Enhancing Tissue Equivalence in 7Li Heavy Ion Therapy with MC Algorithm Optimized Polymer-Based Bioinks

The unique physical properties of heavy ion beams, particularly their distinctive depth-dose distribution and sharp lateral dose reduction profiles, have led to their widespread adoption in tumor therapy worldwide. However, the physical properties of heavy ion beams must be investigated to deliver a sufficient dose to tumors without damaging organs at risk. These studies should be performed on phantoms made of biomaterials that closely mimic human tissue. Polymers can serve as soft tissue substitutes and are suitable materials for building radiological phantoms due to their physical, mechanical, biological, and chemical properties. Extensive research, development, and applications of polymeric biomaterials have been encouraged due to these properties. In this study, we investigated the ionization, recoils, phonon release, collision events, and lateral straggle properties of polymeric biomaterials that closely resemble soft tissue using lithium-ion beams and Monte Carlo Transport of Ions in Matter simulation. The results indicated that the Bragg peak position closest to soft tissue was achieved with a 7.3% difference in polymethylmethacrylate, with an average recoils value of 10.5%. Additionally, average values of 33% were observed in collision events and 22.6% in lateral straggle. A significant contribution of this study to the existing literature lies in the exploration of secondary interactions alongside the assessment of linear energy transfer induced by the 7Li beam used for treatment. Furthermore, we analyzed the tissue-equivalent properties of polymer biomaterials using heavy ion beams, taking into account phonon release resulting from ionization, recoils, lateral straggle, and all other interactions. This approach allows for the evaluation of the most suitable polymeric biomaterials for heavy ion therapy while considering the full range of interactions involved.

MC TRIM Algorithm in Mandibula Phantom in Helium Therapy

Helium ion beam therapy, one of the particle therapies developed and studied in the 1950s for cancer treatment, resulted in clinical trials starting at Lawrence Berkeley National Laboratory in 1975. While proton and carbon ion therapies have been implemented in research institutions and hospitals globally after the end of the trials, progress in comprehending the physical, biological, and clinical findings of helium ion beam therapy has been limited, particularly due to its limited accessibility. Ongoing efforts aim to establish programs that evaluate the use of helium ion beams for clinical and research purposes, especially in the treatment of sensitive clinical cases. Additionally, helium ions have superior physical properties to proton beams, such as lower lateral scattering and larger LET. Moreover, they exhibit similar physical characteristics to carbon, oxygen, and neon ions, which are all used in heavy ion therapy. However, they demonstrate a sharper lateral penumbra with a lower radiobiological absence of certainties and lack the degradation of variations in dose distributions caused by excessive fragmenting of heavier-ion beams, especially at greater depths of penetration. In this context, the status and the prospective advancements of helium ion therapy are examined by investigating ionization, recoil, and lateral scattering values using MC TRIM algorithms in mandible plate phantoms designed from both tissue and previously studied biomaterials, providing an overview for dental cancer treatment. An average difference of 1.9% in the Bragg peak positions and 0.211 mm in lateral scattering was observed in both phantoms. Therefore, it is suggested that the 4He ion beam can be used in the treatment of mandibular tumors, and experimental research is recommended using the proposed biomaterial mandible plate phantom.

Monte Carlo Simulation of TRIM Algorithm in Ceramic Biomaterial in Proton Therapy

Biomaterials play a crucial role in enhancing human health and quality of life. They are employed in applications such as tissue substitution, diagnostic tools, medical supplies, therapeutic treatments, regenerative medicine, and radiation dosimetric studies. However, their predisposition to proton therapy, which is a trending treatment in the world, has not been adequately studied. Ceramic biomaterials, known for their hardness and durability, offer versatile uses, especially in bone tissue replacements. The wide range of physical, mechanical, and chemical properties exhibited by ceramics has spurred extensive research, development, and application in this field. This study focuses on investigating and analyzing the ionization, recoils, phonon release, collision events, and lateral scattering properties of ceramic biomaterials that closely resemble bone tissue in proton therapy applications. Monte Carlo (MC) Transport of Ions in Matter (TRIM) simulation tools were utilized for this analysis. The results showed that Silicon dioxide exhibited the Bragg peak position closest to bone tissue, with a deviation of 10.6%. The average recoils differed by 1.7%, and the lateral scattering differed by 3.6%. The main innovation of this study lies in considering interactions such as recoil, collision events, phonon production, and lateral scattering when selecting biomaterials, despite their limited digitization and understanding. By evaluating all these interactions, the study aimed to identify the most suitable ceramic biomaterial to replace bone tissue in proton therapy.

Performance and analysis of four pediatric mortality prediction scores among critically ill children: A multicenter prospective observational study in four PICUs

OBJECTIVE

We aimed to evaluate and compare the prognostic performance of common pediatric mortality scoring systems (the Pediatric Index of Mortality 2 [PIM2], PIM3, Pediatric Risk of Mortality [PRISM], and PRISM4 scores) to determine which is the most applicable score in our pediatric study cohort.

METHODS

This prospective observational multicenter cohort study was conducted in four tertiary-care pediatric intensive care units (PICUs) in Turkey. All children, between 1 month and 16 years old, admitted to the participating PICUs between October 1, 2019, and March 31, 2020, were included in the study. Discrimination between death and survival was assessed by area under the receiver operating characteristic plot (AUC) for each model. The Hosmer-Lemeshow goodness-of-fit (GOF) test was used to assess the calibration of the models, RESULTS: A total of 570 patients (median age 35 months) were enrolled in the study. The observed mortality rate was 8.2% (47/570). The standardized mortality ratio (SMR) of PIM2, PIM3, PRISM, and PRISM4 with 95% confidence interval (CI) were 0.94 (0.68-1.23), 1.27 (0.93-1.68), 0.86 (0.63-1.13), and 1.5 (1.10-1.97), respectively. The AUC with 95% CI was 0.934 (0.91-0.96) for PIM2, 0.934 (0.91-0.96) for PIM3, 0.917 (0.88-0.95) for PRISM, and 0.926 (0.88-0.97) for PRISM4 models. The Hosmer-Lemeshow test showed that the difference between observed and predicted mortality by PIM3 (p = 0.003) and PRISM4 (p = 0.008) was statistically significant whereas PIM2 (p = 0.28) and PRISM (p = 0.62) showed good calibration.

CONCLUSION

The overall performance of (both discrimination and calibration) PRISM and PIM2 scoring systems in Turkish pediatric patients aged 1 month to 16 years was accurate and had the best fit for risk groups according to our study. Although PIM3 and PRISM4 have good discriminatory power, their calibration was very poor in our study cohort.

A rare complication of pica: Stone aspiration with severe respiratory distress

Tracheobronchial foreign body aspiration (FBA), a common pediatric presentation to emergency departments, is still a public healthcare problem affecting children all over the world. There are several types of foreign bodies reported from different parts of the world, including both organic or nonorganic substances. Pica, another interesting clinical entity, is characterized by persistent eating of nonnutritive substances, which is inappropriate for the maturation stage of the individual. A 3-year-old pediatric patient was admitted to our emergency department with a 3-day history of coughing and new onset respiratory distress. A chest X-ray was performed and it showed a suspicious radiopaque foreign body in the localization of left bronchi. Urgent rigid bronchoscopy was performed. The foreign body in the left main bronchi was, surprisingly, a 0.5-1 cm diameter, irregularly shaped stone particle. The laboratory evaluations and patient history revealed the diagnosis of severe iron deficiency anemia and accompanying pica. Stone aspiration, as an FBA, is a rare but potentially life-threatening complication of pica. Iron deficiency anemia accompanied by pica should be diagnosed and treated in the early stage of the disease because of their complications. According to our knowledge and literature search, this is the first case of stone aspiration as a complication of severe iron deficiency anemia and pica.

Proton Therapy for Mandibula Plate Phantom

Purpose: In this study, the required dose rates for optimal treatment of tumoral tissues when using proton therapy in the treatment of defective tumours seen in mandibles has been calculated. We aimed to protect the surrounding soft and hard tissues from unnecessary radiation as well as to prevent complications of radiation. Bragg curves of therapeutic energized protons for two different mandible (molar and premolar) plate phantoms were computed and compared with similar calculations in the literature. The results were found to be within acceptable deviation values. Methods: In this study, mandibular tooth plate phantoms were modelled for the molar and premolar areas and then a Monte Carlo simulation was used to calculate the Bragg curve, lateral straggle/range and recoil values of protons remaining in the therapeutic energy ranges. The mass and atomic densities of all the jawbone layers were selected and the effect of layer type and thickness on the Bragg curve, lateral straggle/range and the recoil were investigated. As protons move through different layers of density, lateral straggle and increases in the range were observed. A range of energies was used for the treatment of tumours at different depths in the mandible phantom. Results: Simulations revealed that as the cortical bone thickness increased, Bragg peak position decreased between 0.47–3.3%. An increase in the number of layers results in a decrease in the Bragg peak position. Finally, as the proton energy increased, the amplitude of the second peak and its effect on Bragg peak position decreased. Conclusion: These findings should guide the selection of appropriate energy levels in the treatment of tumour structures without damaging surrounding tissues.

Metastatic Pancreatic Cancer Second-Line Treatment Options: Is the Difference Only in Cost?

İNTRODUCTION: Although pancreatic cancer ranks seventh in cancer-related deaths, it is an extremely fatal disease, and more than 330,000 people die from this disease worldwide. Although there are many first-line treatment studies in the literature, there are almost no prospective studies regarding second-line therapy. Therefore, there is no standard approach in the second-line treatment of pancreatic cancer. We decided to conduct this study to investigate second-line treatments with problems such as cost, treatment efficacy, and toxicity.

METHODS

Patients older than 18 years old who applied to Ege University Hospital medical oncology department with a diagnosis of metastatic pancreatic cancer, who received first-line chemotherapy due to their illness, and who had progressed afterwards were included in the study. The files of the patients who applied between 2013 and 2017 were examined.

RESULTS

Our study's primary endpoint was progression-free survival, and it was found that the median progression-free survival was 3.2 months in the Xelox patients, 3.7 months in the gemcitabine-nab paclitaxel patients, and 3.5 months in the other regimens. When the secondary endpoint was evaluated, overall survival, the median overall survival was 5.9 months in the Xelox patients, 5.3 months in the gemcitabine-nab paclitaxel patients, and 4.8 months in the other regimens.

CONCLUSION

As a result, second-line treatments were compared, and no statistically significant difference was found between them. For this reason, the side effects of previously used drugs and the side effects of new drugs to be used, as well as their costs, should be evaluated when choosing a treatment.

JAK2 V617F MUTATION SCANNING IN PATIENTS WITH ADRENAL INCIDENTALOMA

OBJECTIVE

Adrenal incidentaloma are lesions which are stated incidentally by imaging methods when there is no suspicion of any disease in adrenal gland. Inappropriate Jak2 signaling causes some solid and hematological malignancies. But the Jak2 mutation has not been previously evaluated with regard to adrenal tumors. In this study, we aimed to positivity of the Jak2 mutation in patients with non functioning adrenal incidentaloma (NFAI).

METHODS

45 (38 female-7 male) patients, who were followed due to NFAI at Tepecik Training and Research Hospital, Department of Endocrinology and Internal Medicine between February 2014 and March 2015, and 45 (31 female-14 male) healthy controls were included in the study.

RESULTS

The average age was 54.02±11.7 years and 38 patients were female, 7 were men. All patients underwent the following analyses for excluding a functioning adrenal mass, overnight dexamethasone suppression test, 24 hour urinary metanephrine and normetanephrine, plasma aldosterone/ renin activity ratio. Jak2 mutation of the patients who were diagnosed as NFAI was all negative.

CONCLUSION

We could not identify the JAK2 gene mutation positivity in any sample. Since other possible mechanisms may throw fresh light on the etiology of adrenal incidentaloma, further clinical studies are needed on this subject.