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Forward planned intensity-modulated radiotherapy (forward IMRT) with breath-hold (BH) technique is considered optimal by most practitioners for treating left-sided breast cancer. Regional nodal irradiation including axilla and supraclavicular fossa (SCF) increases can increase dose-to-organs at risk (OAR) especially lung. This study was done to assess the potential of inverse planned IMRT (inverse IMRT) to achieve significant reduction in dose to OAR.
Ten patients with left-sided breast cancer treated with Active Breath Co-ordinator BH technique were included in the study. Forward IMRT plans were generated in both BH and free breathing (FB) scans. Inverse IMRT plans were generated in FB scan using Tomotherapy-Direct and Tomotherapy-Helical techniques. Contouring was done as per the ESTRO consensus contouring guidelines. The dose prescribed was 40 Gy in 15 fractions. Statistical significance was tested using one-way ANOVA for parametric data and Kruskall-Wallis test for nonparametric data. Multiple comparison tests were done by using Bonferroni test.
<0.05 was considered to denote statistical significance.
Inverse IMRT plans achieved superior homogeneity index compared to forward IMRT with BH. Tomotherapy-Direct reduced dose to ipsilateral lung, compared to the forward IMRT with BH while achieving similar doses to other OAR. Tomotherapy-Helical plans achieved significantly better conformity index and reduced maximum dose to left anterior descending artery compared to forward IMRT plans, but low dose to other OAR was significantly worse.
For left-sided breast, axilla, and SCF radiotherapy, inverse IMRT with Tomotherapy-Direct plan achieved better homogeneity index and reduced dose to ipsilateral lung compared to forward IMRT with BH.
For left-sided breast, axilla, and SCF radiotherapy, inverse IMRT with Tomotherapy-Direct plan achieved better homogeneity index and reduced dose to ipsilateral lung compared to forward IMRT with BH.
Quality assurance of linear accelerators (linacs) is an important part of ensuring accurate radiotherapy treatment deliveries. The aim of this study is to investigate the role of gravity on the positional accuracy of multileaf collimator (MLC) leaves during complex radiotherapy treatments on linacs. This investigation is based on the analysis of the machine log files from five different linacs in multiple centers.
Three main categories of deliveries were considered Picket fence, volumetric modulated arc therapy (VMAT) (both delivering with continuous gantry rotation), and sliding gap tests delivered at cardinal gantry angles, to determine the error of the MLC in relation to the gantry angle.
Analysis of picket fence tests revealed a dependence of the error upon the gantry angle. selleck kinase inhibitor For the majority of deliveries, the MLC showed greater error at gantry angles 270 and 90. The errors computed for the cardinal angles for sliding gap tests were all statistically different with greatest error arising at gantry angle 270 and least error at gantry 90. For picket fence, sliding gap, and VMAT cases, MLC errors were dependent on the gantry angle.
The errors in leaf positioning were found to be dependent on the gantry angle. For sliding gap tests, the error was greater at gantry angle 270° and 90° and less when the leaf motion was perpendicular to the force of gravity.
The errors in leaf positioning were found to be dependent on the gantry angle. For sliding gap tests, the error was greater at gantry angle 270° and 90° and less when the leaf motion was perpendicular to the force of gravity.
Ionizing radiation has been extensively used for medical diagnosis since its discovery in 1895; however, excessive use can lead to deleterious effects. Prior knowledge on radiological protocols based on simulations would be a practical tool for optimal use of radiation.
Scan length of the thorax was measured from computed tomography (CT) topographic images and cross-sections at three levels of the thorax were measured from tomographic images of 500 adults and 340 children who had undergone CT thorax examinations using Centricity workstation software. The effective diameter (ED) of the thorax was calculated from anterio-posterior (AP) and transverse anatomical dimensions.
A 17% increase in scan length was observed for 6-10 years age group compared to 0-5 years, whereas there was marginal increase for 11-15 years of age. A 11.5% increase was observed for 16-18 years compared to 11-15 years age group. The cross-sectional phantom dimensions were calculated from ED measurements obtained from three regions of the thorax.
This study has provided age- and gender-specific reference scan lengths, AP and transverse dimensions and ED for radiological examinations of the thorax. This information is useful to develop age- and gender-specific preset protocols and fabricate phantoms of the thorax for the pediatric and adult Indian population.
This study has provided age- and gender-specific reference scan lengths, AP and transverse dimensions and ED for radiological examinations of the thorax. This information is useful to develop age- and gender-specific preset protocols and fabricate phantoms of the thorax for the pediatric and adult Indian population.
To determine the multileaf collimator positional error (MLC-PE) during volumetric modulated arc therapy (VMAT) delivery by studying the time-dependent MLC velocity in mathematically derivable trajectories such as straight line and conic sections.
VMAT delivery is planned in a way that MLCs are moving in a locus which can be defined by mathematical functions such as linear, parabolic, or circular velocity (PV or CV). The VMAT delivery was interrupted either once or multiple times during the delivery and projection images of the same were acquired in electronic portal imaging device. MLC-PE was then analyzed as a function of dose rate (DR), and MLC speed (SP) and number of interruptions in treatment delivery. In VMAT delivery with linear MLC motion, the delivery was interrupted either once (linear motion single interruption) or multiple (three) times (linear motion multiple interruptions). For PV and CV MLC velocity, the MLC motions are interrupted multiple times.
The maximum individual error obtained (DRsm.
The aim of the radiotherapy is to deliver a lethal dose to tumor while reducing the impact on the normal tissue. This reduction in impact can be achieved to have a greater therapeutic ratio by using nanoparticles as radiosensitizer.
In this article, the potential role of superparamagnetic iron oxide nanoparticles (SPIONs) as radiosensitization enhancer on HT 29 cell lines for different concentrations (0.007to 0.25 mg/ml) and different radiation doses (0.5to 2 Gy) of 6MV photon beam is presented.
The highest sensitization enhancement ratio (SER) value was observed with 2 Gy for 0.25 mg/ml concentration. Radio sensitization increases with increase in the concentration of nanoparticles. Combination of 6MV energy radiation and polyethylene glycol (PEG) coated SPIONs results in increasing cell killing of HT 29 as compared to cell killing with radiation therapy alone.
The results reveal that PEG coated nanoparticle might be a potential candidate to work as radiotherapy sensitizer in colorectal cancer.
The results reveal that PEG coated nanoparticle might be a potential candidate to work as radiotherapy sensitizer in colorectal cancer.
The proposed technique uses the edge-preserving capabilities of cross-bilateral filter (CBF) and artificial intelligence technique adaptive neuro-fuzzy inference system (ANFIS) to fuse multi-modality medical images.
The aim is to present the unlike information onto a single image as each modality of medical image contains the unalike domain of information.
First, the multi-modality medical images are decomposed using CBF by tuning its parameters radiometric and geometric sigma producing CBF component and detail component. This detail is fed to ANFIS for fusion. On the other hand, the sub-bands obtained from DWT are fused using average rule. Reconstruction method gives final image.
ANFIS is used to train the Sugeno systems using neuro-adaptive learning. The fuzzy inference system in the ANFIS is used to define fuzzy rules for fusion. On the other hand, bior2.2 is used to decompose the source images.
The performance is verified on the Harvard database with five cases, and the results are equated with conventional metrics, objective metrics as well as visual inspection. The statistics of the metrics values is visualized in the form of column chart.
In Case 1, better results are obtained for all conventional metrics except for average gradient (AG) and spatial frequency (SF). It also achieved preferred objective metric values. In Case 2, all metrics except AG, mutual information, fusion symmetry, and SF are better values among all methods. In Cases 3, 4, and 5, all the metrics have achieved desired values.
Experiments conclude that conventional, objective, visual evaluation shows best results for Cases 1, 3, 4, and 5.
Experiments conclude that conventional, objective, visual evaluation shows best results for Cases 1, 3, 4, and 5.
In this study, we hypothesize that exposure of adipose tissue-mesenchymal stem cells (AT-MSCs) to electromagnetic field (EMF) may impact adipose stem cells' micromolecular structure (analyzed using Fourier transform infrared spectroscopy [FTIR]).
The AT-MSCs were exposed to continuous vertically applied sinusoidal EMF with a frequency of 50 Hz and a flux density of 1.5 mT for 24, 48, and 72 h. After an appropriate time (24, 48, 72 h) cells were washed with PBS, scrubbed, and immediately taken into FTIR analyses.
EMFs affect AT-MSCs. The greatest differences were in the range of nucleic acids and proteins in the fingerprint region which occurred after 24 and 48 h of EMF exposure. However, in the case of 72 h of EMF exposure, no significant differences were noticed in the FTIR spectra towards the control.
FTIR spectra show differences between samples under the influence of EMF before they will be manifested at the morphological level. The largest differences in the range of nucleic acids and proteins in. EMF is not neutral for stem cells, especially in the in the first hours of interaction (24 h, 48 h).
The preferred radiotherapy treatment for medulloblastoma is craniospinal irradiation (CSI). With the aim of developing the potential to reduce normal tissue dose and associated post-treatment complications with photon and proton radiotherapy techniques for CSI. This report aims to carefully compare and rank treatment planning and dosimetric outcomes for pediatric medulloblastoma patients using normal tissue complication probability (NTCP) formalism between photon (three-dimensional conformal radiotherapy, intensity-modulated radiotherapy [IMRT], volumetric-modulated arc therapy [VMAT], and HT) and proton CSI.
The treatment data of eight pediatric patients who typically received CSI treatment were used in this study. The patients were 7 years of age on average, with ages ranging from 3 to 11 years. A prescription dose of 3600 cGy was delivered in 20 fractions by the established planning methods. The Niemierko's and Lyman-Kutcher-Burman models were followed to carefully estimate NTCP and compare different treatment plans.
