Deep-learned generation of renal dual-energy CT from a single-energy scan

AIM

To investigate the role of the deep-learning (DL) method in the generation of dual-energy computed tomography (DECT) images from single-energy images for precise diagnosis of kidney stone type.

MATERIALS AND METHODS

DECT of 23 patients was acquired, and the stone types were investigated based on the DECT software suggestions. The data were divided into two paired groups:120 kVp input and 80 kVp target and 120 kVp input and 135 kVp targets, p2p-UNet-GAN was exploited to generate the different energy images based on the common CT protocols.

RESULTS

The images generated of the generative adversarial network (GAN) network were evaluated based on the SSIM, PSNR, and MSE metrics, and the values were estimated as 0.85-0.95, 28-32, and 0.85-0.89 respectively. The attenuation ratio of test patient images were estimated and compared with real patient reports. The network achieved high accuracy in stone region localisation and resulted in accurate stone type predictions.

CONCLUSION

This study presents a useful method based on the DL technique to reduce patient radiation dose and facilitate the prediction of urinary stone types using single-energy CT imaging.

EFFECTIVE DOSE ESTIMATION IN WHOLE BODY 18F-FDG PET/CT IMAGING

Positron emission tomography-computed tomography (PET-CT) with internal administration of the FDG-18 is characterized as a widespread functional imaging modality in diagnostic radiation medicine, which increases the patient effective doses owing to the presence of internal and external radiation sources. Hence, patient effective dose estimation has been pinpointed as a significant factor in radiation protection assessment. A large number of studies have been published in this regard, and various dosimetry methods have been surveyed. According to our previous research, 10 patients had participated in PET-CT scans with three static time sequences imaging. PET effective doses were estimated using a simple method derived from Anderson et al. and Kaushik et al. coefficients, and the CT effective doses were surveyed with a CTDI phantom and cylindrical ionization chamber. The CT dose was tripled owing to the three static time-sequences imaging. The effective doses were calculated using different coefficients and the results of the PET effective doses were compared. The PET-CT effective dose was varied from 17.14 to 18.42 mSv based on Kaushik et al. coefficients which were measured for one low-dose CT scan. This study aimed to survey simple PET-CT effective dose estimation using three static-time imaging approaches which increases the total patient effective doses.

Wnt (canonical and non canonical) pathways in breast carcinoma with extensive vascular invasion and inflammatory breast carcinoma

BACKGROUND

Breast carcinoma with extensive peritumoral vascular invasion (ePVI-BC) is a cancer with massive vascular invasion (>10) detected in more than one slide. This neoplasm shows clinic-pathological affinity with inflammatory breast carcinoma (IBC). In this paper we evaluate their biological relationship through the study of surrogate markers (β-catenin and NFAT5) of Canonical (cWnt) and non-canonical (nWnt) Wnt pathways activation.

METHODS

By immunoistochemistry, we investigate β-catenin and NFAT5 in 39 IBC, 74 ePVI-BC and 84 control cases (CG-BC).

RESULTS

cWnt was activated in 100 % of ePVI-BC, in 64 % of IBC and 10 % of CG-BC. nWnt was activated in 20 % of ePVI-BC, 50 % of IBC and 1% of CG-BC. The prognosis of carcinomas with nWnt activated was poor similar to IBC. The statistical analysis evidences as both the pathways are synergistic in malignant progression and survival time. β-catenin show an important association with prognostic factors and NFAT5 shows a relevant prognostic role on OS (p = 1.5*10^-6) and DFS (P = 1,2*10^-4). nWnt is associated with a worse prognosis independently of cWnt. cWnt is associated with adverse prognosis (DFS p = 0.0469; OS p = 0.004891) but its prognostic role is indifferent in carcinoma with nWnt activated.

CONCLUSIONS

Canonical Wnt pathway is involved in malignant progression with dominant role for vascular invasion whereas non canonical Wnt pathway plays an important role on survival time including the capacity to identify carcinomas with IBC-like prognosis. Furthermore ePVI may represent a "prodromal form of IBC" as demonstrated by its clinicopathological and biological similarity with IBC.

Uterine PEComa with aggressive behavior: A review with an additional case of spontaneous vaginal expulsion

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor originating from perivascular epitheloid cells showing melanocytic and smooth muscle differentiation. The uterus represents the second most common site of origin. A 49 years woman presented to our Hospital for a vaginal spontaneous expulsion of a mass suggestive for malignant mesenchymal tumor. The patient underwent total hysterectomy and bilateral salpingo-oophorectomy and the histopathological report was compliant with a PEComa with aggressive behavior. Medical Literature databases about PEComa were searched. The current literature identified near 90 cases of uterine PEComas and they are categorized as uncertain malignant potential or with aggressive behavior. Primary surgical excision represents the gold-standard treatment. Recently targeted therapy with mTOR inhibitors has been introduced with an important beneficial. In this paper we review the Literature about the uPEComa with aggressive behavior reporting the first case of spontaneous vaginal expulsion.

MRS Shimming: An Important Point Which Should not be Ignored

BACKGROUND

Proton magnetic resonance spectroscopy (MRS) is a well-known device for analyzing the biological fluids metabolically. Obtaining accurate and reliable information via MRS needs a homogeneous magnetic field in order to provide well-defined peaks and uniform water suppression. There are lots of reasons which can disturb the magnetic field homogeneity which can be corrected by a process known as shimming. This study is intended to recall the importance of shimming and also the significant role of quality control (QC) in achieving an accurate quantification.

MATERIAL AND METHOD

An acrylic cylindrical quality control phantom was designed as an analog of brain MRS test phantoms in order to control the accuracy of the obtained signal of a 1.5 T Siemens MRI system which belonged to one of Shiraz hospitals. The signal of NAA, Cho, Cr, the combination of these metabolites and also the distilled water, which was used in this study, was evaluated using separate phantoms. A QC test was performed using Siemens QC phantom and a standard test phantom.

RESULTS

The spectrum of our home- made phantom had a significant difference with the expected spectrum. The results of checking the spectrum of metabolites separately also confirmed that there was a systemic problem that affects all the signals originated from all metabolites and even the pure distilled water. The MRS system could not pass QC tests, and peak broadening was common in all spectra. The complex spectrum of standard test phantom was not produced successfully by the MRS system.

DISCUSSION

By a simple check of the water peak characteristics, lots of information can be obtained, one of which is the status of shimming that has a considerable effect on the accuracy of the spectrum. Thus, performing an automatic or manual shimming is not a criterion of the spectrum accuracy, and performing a periodic quality control using a test phantom by a specialist is necessary.

CONCLUSION

Briefly, the quality control of MRS and all the other clinical device must be taken seriously. Sometimes QC can be the boundary of a right or a wrong decision for the patient.

Oil Red O Is a Useful Tool to Assess Donor Liver Steatosis on Frozen Sections During Transplantation

Oil Red O is a useful tool to assess donor liver steatosis on frozen sections during transplantation. Steatosis is a frequent finding in liver evaluation during transplantation, accounting for 9% to 26% of biopsied donor liver. The degree of macrovesicular steatosis is classified as mild, moderate, and severe; the latter is considered an absolute contraindication to liver transplantation because it is associated with poor allograft outcome. Because of the scarcity of organs, there is a debate whether livers with less severe macrovesicular steatosis are still suitable for transplant. Consequently, tools or methods that allow a more accurate intraoperative assessment of steatosis on frozen sections are mandatory. The aim of this study is to improve intraoperative evaluation of steatosis during transplantation using Oil Red O stain on liver biopsies.

METHODS

Twenty consecutive liver biopsies of donors were collected during transplantation procedures from September 2017 to February 2018 at the Institute of Pathology of the University and Hospital Trust of Verona, Italy. Each liver biopsy was cut at a different thickness (3, 5, and 8 μm) and stained with both Oil Red O and conventional hematoxylin and eosin for intraoperative consultation. The degree (percentage of hepatocytes involved) of fatty changes was recorded. The results obtained during the intraoperative consultation were finally compared with the formalin-fixed and paraffin-embedded permanent section.

RESULTS

Assessment of steatosis on hematoxylin and eosin frozen sections was reported as mild in 17 cases (85%), moderate in 2 cases (10%) and severe in 1 case (5%). Oil Red O frozen sections reported the following results: mild steatosis in 16 cases (80%), moderate in 2 cases (10%), and severe in 2 cases (10%). The percentage of liver steatosis obtained with Oil Red O was consistent in all cases with that of the permanent sections. The staining procedure for Oil Red O required approximately 18 minutes.

CONCLUSIONS

Oil Red O special stain is a fast and inexpensive tool to improve the assessment of steatosis on frozen biopsies during liver transplantation.

Effect of age-dependent bone electron density on the calculated dose distribution from kilovoltage and megavoltage photon and electron radiotherapy in paediatric MRI-only treatment planning

OBJECTIVE

MRI-only treatment planning (TP) can be advantageous in paediatric radiotherapy. However, electron density extraction is necessary for dose calculation. Normally, after bone segmentation, a bulk density is assigned. However, the variation of bone bulk density in patients makes the creation of pseudo CTs challenging. This study aims to assess the effects of bone density variations in children on radiation attenuation and dose calculation for MRI-only TP.

METHODS

Bone contents of <15-year-old children were calculated, and substituted in the Oak Ridge National Laboratory paediatric phantoms. The percentage depth dose and beam profile of 150 kVp and 6 MV photon and 6 MeV electron beams were then calculated using Xcom, MCNPX (Monte Carlo N-particle version X) and ORLN phantoms.

RESULTS

Using 150 kVp X-rays, the difference in attenuation coefficient was almost 5% between an 11-year-old child and a newborn, and ~8% between an adult and a newborn. With megavoltage radiation, the differences were smaller but still important. For an 18 MV photon beam, the difference of radiation attenuation between an 11-year-old child and a newborn was 4% and ~7.4% between an adult and a newborn. For 6 MeV electrons, dose differences were observed up to the 2 cm depth. The percentage depth dose difference between 1 and 10-year-olds was 18.5%, and between 10 and 15-year-olds was 24%.

CONCLUSION

The results suggest that for MRI-only TP of photon- or electron-beam radiotherapy, the bone densities of each age group should be defined separately for accurate dose calculation. Advances in knowledge: This study highlights the need for more age-specific determination of bone electron density for accurate dose calculations in paediatric MRI-only radiotherapy TP.

Developing light nano-composites with improved mechanical properties for neutron shielding

Although radiation exposures in manned space missions are normally below the limits recommended to NASA by NCRP, in long-duration deep space exploratory missions astronauts may receive relatively high doses of ionizing radiation. Novel light polyethylene-based composites can be considered as effective radiation shields in space explorations. However, normally these composites cannot provide desired mechanical properties. Over the past several years our laboratories have focused on developing efficient methods for both physical and biological protection of the crew in long term space missions. In this study carbon nanotubes and either nano-sized or micro-sized boron carbide (B4C) fillers were incorporated into the continuous phase of low density polyethylene (LDPE). In the next phase, the mechanical characteristics of the composites as well as their neutron attenuation properties were studied. Findings of this study indicated enhanced mechanical properties accompanied by an enhanced shielding efficiency for neutrons at some specific weight fraction of the fillers.

Measurement of the Dose to the Family Members Taking Care of Thyroid Cancer Patients Undergoing I-131 Therapy in Nuclear Medicine Using TLD-100

The family members or friends of the patients undergoing treatment using radioiodine in nuclear medicine are inevitably exposed to ionization radiation. The purpose of this study is measurement of the dose received by the people taking care of the thyroid cancer patients treated by 131I. For this purpose, the dose amounts received by 29 people accompanying patients were measured using thermoluminescence dosimeters. A badge containing three TLD-100 chips was given to each caregiver. The people were asked to wear the badges for 24 days, when they are taking care of the patients. Finally the dose to each person was estimated by averaging the readings of the three TLDs. The measured dose amounts to the people were compared with the recommendations of international commitions. According to the results obtained in this study, the amounts of dose received by the caregivers were between 0.03 and 0.38 mSv, with the average of 0.12 mSv. By comparison of the results of this study with the recommendations of International Commission on Radiological Protection (ICRP), it can be observed that the dose to family members of the patients is less than the dose constraints. However, it is recommended that the caregivers be aware of the radiation protection principles in order to reduce their dose.

Investigation of LiF, Mg and Ti (TLD-100) Reproducibility

LiF, Mg and Ti cubical TLD chips (known as TLD-100) are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy) with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC) were obtained 4 times by irradiating them to doses of 81 mGy (two times), 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

Does Occupational Exposure of Shahid Dastghieb International Airport Workers to Radiofrequency Radiation Affect Their Short Term Memory and Reaction Time?

BACKGROUND

Airport workers are continuously exposed to different levels of radiofrequency microwave (RF/MW) radiation emitted by radar equipments. Radars are extensively used in military and aviation industries. Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. The main goal of this study was to investigate if occupational exposure of Shahid Dastghieb international airport workers to radiofrequency radiation affects their short term memory and reaction time.

METHODS

Thirty two airport workers involved in duties at control and approach tower (21 males and 11 females), with the age range of 27-67 years old (mean age of 37.38), participated voluntary in this study. On the other hand, 29 workers (13 males, and 16 females) whose offices were in the city with no exposure history to radar systems were also participated in this study as the control group. The employees' reaction time and short term memory were analyzed using a standard visual reaction time (VRT) test software and the modified Wechsler memory scale test, respectively.

RESULTS

The mean± SD values for the reaction times of the airport employees (N=32) and the control group (N=29) were 0.45±0.12 sec and 0.46±0.17 sec, respectively.  Moreover, in the four subset tests; i.e. paired words, forward digit span, backward digit span and word recognition, the following points were obtained for the airport employees and the control group, respectively: (i) pair words test: 28.00±13.13 and 32.07±11.65, (ii) forward digit span: 8.38±1.40 and 9.03±1.32, (iii) backward digit span: 5.54±1.87 and 6.31±1.46, and (iv) word recognition: 5.73±2.36 and 6.50±1.93. These differences were not statistically significant.

CONCLUSION

The occupational exposure of the employees to the RF radiation in Shahid Dastghieb international airport does not have any significant detrimental effect on their reaction time as well as short term memory.

Investigation of the entrance surface dose and dose to different organs in lumbar spine imaging

BACKGROUND

Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology.

OBJECTIVE

The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views.

METHODS

To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging.

RESULTS

The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement.

CONCLUSION

According to the results, the GR200 has greater sensitivity than the TLD-100.

Subglotic malt-lymphoma of the larynx: an unusual presentation of chronic cough

Extranodal non-Hodgkin lymphomas limited to the larynx are rare, accounting for less than 1% of all laryngeal neoplasms. The most common site of development of primary laryngeal lymphomas is the supraglottic region. In most cases, the presenting symptoms are hoarseness, dysphagia, dyspnea, and cervical lymphadenopathy. They consist mainly of non-Hodgkin lymphoma, especially of diffuse large B-cell lymphoma and mucosa-associated lymphoid tissue. We report a case of a primary extranodal marginal zone of mucosa-associated lymphoid tissue (Malt Lymphoma) of the larynx in a 73-year-old non-smoker woman, presented as chronic cough, unresponsive to oral corticosteroid. We present a detailed report of her clinical and paraclinical data as well as treatment options. In patients with chronic cough, uncommon causes should be considered when the cough persists after evaluation for common causes. If a cough persists after consideration of the most common causes, CT scan and a bronchoscopic evaluation are fundamental for the diagnosis of tumors of the upper and lower respiratory tract.

Independent evaluation of an in-house brachytherapy treatment planning system using simulation, measurement and calculation methods

Accuracy of treatment planning systems may significantly influence the efficacy of brachytherapy. The purpose of this work is a detailed, varied and independent evaluation of an in-house brachytherapy treatment planning software called STPS. Operational accuracy of STPS was investigated. Geometric tests were performed to validate entry and reconstruction of positional information from scanned orthogonal films. MCNP4C Monte Carlo code and TLDs were used for simulation and experimental measurement, respectively. STPS data were also compared with those from a commercial planning system (Nucletron PLATO). Discrepancy values between MCNP and STPS data and also those of PLATO and STPS at Manchester system dose prescription points (AL and AR) of tandem and ovoid configurations were 2.5% ± 0.5% and 5.4% ± 0.4%, respectively. Similar results were achieved for other investigated configurations. Observed discrepancies between MCNP and STPS at the dose prescription point and at 1 cm from the tip of the vaginal applicator were 4.5% and 25.6% respectively, while the discrepancy between the STPS and PLATO data at those points was 2.3%. The software showed submillimeter accuracy in its geometrical reconstructions. In terms of calculation accuracy, similar to PLATO, as attenuation of the sources and applicator body is not considered, dose was overestimated at the tip of the applicator, but based on the available criteria, dose accuracy at most points were acceptable. Our results confirm STPS's geometrical and operational reliability, and show that its dose computation accuracy is comparable to an established commercial TPS using the same algorithm.

Natural and artificial radioactivity distribution in soil of Fars Province, Iran

Fars province is a large populated large province located in the southwest of Iran. This work presents a study of natural and radioactivity levels in soil samples of this province. For this purpose, 126 samples were gathered from different regions of the province and analysed by gamma spectroscopy to quantify radioactivity concentrations of radionuclides using a high-purity germanium detector and spectroscopy system. The results of this investigation show the average concentrations of 271 ± 28 Bq kg(-1), 6.37 ± 0.5 Bq kg(-1), 14.9 ± 0.9 Bq kg(-1) and 26.3 ± 1.9 Bq kg(-1) for (40)K, (137)Cs, (232)Th and (238)U in soil, respectively. Finally, baseline maps were established for the concentrations of each of the radionuclides in different regions. The absorbed dose rate and the annual effective dose (AED) were also calculated for the radionuclides according to the guidelines of UNSCEAR 2000. The average AED from the radioactivity content of soil in this province was found to be 39.9 ± 1.8 μSv.