How much is the effective dose from medical imaging in pediatric patients in the neurosurgery department?

Medical imaging with ionizing radiation in pediatric patients is rising, and their radiation sensitivity is 2–3 times more than adults. The objective of this study was to estimate the total effective dose (ED) of all medical imaging by CT scan and plain radiography in patients in pediatric neurosurgery department. Patients with at least one brain CT scan and recorded dose length product (DLP) were included. Patients’ imaging data were collected from the picture-archiving-and-communicating system (PACS) using their national code to find all their medical imaging. Total ED (mSv) from CT scans and plain radiographs were calculated. A total of 300 patients were included, of which 129 were females and 171 males with a mean age of 5.45 ± 4.34 years. Mean DLPs of brain, abdomen, and chest CT were 329.16, 393.06, 284.46 mGy.cm. The most frequent CT scans in these children were brain CT scans with ED range of 0.09 to 47.09 mSv. Total ED due to all CT scans and plain radiographs were in the range of 0.38 to 63.41 mSv. Although the mean DLP of each brain, chest, and abdomen CT of patients was in the range of DRLs reported by previous studies, the patients with numerous CT scans received more radiation doses than mean ED (6.21 mSv between all age groups). The most frequent CT scan was the brain, and the most frequent plain radiographs were chest and lower extremities. It can be concluded that reducing the number of CT scans or plain radiographs by appropriate physical exams or replacing them with modalities that do not use ionizing radiation can reduce ED

Evaluation of influencing factors on the radiation dose of hospitalized neonates: Maturity status and type of disease

Context: Premature neonates have multiple medical and surgical problems; therefore, hospitalization and imaging are required. Recently there has been too much concern about the long-term effects of radiation in neonates. In this survey, we assessed the frequency of imaging and radiation dose in neonates hospitalized in neonatal intensive care unit (NICU) in our University-affiliated hospital. Materials and methods: This was a retrospective cross-sectional study conducted during a year (2019–2020) on 291 neonates. The information has been gathered from Health Information System and picture archiving and communication system, and analyzed with SPSS version 22. Results: 291 neonates were included in the study, from which 175 (60%) neonates were preterm and 116 (40%) neonates were term neonates. The mean gestational age (GA) was 35.5 weeks and the mean hospital admission duration was 15.8 days. The mean number of portable and non-portable imaging procedures was 5.13 and 0.62 for preterm and term neonates, respectively. There is a statistically significant relationship between gastrointestinal disease and the number of abdominal X-rays. There is also a statistically significant relationship between acute respiratory distress syndrome (ARDS) and chest X-rays; there is no statistically significant relationship between pneumonia and the number of chest X-rays in the hospital course. The mean accumulation effective doses in preterm and term neonates in-hospital course were 0.549 and 0.498 mSv, respectively. Discussion: The neonates in NICU are more susceptible to radiation hazards due to numerous imaging than other neonates. Portable imaging is eight times more dosing than non-portable imaging, so due to the scattered radiation from portable devices, the actual radiation dose may be higher than what we estimated. No brain CT scan was done for the neonates with convulsion because of using safer and more valuable modalities; so we could recommend radiologists and pediatrics to use substitute modalities like sonography and MRI instead of CT scan and X-rays

Application of mobile X-ray barriers during angiography procedure: how much is it effective? A case study

Introduction: This study intended to assess the effectiveness of application the mobile X-ray barriers (lead-wall) in reducing the radiation dose to interventionists during the brain angiography procedures. Moreover, the radiation dose of patients also evaluated to assess whether the application of lead-wall affects the patient’s dose or not? Material and method: Two interventionists took part in this study. Thermoluminescent dosimeters (TLD-100) were used to monitor the doses to interventionists. 1st-interventionist routinely used lead-wall and 2nd-interventionist didn’t use it. Demographic information of patients and radiation dose information was also recorded. Results: The results of measurements showed that the radiation dose of the 1st-interventionist was 83.57% lower than the 2nd-interventionist (p = 0.04). The amount of dose/min and DAP/min of the 1st-interventionist’s patients were 33.50% and 17.54% less than the 2nd-interventionist’s patients (p = 0.006) and (p = 0.0004). Discussion and conclusion: The results showed that application of lead wall can effectively reduce the occupational dose and it doesn’t lead to increase the patient’s dose

Fast and accurate Monte Carlo modeling of a kilovoltage X-ray therapy unit using a photon-source approximation for treatment planning in complex media

To accurately recompute dose distributions in chest-wall radiotherapy with 120 kVp kilovoltage X-rays, an MCNP4C Monte Carlo model is presented using a fast method that obviates the need to fully model the tube components. To validate the model, half-value layer (HVL), percentage depth doses (PDDs) and beam profiles were measured. Dose measurements were performed for a more complex situation using thermoluminescence dosimeters (TLDs) placed within a Rando phantom. The measured and computed first and second HVLs were 3.8, 10.3 mm Al and 3.8, 10.6 mm Al, respectively. The differences between measured and calculated PDDs and beam profiles in water were within 2 mm/2% for all data points. In the Rando phantom, differences for majority of data points were within 2%. The proposed model offered an approximately 9500-fold reduced run time compared to the conventional full simulation. The acceptable agreement, based on international criteria, between the simulations and the measurements validates the accuracy of the model for its use in treatment planning and radiobiological modeling studies of superficial therapies including chest-wall irradiation using kilovoltage beam

MRS Shimming: An Important Point Which Should not be Ignored

Introduction: 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