Iranian Journal of Medical Physics
Volume:20 Issue: 6, Nov-Dec 2023

This study evaluated the efficacy of Markhamia tomentosa (MT) extract as a potential radiation countermeasure emphasising its radioprotective and radiomitigating properties. Forty male albino Wistar rats aged 10-12 weeks were used for the study. Rats were divided into eight groups comprising five animals in each group. The extract was administered for 14 days by oral gavage for both pretreatment and post-treatment. An hour after the last pre-administration, animals received 3 Gy and 6 Gy of gamma radiation by whole-body irradiation (WBI) using 60Co-γ as the radiation source. Rats were euthanised on day 15 for hematological and histological examinations except those in post-treatment groups. Data were analysed by one-way ANOVA and subjected to Tukey's HSD post hoc test. WBI of rats at 3 Gy and 6 Gy significantly reduced the hematological parameters. However, the oral administration of MT extract ameliorated the effect of ionising radiation by considerably improving the hematological parameters leading to high blood counts. Continuous administration of MT extract for additional 14 days showed a more remarkable improvement in the hematological parameters, as evident in the white blood cell, neutrophils and platelet counts. Pre and post-treatment of rats with MT extract decreased changes in the kidney tubules, and the liver showed moderate congestion of hepatic sinusoids in the portal tracts denoting an increased blood flow rate causing healing of the cells. MT demonstrated its radioprotective and radiomitigating potential in recovering distorted tissues and modulating the effects of gamma radiation-induced damage to blood cells.

This study aimed to compare the image quality and volume dose index of head CT scan between two adaptive statistical iterative reconstructions (ASIR) and the filtered back projection (FBP) algorithms. CT number, noise and signal to noise ratio(SNR) for white matter(WM), gray matter(WM), cerebrospinal fluid(CSF( and skull bone were investigated in brain CT scans of 60 patients. All images were reconstructed by FBP and ASIR 40% algorithms. A water phantom was also used to compare the average CT number; noise, signal-to-noise (SNR), and contrast-to-noise ratio (CNR) between algorithms under different acquisition parameters. Volume computed tomography dose index (CTDIvol) and (dose-length product) DLP were obtained from scanner software. Data were analyzed by T-test and Mann-Whitney statistical test with a significance level of less than 0.05. Image noise of gray matter, CSF and skull bone was significantly lower for ASIR algorithm (P<0.05). The difference in SNR for white matter and gray matter was not significant between the two algorithms but it was higher for CSF and bone for ASIR. In phantom study, Image noise, CTDIvol and DLP in both axial and spiral scan modes were higher for FBP algorithm (P<0.05). In addition, there was no significant difference in SNR and CNR between the two algorithms (P>0.05). ASIR algorithm reduces the dose and image noise in head CT scan compared to the filtered back projection. In addition, using ASIR algorithm the image noise does not increase with lower mA.

Dose planning is one of the important steps for the effective implementation of radiotherapy. As recommended, 95% to 107% of the prescribed dose should cover the target volume. Thus, radiotherapy cannot improve patient outcomes unless the desired dose delivery accuracy is achieved. The study was performed to evaluate field-in-field (FIF) technique (Forward intensity-modulated radiotherapy) compared with 3D-conformal radiotherapy enhanced dynamic wedge (EDW) technique. Two plans with opposed tangential fields; FIF and EDW for each breast cancer patient were created. The two techniques were comparable as far as the , D2%, and D5% were concerned. However, the FIF plan was slightly superior to EDW as far as D95% and D98% were concerned. The V95% was slightly higher in favor of FIF technique. The superiority of the FIF technique was further demonstrated by the lower mean dose (Dmean) and the volumes receiving 10 Gy (V10Gy) and 20 Gy (V20Gy) of the prescribed dose for the heart. The Dmean, V5Gy, V10Gy, and V20Gy for ipsilateral and contralateral lungs were comparable between the two techniques. However, the FIF technique demonstrated higher Dmean to the contralateral breast than EDW technique. These results along with experiences elsewhere show the dosimetric benefits of the FIF technique for the optimal dose that should cover the target volume. However, the higher Dmean to the contralateral breast was a substantial shortcoming for the FIF technique. It can be recommended that the two planning techniques can be combined and used together to cover their drawbacks.

During the treatment of soft tissue tumors with high-intensity focused ultrasound (HIFU), the focus may shift away from the desired point due to tissue heterogeneity. By studying the effect of biological tissue on focus shift, it can provide a theoretical basis for the safety and reliability of HIFU therapy.
The finite difference time domain (FDTD) method was used to construct the simulation model of HIFU irradiated multi-layer biological tissue. Based on the Westervelt nonlinear acoustic propagation equation, the focus position change caused by the thickness of biological tissue and ultrasonic transducer during HIFU irradiation were simulated and calculated. The effects of ultrasonic transducer's electric power, irradiation frequency and tissue thickness on the focus position shift were analyzed and discussed.
With the increase of electric power of HIFU transducer, the sound pressure at the focal point rose and the focal point approached the transducer side. With the increase of irradiation frequency of transducer, the sound pressure at the focus increased and the focus shifted away from transducer. With the increase of the thickness of biological tissue, the amplitude of sound pressure at the focal point decreased gradually. If the sound velocity of biological tissue was greater than that of water, the focus was close to the transducer side. If the sound velocity of biological tissue was less than the sound velocity of water, the focus moved to the side away from the transducer. For biological tissue with sound velocity greater than (or less than) water, the greater the sound velocity, the greater the relative shift distance difference of focal position.
As the electric power and frequency of ultrasonic transducer increased, the focus of HIFU moved toward and away from the transducer, respectively. For multi-layer biological tissue, the focus shift direction depended on the sound velocity relationship between biological tissue and water

Health examinations are performed every six months. X-rays, magnetic resonance imaging (MRI), ECGs, and blood tests are all part of health examinations. In this investigation, the silent T2 Fast-Spin-Echo (FSE) and Gradient-Recalled Echo (GRE) MRI head examination sequences are compared. Noise is produced during an MRI test in addition to images.
This research was conducted by adjusting the parameters on the MRI, such as time repeat (TR), time echo (TE), and echo train length (ETL). Then, the resulting silent sequence image is simulated with a simulation program.
The variation of TR 440 with TE 24 in the GRE sequence for the white matter (WM) tissue has the highest signal to noise ratio (SNR) value. The cerebispinal fluid (CSF) tissue is also in the TR 560/TE 20 variant at the same time. Then, variations of TR 3360, TE 97, and ETL 33.6 have the highest peak signal to noise ratio (PSNR) measurement results in the WM or CSF tissue.
According to the study's findings, the average sound intensity level and mean square error (MSE) value produced by the GRE sequence protocol are less than those produced by the T2 FSE sequence protocol. While this is the case, the GRE sequence protocol generates an average PSNR value that is higher than the FSE T2 sequence protocol. The T2 FSE sequence with variations of TR 3360, TE 97, and ETL 33.6 may then be observed to be the best with the ideal noise level and SNR value.

This study aimed to evaluate the dosimetric variations and treatment efficacy between intensity-modulated radiotherapy (IMRT) and double-arc RapidArc for irradiation of carcinoma left breast, focusing on adequate target coverage, sparing of organs at risk (OARs), delivered monitor units (MUs) per fraction, and treatment delivery time. This prospective, observational study was conducted on 30 patients with carcinoma left breast. All these patients were treated with adjuvant radiation therapy.  We generated two plans for each of these patients: IMRT and double-arc RapidArc technique. The target volume and OARs were analyzed using dose-volume histograms (DVHs). The average MUs and the treatment time were used as markers to assess the efficacy of treatment delivery. The planning target volume parameters such as homogeneity and conformity index were similar for all the plans with both techniques. With IMRT, statistically significantly better sparing of I/L lung, heart, C/L breast, C/L lung, and esophagus were achieved as compared to RapidArc. We found that RapidArc resulted in significantly lower MUs (535.05 ± 105.42) than IMRT (913.57 ± 129.35). Treatment delivery time was statistically shorter with RapidArc as compared to IMRT (p=0.001).  This study concluded that both IMRT and RapidArc plans have similar target coverage in terms of homogeneity and conformality indexes. Better OARs sparing was noticed with IMRT while RapidArc enabled higher efficacy with lower MUs and shorter treatment delivery time. However, further studies are needed to establish these dosimetric advantages being translated to improvements in the clinical outcomes of these patients.

Biological effects after a single prenatal exposure to ionizing radiation, reflecting significant heterogeneities in the responses in different species with respect to radiation type, dose, dose rate and time of exposure. Moreover, current knowledge and obtained results for poultry exposed to low dose ionizing radiation are inconsistent and almost lacking at present. The aim of this study was to determine the effect of low dose gamma radiation on protein profile in blood of chickens irradiated in ovo. 
Fertilized chicken eggs in the experimental group were exposed to 0.3 Gy gamma radiation one hour before incubation, and control group was sham irradiated. Blood samples were taken on 1st, 3rd, 5th, 7th and 10th days of life. The plasma proteins fractions were separated by electrophoresis, while total protein and albumin levels were determined using the spectrophotometric method.
The obtained differences between control and experimental groups for total protein and albumin concentrations were statistically nonsignificant during our research. Total globulins were increased 10th day of chick’s life due to an increase in alpha globulins (P < 0.05). In contrast, gamma globulins were decreased in one-day-old chickens exposed to ionizing radiation (P < 0.05).
Our study indicates a significant effect of low-dose ionizing radiation on protein synthesis after in ovo exposure, although more research is needed to determine underlying molecular mechanisms triggered by low-dose gamma radiation.

This study compares three dimensional conformal radiotherapy (3DCRT) and Posterior Partial Arc volumetric modulated arc therapy (VMAT) planning techniques for treating craniospinal irradiation.  Ten patients with Medulloblastoma were retrospectively considered for the study and replanned using 3DCRT and posterior partial arc VMAT techniques using MONACO 5.11, treatment-planning system (TPS). The dose prescribed for the planning target volume (PTV) was 36Gy in 20 Fractions, followed by a boost dose to the brain volume. The parameters such as Tumour coverage, the organ at risk (OAR) doses, conformity index (CI), homogeneity index (HI), and total monitor units (MU) were calculated for both plans. Comparison of the two planning techniques done using paired sample t-test.
PTV coverage in VMAT and 3DRT was 97.994±2.2533 and 94.041±2.24907, respectively. The mean CI in 3DCRT and VMAT was 1.3459±0.3279 and 1.1714±0.1238, respectively, and the mean HI in 3DCRT and VMAT was 1.1151±0.0247 and 1.0634±0.0198, respectively. OAR doses were comparable in 3DCRT and VMAT. The total MU in 3DCRT and VMAT were 198.12±8.9539 and 978.403±170.0104, respectively.
Posterior Partial Arc VMAT plans are superior to 3DCRT in target coverage, conformity index, and homogeneity index. The OAR doses in the two planning techniques were comparable whereas, the duration of treatment was higher in VMAT compared to the 3DCRT method. Additionally, low dose volumes are reduced in VMAT due to partial posterior arcs. Considering all the factors, it can be concluded from the study that Posterior Partial Arc VMAT plans are superior to 3DCRT.