Lung Segmentation using Active Shape Model to Detect the Disease from Chest Radiography.

BACKGROUND: Some parametric models are used to diagnose problems of lung segmentation more easily and effectively. OBJECTIVE: The present study aims to detect lung diseases (nodules and tuberculosis) better using an active shape model (ASM) from chest radiographs. MATERIAL AND METHODS: In this analytical study, six grouping methods, including three primary methods such as physicians, Dice similarity, and correlation coefficients) and also three secondary methods using SVM (Support Vector Machine) were used to classify the chest radiographs regarding diaphragm congestion and heart reshaping. The most effective method, based on the evaluation of the results by a radiologist, was found and used as input data for segmenting the images by active shape model (ASM). Several segmentation parameters were evaluated to calculate the accuracy of segmentation. This work was conducted on JSRT (Japanese Society of Radiological Technology) database images and tuberculosis database images were used for validation. RESULTS: The results indicated that the ASM can detect 94.12 ± 2.34 % and 94.38 ± 3.74 % (mean± standard deviation) of pulmonary nodules in left and right lungs, respectively, from the JRST radiology datasets. Furthermore, the ASM model detected 88.33 ± 6.72 % and 90.37 ± 5.48 % of tuberculosis in left and right lungs, respectively. CONCLUSION: The ASM segmentation method combined with pre-segmentation grouping can be used as a preliminary step to identify areas with tuberculosis or pulmonary nodules. In addition, this presented approach can be used to measure the size and dimensions of the heart in future studies.

Skin dose measurement and estimating the dosimetric effect of applicator misplacement in gynecological brachytherapy: A patient and phantom study.

OBJECTIVES: To evaluate skin dose differences between TPS (treatment planning system) calculations and TLD (thermo-luminescent dosimeters) measurements along with the dosimetric effect of applicator misplacement for patients diagnosed with gynecological (GYN) cancers undergoing brachytherapy. METHODS: The skin doses were measured using TLDs attached in different locations on patients' skin in pelvic regions (anterior, left, and right) for 20 patients, as well as on a phantom. In addition, the applicator surface dose was calculated with TLDs attached to the applicator. The measured doses were compared with TPS calculations to find TPS accuracy. For the phantom, different applicator shifts were applied to find the effect of applicator misplacement on the surface dose. RESULTS: The mean absolute dose differences between the TPS and TLDs results for anterior, left, and right points were 3.14±1.03, 6.25±1.88, and 6.20±1.97 %, respectively. The mean difference on the applicator surface was obtained 1.92±0.46 %. Applicator misplacements of 0.5, 2, and 4 cm (average of three locations) resulted in 9, 36, and 61%, dose errors respectively. CONCLUSIONS: The surface/skin differences between the calculations and measurements are higher in the left and right regions, which relate to the higher uncertainty of TPS dose calculation in these regions. Furthermore, applicator misplacements can result in high skin dose variations, therefore it can be an appropriate quality assurance method for future research.

The role of melatonin on radiation-induced pneumonitis and lung fibrosis: A systematic review.

PURPOSE: Pneumonitis and lung fibrosis, as the most common compliances of lung irradiation, can affect the quality of life. The use of radio-protective agents can ameliorate these injuries. This study aimed to review the potential protective role of melatonin in the treatment of radiation-induced Pneumonitis and lung fibrosis. METHODS: The current systematic study was conducted based on PRISMA guidelines to identify relevant literature on " the effect of melatonin on radiation-induced pneumonitis and lung fibrosis" in the electronic databases of Web of Science, Embase, PubMed, and Scopus up to January 2021. Eighty-one articles were screened in accordance with the inclusion and exclusion criteria of the study. Finally, eight articles were included in this systematic review. RESULTS: The finding showed that the lung irradiation-induced pneumonitis and lung fibrosis. The co-treatment with melatonin could alleviate these compliances through its anti-oxidant and anti-inflammatory actions. Melatonin through upregulation of some enzymes such as catalase, superoxide dismutase, glutathione, NADPH oxidases 2 and 4, dual oxidases 1 and 2, and also downregulation of malondialdehyde reduced oxidative stress following lung radiation. Moreover, melatonin through its anti-inflammatory effects, can attenuate the increased levels of nuclear factor kappa B, tumor necrosis factor alpha, transforming growth factor beta 1, SMAD2, interleukin (IL)-4, IL-4 receptor-a1 (IL4ra1), and IL-1 beta following lung radiation. The histological damages induced by ionizing radiation were also alleviated by co-treatment with melatonin. CONCLUSION: According to the obtained results, it was found that melatonin can have anti-pneumonitis and anti-fibrotic following lung irradiation.

The radioprotective effects of alpha-lipoic acid on radiotherapy-induced toxicities: A systematic review.

PURPOSE: Radiation therapy is one of the main cancer treatment modalities applied in 50-70% of cancer patients. Despite the many advantages of this treatment, such as non-invasiveness, organ-preservation, and spatiotemporal flexibility in tumor targeting, it can lead to complications in irradiated healthy cells/tissues. In this regard, the use of radio-protective agents can alleviate radiation-induced complications. This study aimed to review the potential role of alpha-lipoic acid in the prevention/reduction of radiation-induced toxicities on healthy cells/tissues. METHODS: A systematic search was performed following PRISMA guidelines to identify relevant literature on the "role of alpha-lipoic acid in the treatment of radiotherapy-induced toxicity" in the electronic databases of Web of Science, Embase, PubMed, and Scopus up to January 2021. Based on the inclusion and exclusion criteria of the present study, 278 articles were screened. Finally, 29 articles were included in this systematic review. RESULTS: The obtained results showed that in experimental in vivo models, the radiation-treated groups had decreased survival rate and body weight compared to the control groups. It was also found that radiation can induce mild to severe toxicities on gastrointestinal, circulatory, reproductive, central nervous, respiratory, endocrine, exocrine systems, etc. However, the use of alpha-lipoic acid could alleviate the radiation-induced toxicities in most cases. This radio-protective agent exerts its effects through mechanisms of anti-oxidant, anti-apoptosis, anti-inflammatory, and so on. CONCLUSION: According to the obtained results, it can be mentioned that co-treatment of alpha-lipoic acid with radiotherapy ameliorates the radiation-induced toxicities in healthy cells/tissues.

The Measurement of Thyroid Absorbed dose by Gafchromic™ EBT2 Film and Changes in Thyroid Hormone Levels Following Radiotherapy in Patients with Breast Cancer.

BACKGROUND: Radiotherapy is a main method for the treatment of breast cancer. This study aimed to measure the absorbed dose of thyroid gland using Gafchromic EBT2 film during breast cancer radiotherapy. In addition, the relationship between the absorbed dose and thyroid hormone levels was evaluated. METHODS: Forty-six breast cancer patients, with the age ranged between 25 and 35 years, undergoing external radiotherapy were studied. The patients were treated with 6 and 18 MV X-ray beams, and the absorbed thyroid dose was measured by EBT2 film. Thyroid hormone levels, thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxin (T4), were measured before and after the radiotherapy. Pearson's, Spearman's, and Chi-square tests were performed to evaluate the correlation between the thyroid dose and hormone levels. RESULTS: The mean thyroid dose was 26 ± 9.45 cGy with the range of 7.85-48.35 cGy. There were not any significant differences at thyroid hormone levels between preradiotherapy and postradiotherapy (P > 0.05). There was a significant relationship between increased thyroid absorbed dose and changes in TSH and T4 levels (P < 0.05), but it was not significant in T3 level (P = 0.1). CONCLUSION: Regarding the results, the thyroid absorbed dose can have an effect on its function. Therefore, the thyroid gland should be considered as an organ at risk in breast cancer radiotherapy.

Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

OBJECTIVES: Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. METHODS: Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. RESULTS: An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. CONCLUSION: Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.