapt to the new norm of e-learning. More than 60% of the students agreed that pre-recorded lectures and viewing videos of practical sessions, plus answering short questions, were beneficial. Certain aspects, such as hands-on practical and clinical experience, could never be replaced. The e-learning and study-from-home environment accorded a lot of flexibility. However, students also found it challenging to focus because of distractions, lack of engagement and mental stress. Technical problems, such as poor Internet connectivity and limited data plans, also compounded the problem.

CONCLUSION

We expect e-learning to prevail in future. Hybrid learning strategies, which includes face-to-face classes and e-learning, will become common, at least in the medical physics programme of the University of Malaya even after the pandemic.

Neutron-activated theranostic radionuclides for nuclear medicine

Theranostics in nuclear medicine refers to personalized patient management that involves targeted therapy and diagnostic imaging using a single or combination of radionuclide (s). The radionuclides emit both alpha (α) or beta (β^-) particles and gamma (γ) rays which possess therapeutic and diagnostic capabilities, respectively. However, the production of these radionuclides often faces difficulties due to high cost, complexity of preparation methods and that the products are often sourced far from the healthcare facilities, hence losing activity due to radioactive decay during transportation. Subject to the availability of a nuclear reactor within an accessible distance from healthcare facilities, neutron activation is the most practical and cost-effective route to produce radionuclides suitable for theranostic purposes. Holmium-166 (¹⁶⁶Ho), Lutetium-177 (¹⁷⁷Lu), Rhenium-186 (¹⁸⁶Re), Rhenium-188 (¹⁸⁸Re) and Samarium-153 (¹⁵³Sm) are some of the most promising neutron-activated radionuclides that are currently in clinical practice and undergoing clinical research for theranostic applications. The aim of this paper is to review the physical characteristics, current clinical applications and future prospects of these neutron activated radionuclides in theranostics. The production, physical properties, validated clinical applications and clinical studies for each neutron-activated radionuclide suitable for theranostic use in nuclear medicine are reviewed in this paper.

Marrow Fat Content and Composition in β-Thalassemia: A Study using 1 H-MRS

BACKGROUND

β-thalassemia is a genetic disease that causes abnormal production of red blood cells (ineffective erythropoiesis, IE). IE is a condition known to change bone marrow composition.

PURPOSE

To evaluate the effect of IE on the marrow fat content and fat unsaturation levels in the proximal femur using ¹ H-MRS.

STUDY TYPE

Prospective.

SUBJECTS

Twenty-three subjects were included in this study, seven control and 16 β-thalassemia subjects.

FIELD STRENGTH/SEQUENCE

3.0T; stimulated echo acquisition Mode (STEAM); magnetic resonance spectroscopy (MRS) sequence.

ASSESSMENT

Multiecho MRS scans were performed in four regions of the proximal left femur of each subject, that is, diaphysis, femoral neck, femoral head, and greater trochanter. The examined regions were grouped into red (diaphysis and femoral neck) and yellow marrow regions (femoral head and greater trochanter).

STATISTICAL TESTS

The Jonckheere-Terpstra test was used to evaluate the impact of increasing disease severity on bone marrow fat fraction (BMFF), marrow conversion index, and fat unsaturation index (UI). Pairwise comparison analysis was performed when a significant trend (P < 0.05) was found. K-means clustering analysis was used to examine the clusters observed when BMFF in the red and yellow regions were studied (diaphysis against greater trochanter).

RESULTS

BMFF showed a significant decreasing trend with increasing disease severity in both red (T_JT = 109.00, z = -4.414, P < 0.05) and yellow marrow regions (T_JT = 108.00, z = -4.438, P < 0.05). The opposite trend was observed in UI in both bone marrow regions (red marrow: T_JT = 180.5, z = 3.515, P < 0.05; yellow marrow: T_JT = 155.0, z = 2.282, P = 0.05). Three distinct forms of marrow adipogenesis were found when plotting BMFF diaphysis against BMFF greater trochanter: 1) normal (centroid: 80.4%, 66.6%), 2) partial disruption (centroid: 51.1%, 16.6%), and 3) total disruption (centroid: 2.6%, 1.6%).

DATA CONCLUSION

β-thalassemia is associated with decreased marrow fat, and increased marrow fat unsaturation level.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 3.

Development of patient-specific 3D-printed breast phantom using silicone and peanut oils for magnetic resonance imaging

Background

Despite increasing reports of 3D printing in medical applications, the use of 3D printing in breast imaging is limited, thus, personalized 3D-printed breast model could be a novel approach to overcome current limitations in utilizing breast magnetic resonance imaging (MRI) for quantitative assessment of breast density. The aim of this study is to develop a patient-specific 3D-printed breast phantom and to identify the most appropriate materials for simulating the MR imaging characteristics of fibroglandular and adipose tissues.

Methods

A patient-specific 3D-printed breast model was generated using 3D-printing techniques for the construction of the hollow skin and fibroglandular region shells. Then, the T1 relaxation times of the five selected materials (agarose gel, silicone rubber with/without fish oil, silicone oil, and peanut oil) were measured on a 3T MRI system to determine the appropriate ones to represent the MR imaging characteristics of fibroglandular and adipose tissues. Results were then compared to the reference values of T1 relaxation times of the corresponding tissues: 1,324.42±167.63 and 449.27±26.09 ms, respectively. Finally, the materials that matched the T1 relaxation times of the respective tissues were used to fill the 3D-printed hollow breast shells.

Results

The silicone and peanut oils were found to closely resemble the T1 relaxation times and imaging characteristics of these two tissues, which are 1,515.8±105.5 and 405.4±15.1 ms, respectively. The agarose gel with different concentrations, ranging from 0.5 to 2.5 wt%, was found to have the longest T1 relaxation times.

Conclusions

A patient-specific 3D-printed breast phantom was successfully designed and constructed using silicone and peanut oils to simulate the MR imaging characteristics of fibroglandular and adipose tissues. The phantom can be used to investigate different MR breast imaging protocols for the quantitative assessment of breast density.

Preparation and In Vitro Evaluation of Neutron-Activated, Theranostic Samarium-153-Labeled Microspheres for Transarterial Radioembolization of Hepatocellular Carcinoma and Liver Metastasis

Introduction: Transarterial radioembolization (TARE) has been proven as an effective treatment for unresectable liver tumor. In this study, neutron activated, ¹⁵³Sm-labeled microspheres were developed as an alternative to ⁹⁰Y-labeled microspheres for hepatic radioembolization. ¹⁵³Sm has a theranostic advantage as it emits both therapeutic beta and diagnostic gamma radiations simultaneously, in comparison to the pure beta emitter, ⁹⁰Y. Methods: Negatively charged acrylic microspheres were labeled with ¹⁵²Sm ions through electrostatic interactions. In another formulation, the Sm-labeled microsphere was treated with sodium carbonate solution to form the insoluble ¹⁵²Sm carbonate (¹⁵²SmC) salt within the porous structures of the microspheres. Both formulations were neutron-activated in a research reactor. Physicochemical characterization, gamma spectrometry, and radiolabel stability tests were carried out to study the performance and stability of the microspheres. Results: The Sm- and SmC-labeled microspheres remained spherical and smooth, with a mean size of 35 µm before and after neutron activation. Fourier transform infrared (FTIR) spectroscopy indicated that the functional groups of the microspheres remained unaffected after neutron activation. The ¹⁵³Sm- and ¹⁵³SmC-labeled microspheres achieved activity of 2.53 ± 0.08 and 2.40 ± 0.13 GBq·g⁻¹, respectively, immediate after 6 h neutron activation in the neutron flux of 2.0 × 10¹² n·cm⁻²·s⁻¹. Energy-dispersive X-ray (EDX) and gamma spectrometry showed that no elemental and radioactive impurities were present in the microspheres after neutron activation. The retention efficiency of ¹⁵³Sm in the ¹⁵³SmC-labeled microspheres was excellent (~99% in distilled water and saline; ~97% in human blood plasma), which was higher than the ¹⁵³Sm-labeled microspheres (~95% and ~85%, respectively). Conclusion: ¹⁵³SmC-labeled microspheres have demonstrated excellent properties for potential application as theranostic agents for hepatic radioembolization.

Personalized administration of contrast medium with high delivery rate in low tube voltage coronary computed tomography angiography

Background

High delivery rate is an important factor in optimizing contrast medium administration in coronary computed tomography angiography (CCTA). A personalized contrast volume calculation algorithm incorporating high iodine delivery rate (IDR) can reduce total iodine dose (TID) and produce optimal vessel contrast enhancement (VCE) in low tube voltage CCTA. In this study, we developed and validated an algorithm for calculating the volume of contrast medium delivered at a high rate for patients undergoing retrospectively ECG-gated CCTA with low tube voltage protocol.

Methods

The algorithm for an IDR of 2.22 gI·s^-1 was developed based on the relationship between VCE and contrast volume in 141 patients; test bolus parameters and characteristics in 75 patients; and, tube voltage in a phantom study. The algorithm was retrospectively tested in 45 patients who underwent retrospectively ECG-gated CCTA with a 100 kVp protocol. Image quality, TID and radiation dose exposure were compared with those produced using the 120 kVp and routine contrast protocols.

Results

Age, sex, body surface area (BSA) and peak contrast enhancement (PCE) were significant predictors for VCE (P<0.05). A strong linear correlation was observed between VCE and contrast volume (r=0.97, P<0.05). The 100-to-120 kVp contrast enhancement conversion factor (E_c) was calculated at 0.81. Optimal VCE (250 to 450 HU) and diagnostic image quality were obtained with significant reductions in TID (32.1%) and radiation dose (38.5%) when using 100 kVp and personalized contrast volume calculation algorithm compared with 120 kVp and routine contrast protocols (P<0.05).

Conclusions

The proposed algorithm could significantly reduce TID and radiation exposure while maintaining optimal VCE and image quality in CCTA with 100 kVp protocol.

Quantitative and qualitative comparison of low- and high-cost 3D-printed heart models

Current visualization techniques of complex congenital heart disease (CHD) are unable to provide comprehensive visualization of the anomalous cardiac anatomy as the medical datasets can essentially only be viewed from a flat, two-dimensional (2D) screen. Three-dimensional (3D) printing has therefore been used to replicate patient-specific hearts in 3D views based on medical imaging datasets. This technique has been shown to have a positive impact on the preoperative planning of corrective surgery, patient-doctor communication, and the learning experience of medical students. However, 3D printing is often costly, and this impedes the routine application of this technology in clinical practice. This technical note aims to investigate whether reducing 3D printing costs can have any impact on the clinical value of the 3D-printed heart models. Low-cost and a high-cost 3D-printed models based on a selected case of CHD were generated with materials of differing cost. Quantitative assessment of dimensional accuracy of the cardiac anatomy and pathology was compared between the 3D-printed models and the original cardiac computed tomography (CT) images with excellent correlation (r=0.99). Qualitative evaluation of model usefulness showed no difference between the two models in medical applications.

Patient-specific 3D printed model of biliary ducts with congenital cyst

BACKGROUND

3D printing has shown great promise in medical applications, with increasing reports in liver diseases. However, research on 3D printing in biliary disease is limited with lack of studies on validation of model accuracy. In this study, we presented our experience of creating a realistic 3D printed model of biliary ducts with congenital cyst. Measurements of anatomical landmarks were compared at different stages of model generation to determine dimensional accuracy.

METHODS

Contrast-enhanced computed tomography (CT) images of a patient diagnosed with congenital cyst in the common bile duct with dilated hepatic ducts were used to create the 3D printed model. The 3D printed model was scanned on a 64-slice CT scanner using the similar abdominal CT protocol. Measurements of anatomical structures including common hepatic duct (CHD), right hepatic duct (RHD), left hepatic duct (LHD) and the cyst at left to right and anterior to posterior dimensions were performed and compared between original CT images, the standard tessellation language (STL) image and CT images of the 3D model.

RESULTS

The 3D printing model was successfully generated with replication of biliary ducts and cyst. Significant differences in measurements of these landmarks were found between the STL and the original CT images, and the CT images of the 3D printed model and the original CT images (P<0.05). Measurements of the RHD and LHD diameters from the original CT images were significantly larger than those from the CT images of 3D model or STL file (P<0.05), while measurements of the CHD diameters were significantly smaller than those of the other two datasets (P<0.05). No significant differences were reached in measurements of the CHD, RHD, LHD and the biliary cyst between CT images of the 3D printed model and STL file (P=0.08-0.98).

CONCLUSIONS

This study shows our experience in producing a realistic 3D printed model of biliary ducts and biliary cyst. The model was found to replicate anatomical structures and cyst with high accuracy between the STL file and the CT images of the 3D model. Large discrepancy in dimensional measurements was noted between the original CT and STL file images, and the original CT and CT images of the 3D model, highlighting the necessity of further research with inclusion of more cases of biliary disease to validate accuracy of 3D printed biliary models.

Polyethylene glycol-coated porous magnetic nanoparticles for targeted delivery of chemotherapeutics under magnetic hyperthermia condition

PURPOSE

Although magnetite nanoparticles (MNPs) are promising agents for hyperthermia therapy, insufficient drug encapsulation efficacies inhibit their application as nanocarriers in the targeted drug delivery systems. In this study, porous magnetite nanoparticles (PMNPs) were synthesized and coated with a thermosensitive polymeric shell to obtain a synergistic effect of hyperthermia and chemotherapy.

MATERIALS AND METHODS

PMNPs were produced using cetyltrimethyl ammonium bromide template and then coated by a polyethylene glycol layer with molecular weight of 1500 Da (PEG1500) and phase transition temperature of 48 ± 2 °C to endow a thermosensitive behavior. The profile of drug release from the nanostructure was studied at various hyperthermia conditions generated by waterbath, magnetic resonance-guided focused ultrasound (MRgFUS), and alternating magnetic field (AMF). The in vitro cytotoxicity and hyperthermia efficacy of the doxorubicin-loaded nanoparticles (DOX-PEG1500-PMNPs) were assessed using human lung adenocarcinoma (A549) cells.

RESULTS

Heat treatment of DOX-PEG1500-PMNPs containing 235 ± 26 mg·g^-1 DOX at 48 °C by waterbath, MRgFUS, and AMF, respectively led to 71 ± 4%, 48 ± 3%, and 74 ± 5% drug release. Hyperthermia treatment of the A549 cells using DOX-PEG1500-PMNPs led to 77% decrease in the cell viability due to the synergistic effects of magnetic hyperthermia and chemotherapy.

CONCLUSION

The large pores generated in the PMNPs structure could provide a sufficient space for encapsulation of the chemotherapeutics as well as fast drug encapsulation and release kinetics, which together with thermosensitive characteristics of the PEG1500 shell, make DOX-PEG1500-PMNPs promising adjuvants to the magnetic hyperthermia modality.

Automated detection and classification of liver fibrosis stages using contourlet transform and nonlinear features

BACKGROUND AND OBJECTIVE

Liver fibrosis is a type of chronic liver injury that is characterized by an excessive deposition of extracellular matrix protein. Early detection of liver fibrosis may prevent further growth toward liver cirrhosis and hepatocellular carcinoma. In the past, the only method to assess liver fibrosis was through biopsy, but this examination is invasive, expensive, prone to sampling errors, and may cause complications such as bleeding. Ultrasound-based elastography is a promising tool to measure tissue elasticity in real time; however, this technology requires an upgrade of the ultrasound system and software. In this study, a novel computer-aided diagnosis tool is proposed to automatically detect and classify the various stages of liver fibrosis based upon conventional B-mode ultrasound images.

METHODS

The proposed method uses a 2D contourlet transform and a set of texture features that are efficiently extracted from the transformed image. Then, the combination of a kernel discriminant analysis (KDA)-based feature reduction technique and analysis of variance (ANOVA)-based feature ranking technique was used, and the images were then classified into various stages of liver fibrosis.

RESULTS

Our 2D contourlet transform and texture feature analysis approach achieved a 91.46% accuracy using only four features input to the probabilistic neural network classifier, to classify the five stages of liver fibrosis. It also achieved a 92.16% sensitivity and 88.92% specificity for the same model. The evaluation was done on a database of 762 ultrasound images belonging to five different stages of liver fibrosis.

CONCLUSIONS

The findings suggest that the proposed method can be useful to automatically detect and classify liver fibrosis, which would greatly assist clinicians in making an accurate diagnosis.

Low tube voltage prospectively ECG-triggered coronary CT angiography: a systematic review of image quality and radiation dose

OBJECTIVE

This study aimed (1) to perform a systematic review on scanning parameters and contrast medium (CM) reduction methods used in prospectively electrocardiography (ECG-triggered low tube voltage coronary CT angiography (CCTA), (2) to compare the achievable dose reduction and image quality and (3) to propose appropriate scanning techniques and CM administration methods.

METHODS

A systematic search was performed in PubMed, the Cochrane library, CINAHL, Web of Science, ScienceDirect and Scopus, where 20 studies were selected for analysis of scanning parameters and CM reduction methods.

RESULTS

The mean effective dose (H_E) ranged from 0.31 to 2.75 mSv at 80 kVp, 0.69 to 6.29 mSv at 100 kVp and 1.53 to 10.7 mSv at 120 kVp. Radiation dose reductions of 38 to 83% at 80 kVp and 3 to 80% at 100 kVp could be achieved with preserved image quality. Similar vessel contrast enhancement to 120 kVp could be obtained by applying iodine delivery rate (IDR) of 1.35 to 1.45 g s^-1 with total iodine dose (TID) of between 10.9 and 16.2 g at 80 kVp and IDR of 1.08 to 1.70 g s^-1 with TID of between 18.9 and 20.9 g at 100 kVp.

CONCLUSION

This systematic review found that radiation doses could be reduced to a rate of 38 to 83% at 80 kVp, and 3 to 80% at 100 kVp without compromising the image quality. Advances in knowledge: The suggested appropriate scanning parameters and CM reduction methods can be used to help users in achieving diagnostic image quality with reduced radiation dose.

Optimized multi-level elongated quinary patterns for the assessment of thyroid nodules in ultrasound images

Ultrasound imaging is one of the most common visualizing tools used by radiologists to identify the location of thyroid nodules. However, visual assessment of nodules is difficult and often affected by inter- and intra-observer variabilities. Thus, a computer-aided diagnosis (CAD) system can be helpful to cross-verify the severity of nodules. This paper proposes a new CAD system to characterize thyroid nodules using optimized multi-level elongated quinary patterns. In this study, higher order spectral (HOS) entropy features extracted from these patterns appropriately distinguished benign and malignant nodules under particle swarm optimization (PSO) and support vector machine (SVM) frameworks. Our CAD algorithm achieved a maximum accuracy of 97.71% and 97.01% in private and public datasets respectively. The evaluation of this CAD system on both private and public datasets confirmed its effectiveness as a secondary tool in assisting radiological findings.

Elasticity Characterization of Liver Cancers Using Shear Wave Ultrasound Elastography: Comparison Between Hepatocellular Carcinoma and Liver Metastasis

Purpose:

This was a feasibility study of shear wave ultrasound elastography for characterization of liver tumors and to compare the tissue elasticity values of hepatocellular carcinoma (HCC), liver metastases, and normal liver tissues.

Methods:

Forty-one patients and 30 healthy volunteers were recruited and categorized into HCC, liver metastasis, and control groups based on their computed tomography and sonographic examinations. Elasticity values of different groups were compared statistically.

Results:

Mean (standard deviation) elasticity values for HCC, liver metastasis, and normal liver tissue were 51.45 (14.96), 49.89 (13.82), and 6.63 (1.65) kilopascal, respectively. Statistically significant differences were found between the elasticity values of HCC and liver metastasis with normal liver tissue. Based on the receiver operating characteristics analysis, 18.25 kilopascal may differentiate the malignant focal liver lesions from the normal liver tissue with both sensitivity and specificity of 100%.

Conclusion:

Shear wave ultrasound elastography may be able to differentiate HCC and liver metastasis from normal liver tissue based on the tissue elasticity values.

Critical Parameters for Particle-Based Pulmonary Delivery of Chemotherapeutics

Targeted delivery of chemotherapeutics through the respiratory system is a potential approach to improve drug accumulation in the lung tumor, while decreasing their negative side effects. However, elimination by the pulmonary clearance mechanisms, including the mucociliary transport system, and ingestion by the alveolar macrophages, rapid absorption into the blood, enzymatic degradation, and low control over the deposition rate and location remain the main complications for achieving an effective pulmonary drug delivery. Therefore, particle-based delivery systems have emerged to minimize pulmonary clearance mechanisms, enhance drug therapeutic efficacy, and control the release behavior. A successful implementation of a particle-based delivery system requires understanding the influential parameters in terms of drug carrier, inhalation technology, and health status of the patient's respiratory system. This review aims at investigating the parameters that significantly drive the clinical outcomes of various particle-based pulmonary delivery systems. This should aid clinicians in appropriate selection of a delivery system according to their clinical setting. It will also guide researchers in addressing the remaining challenges that need to be overcome to enhance the efficiency of current pulmonary delivery systems for aerosols.

Gastroretentive behavior of orally administered radiolabeled tamarind seed formulations in rabbits validated by gamma scintigraphy

This study aimed to formulate floating gastroretentive tablets containing metformin hydrochloric acid (HCl), using various grades of hydrogel such as tamarind powders and xanthan to overcome short gastric residence time of the conventional dosage forms. Different concentrations of the hydrogels were tested to determine the formulation that could provide a sustained release of 12 h. Eleven formulations with different ratios of tamarind seed powder/tamarind kernel powder (TKP):xanthan were prepared. The physical parameters were observed, and in vitro drug-release studies of the prepared formulations were carried out. Optimal formulation was assessed for physicochemical properties, thermal stability, and chemical interaction followed by in vivo gamma scintigraphy study. MKP3 formulation with a TKP:xanthan ratio of 3:2 was found to have 99.87% release over 12 h. Furthermore, in vivo gamma scintigraphy study was carried out for the optimized formulation in healthy New Zealand White rabbits, and the pharmacokinetic parameters of developed formulations were obtained. 153Sm2O3 was used to trace the profile of release in the gastrointestinal tract of the rabbits, and the drug release was analyzed. The time (Tmax) at which the maximum concentration of metformin HCl in the blood (Cmax) was observed, and it was extended four times for the gastroretentive formulation in comparison with the formulation without polymers. Cmax and the half-life were found to be within an acceptable range. It is therefore concluded that MKP3 is the optimal formulation for sustained release of metformin HCl over a period of 12 h as a result of its floating properties in the gastric region.

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols

OBJECTIVES

This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE).

MATERIALS AND METHODS

Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region.

RESULTS

Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor.

CONCLUSION

The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners.

Gamma scintigraphic evaluation of floating gastroretentive tablets of metformin HCl using a combination of three natural polymers in rabbits

The present research was aimed at formulating a metformin HCl sustained-release formulation from a combination of polymers, using the wet granulation technique. A total of 16 formulations (F1–F16) were produced using different combinations of the gel-forming polymers: tamarind kernel powder, salep (palmate tubers of Orchis morio), and xanthan. Post-compression studies showed that there were no interactions between the active drug and the polymers. Results of in vitro drug-release studies indicated that the F10 formulation which contained 5 mg of tamarind kernel powder, 33.33 mg of xanthan, and 61.67 mg of salep could sustain a 95% release in 12 hours. The results also showed that F2 had a 55% similarity factor with the commercial formulation (C-ER), and the release kinetics were explained with zero order and Higuchi models. The in vivo study was performed in New Zealand White rabbits by gamma scintigraphy; the F10 formulation was radiolabeled using samarium (III) oxide (¹⁵³Sm₂O₃) to trace transit of the tablets in the gastrointestinal tract. The in vivo data supported the retention of F10 formulation in the gastric region for 12 hours. In conclusion, the use of a combination of polymers in this study helped to develop an optimal gastroretentive drug-delivery system with improved bioavailability, swelling, and floating characteristics.

Gamma scintigraphic study of the hydrodynamically balanced matrix tablets of Metformin HCl in rabbits

The purpose of this study is to evaluate the in vitro and in vivo performance of gastro-retentive matrix tablets having Metformin HCl as model drug and combination of natural polymers. A total of 16 formulations were prepared by a wet granulation method using xanthan, tamarind seed powder, tamarind kernel powder and salep as the gel-forming agents and sodium bicarbonate as a gas-forming agent. All the formulations were evaluated for compendial and non-compendial tests and in vitro study was carried out on a USP-II dissolution apparatus at a paddle speed of 50 rpm. MOX2 formulation, composed of salep and xanthan in the ratio of 4:1 with 96.9% release, was considered as the optimum formulation with more than 90% release in 12 hours and short floating lag time. In vivo study was carried out using gamma scintigraphy in New Zealand White rabbits, optimized formulation was incorporated with 10 mg of ¹⁵³Sm for labeling MOX2 formulation. The radioactive samarium oxide was used as the marker to trace transit of the tablets in the gastrointestinal tract. The in vivo data also supported retention of MOX2 formulation in the gastric region for 12 hours and were different from the control formulation without a gas and gel forming agent. It was concluded that the prepared floating gastro-retentive matrix tablets had a sustained-release effect in vitro and in vivo, gamma scintigraphy played an important role in locating the oral transit and the drug-release pattern.

Robotic-assisted thermal ablation of liver tumours

OBJECTIVE

This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system.

METHODS

Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance.

RESULTS

Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method.

CONCLUSION

This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients.

KEY POINTS

• Clinical experience on liver thermal ablation using CT-guided robotic system is reported. • The technical success, radiation dose, safety and performance level were assessed. • Thermal ablations were successfully performed, with an average performance score of 4.4/5.0. • Robotic-assisted ablation can potentially increase capabilities of less skilled interventional radiologists. • Cost-effectiveness needs to be proven in further studies.