A Cascade Transformer-based Model for 3D Dose Distribution Prediction in Head and Neck Cancer Radiotherapy

Radiation therapy is the primary method used to treat cancer in the clinic. Its goal is to deliver a precise dose to the planning target volume (PTV) while protecting the surrounding organs at risk (OARs). However, the traditional workflow used by dosimetrists to plan the treatment is time-consuming and subjective, requiring iterative adjustments based on their experience. Deep learning methods can be used to predict dose distribution maps to address these limitations. The study proposes a cascade model for organs at risk segmentation and dose distribution prediction. An encoder-decoder network has been developed for the segmentation task, in which the encoder consists of transformer blocks, and the decoder uses multi-scale convolutional blocks. Another cascade encoder-decoder network has been proposed for dose distribution prediction using a pyramid architecture. The proposed model has been evaluated using an in-house head and neck cancer dataset of 96 patients and OpenKBP, a public head and neck cancer dataset of 340 patients. The segmentation subnet achieved 0.79 and 2.71 for Dice and HD95 scores, respectively. This subnet outperformed the existing baselines. The dose distribution prediction subnet outperformed the winner of the OpenKBP2020 competition with 2.77 and 1.79 for dose and DVH scores, respectively. The predicted dose maps showed good coincidence with ground truth, with a superiority after linking with the auxiliary segmentation task. The proposed model outperformed state-of-the-art methods, especially in regions with low prescribed doses

Evaluation of Cancer Risk Induced by Radiation Exposure from Normal Head CT Scans

Purpose: Radiology examinations are growing significantly every year. Analysis of the CT scan reports can highlight defects and is a good way to develop safety in healthcare. This study aimed to evaluate the rate of normal head Computed Tomography (CT) scans at a hospital radiology department in Shahroud and estimate the cancer risk associated with these normal CT scans. Materials and Methods: In total, the data of 400 patients referred to the emergency radiology center of Imam Hossein hospital in Shahroud from November 23 to December 10, 2021, were collected. CT scan reports were categorized into three groups according to the interpretation of the radiologist. The BEIR VII model was used to estimate the radiation cancer risk. Results: Among the 400 patients, 248 (62%) were males and the average age of the patients was 49.05 ± 22.60 years. CT scans in 270 (67.5%) cases were reported normal. The average age of the patients with normal, and abnormal CT scans were 41.86 ± 20.27, and 63.03 ± 20.27 years, respectively and the difference was significant (p-value 10-year-old. The average risks of all solid cancers were 7.82 cases per 100,000 patients, while the average risk of leukemia was 0.71 cases per 100,000 patients. Conclusion: A large percentage of CT examinations are normal in our country which leads to many public health issues in the future years. Therefore, efforts should be made to establish predictor clinical factors to reduce unnecessary radiology examinations

Predkliničke studije [61Cu]ATSM kao PET radiofarmaka za snimanje fibrosarkoma

[61Cu]diacetyl-bis(N4-methylthiosemicarbazone) ([61Cu]ATSM) was prepared using in house-made diacetyl-bis(N4-methylthiosemicarbazone) (ATSM) ligand and [61Cu]CuCl2 produced via the natZn(p,x)61Cu (180 μA proton irradiation, 22 MeV, 3.2 h) and purified by a ion chromatography method. [61Cu]ATSM radiochemical purity was >98%, as shown by HPLC and RTLC methods. [61Cu]ATSM was administered into normal and tumor bearing rodents for up to 210 minutes, followed by biodistribution and co-incidence imaging studies. Significant tumor/non-tumor accumulation was observed either by animal sacrification or imaging. [61Cu]ATSM is a positron emission tomography (PET) radiotracer for tumor hypoxia imaging.[61Cu]diacetil-bis(N4-metiltiosemikarbazon) ([61Cu]ATSM) dobiven je iz liganda diacetil-bis(N4-metiltiosemikarbazona) (ATSM) pripravljenog u vlastitom laboratoriju i [61Cu]CuCl2 dobivenog iz natZn(p,x)61Cu (180 μA protonskim zračenjem, 22 MeV, 3.2 h). [61Cu]ATSM je čišćen ionskom kromatografijom. Prema HPLC i RTLC radiokemijska čistoća bila je > 98%. [61Cu]ATSM je davan zdravim glodavcima i glodavcima s tumorom tijekom 210 minuta te je praćena biodistribucija. Žrtvovanjem testiranih životinja te snimanjem primijećena je značajna razlika u akumulaciji [61Cu]ATSM u tumorskom tkivu u odnosu na zdravo tkivo. [61Cu]ATSM je pogodan za dijagnostiku hipoksije tumora pozitron emisijskom tomografijom (PET)

Assessment of Electromagnetic Fields around High Voltage Power Supply in Hamadan Hospital Wards

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Biological effects of non-ionizing radiation on the body of living organisms have been studied by researchers in recent years. High Voltage medical equipments are one of the sources generating electromagnetic fields. The electromagnetic field intensity of the medical equipment installed at Hamadan hospitals and the potential hazards were investigated. The main purpose of this study was to determine the intensity of the electromagnetic field around high voltage power supplies in radiology ward of the Hamadan hospitals. Materials and Methods: This was a cross-sectional study and we investigated the electromagnetic fields intensity around high voltage power supplies at Hamadan hospital wards. All measurements were performed using a calibrated Tesla-meter (HI-3603). The measurements were conducted at a range of distances varying from 25 cm to 3 m around the supporting high voltage power supply. Results: We found that the maximum intensity of the magnetic and electric fields at a distance of less than 1 m around the high voltage power supply was 29.625±5.738 mGauss and 25.17±0.92 V/m respectively, which is less than the safe amounts recommended by the ICNIRP for occupational exposure (5000 mG and 10000 V/m) and even for public exposure (1000 mG and and 5000 V/m). The minimum intensity of EM fields for a less than 3 m distance was found to be 0.1±0.005 mGauss, which relates to a CT-scanner system installed at Farshchian hospital. Among the whole equipments evaluated in the current survey, the most intense magnetic and electric field was found to be for imaging technician office, which was 3.050±0.004 mGauss and 128.88±0.05 V/m respectively; it is lower than the tolerances recommended by the ICNIRP. Conclusion: According to our results, it seems that the EM field occupational exposure for radiation workers working at Hamadan hospitals does not exceed the tolerances recommended by the ICNIRP. Therefore, we did not find any issue related to the over-irradiation of non-ionizing among the radiologists studied. It is recommended that different brands of generators to be used in order to conduct a detailed and comprehensive study to compare the intensity of the electrical and magnetic fields. st1":*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;