Brachytherapy applicators have come a long way since Danlos developed early intracavitary applicators to treat cervical cancer patients. Therefore, this review will help in the neoteric designs of intracavitary applicators. A detailed literature survey of the gynecological brachytherapy applicators from the era of preloading to conceptual intensity-modulated brachytherapy applicators has been carried out. Depending on the extent of the disease and patient anatomy, the selection of brachytherapy applicators plays a pivotal role in the treatment of cervical cancer. Furthermore, the selection of the applicators is also based on the imaging modalities to be used for applicator reconstruction and treatment planning. Dose acceleration in the target and reduction in nearby organs at risk can be optimized using an applicator having the capabilities of intensity-modulated brachytherapy. Now, three-dimensional printed applicators are used for patient-specific tailor-made treatment and they are fast replacing the old conventional applicators. Newer advancements in technology have greatly influenced the neoteric designs of intracavitary brachytherapy applicators.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Purpose: 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. Methods and Materials: 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. Results: The NTCP of VMAT plans in upper and middle thoracic volumes was relatively high compared to helical tomotherapy (HT) and pencil beam scanning (PBS) (all P < 0.05). PBS rather than IMRT and VMAT in the middle thoracic region (P < 0.06) could significantly reduce the NTCP of the heart. PBS significantly reduced NTCP of the lungs and liver (all P < 0.05). Conclusion: The NTCP and tumor control probability (TCP) model-based plan ranking along with dosimetric indices will help the clinical practitioner or medical physicists to choose the best treatment plan for each patient based on their anatomical or clinical challenges.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Purpose/Aim: 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. Materials and Methods: 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. P <0.05 was considered to denote statistical significance. Results: 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. Conclusion: 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.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Aim: A tissue-equivalent bolus of sufficient thickness is used to overcome build up effect to the chest wall region of postmastectomy radiotherapy (PMRT) patients with tangential technique till Radiation Therapy Oncology Group (RTOG) Grade 2 (dry desquamation) skin reaction is observed. The aim of this study is to optimize surface dose delivered to chest wall in three-dimensional radiotherapy using EBT3 film. Materials and Methods: Measurements were conducted with calibrated EBT3 films with thorax phantom under “open beam, Superflab gel (0.5 cm) and brass bolus conditions to check correlation against TPS planned doses. Eighty-two patients who received 50 Gy in 25# were randomly assigned to Group A (Superflab 0.5 cm gel bolus for first 15 fractions followed by no bolus in remaining 10 fractions), Group B or Group C (Superflab 0.5 cm gel or single layer brass bolus, respectively, till reaching RTOG Grade 2 skin toxicity). Results: Phantom measured and TPS calculated surface doses were within − 5.5%, 4.7%, and 8.6% under open beam, 0.5 cm gel, and single layer of brass bolus applications, respectively. The overall surface doses (OSD) were 80.1% ±2.9% (n = 28), 92.6% ±4.6% (n = 28), and 87.4% ±4.7% (n = 26) in Group A, B, and C, respectively. At the end of treatment, 7 out of 28; 13 out of 28; and 9 out of 26 patients developed Grade 2 skin toxicity having the OSD value of 83.0% ±1.6% (n = 7); 93.7% ±3.2% (n = 13); and 89.9% ±5.6% (n = 9) in Groups A, B, and C, respectively. At the 20^th–23^rd fraction, 2 out of 7; 6 out of 13; and 4 out of 9 patients in Groups A, B, and C developed a Grade 2 skin toxicity, while the remaining patients in each group developed at the end of treatment. Conclusions: Our objective to estimate the occurrence of optimal dose limit for bolus applications in PMRT could be achieved using clinical EBT3 film dosimetry. This study ensured correct dose to scar area to protect cosmetic effects. This may also serve as quality assurance on optimal dose delivery for expected local control in these patients.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Purpose: 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. Materials and Methods: 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. Results: 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. Conclusions: 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.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Purpose: To create and to validate knowledge-based volumetric modulated arc therapy (VMAT) models for breast cancer treatments without lymph node irradiation. Materials and Methods: One hundred VMAT-based breast plans (manual plans [MP]) were selected to create two knowledge-based VMAT models (breast left and breast right) using RapidPlan™. The plans were generated on Eclipse v15.5 (Varian Medical Systems, Palo Alto, CA) with 6 MV of a Novalis Tx equipped with a high-resolution multileaf collimator. The models were verified based on goodness-of-fit statistics using the coefficients of determination (R²) and Chi-square (χ²), and the goodness-of-estimation statistics through the mean square error (MSE). Geometrical and dosimetrical constraints were identified and removed from the RP models using statistical evaluation metrics and plots. For validation, 20 plans that integrate the models and 20 plans that do not were reoptimized with RP (closed and opened validation). Dosimetrical parameters of interest were used to compare MP versus RP plans for the Heart, Homolateral_Lung, Contralateral_Lung, and Contralateral_Breast. Optimization planning time and user independency were also analyzed. Results: The most unfavorable results of R² in both models for the organs at risk were as follows: for Contralateral_Lung 0.51 in RP right breast (RP_RB) and for Heart 0.60 in RP left breast (RP_LB). The most unfavorable results of χ² test were: for Contralateral_Breast 1.02 in RP_RB and for Heart 1.03 in RP_LB. These goodness-of-fit results show that no overfitting occurred in either of the models. There were no unfavorable results of mean square error (MSE, all < 0.05) in any of the two models. These goodness-of-estimation results show that the models have good estimation power. For closed validation, significant differences were found in RP_RB for Homolateral_Lung (all P ≤ 0.001), and in the RP_LB differences were found for the heart (all P ≤ 0.04) and for Homolateral_Lung (all P ≤ 0.022). For open validation, no statistically significant differences were obtained in either of the models. RP models had little impact on reducing optimization planning times for expert planners; nevertheless, the result showed a 30% reduction time for beginner planners. The use of RP models generates high-quality plans, without differences from the planner experience. Conclusion: Two RP models for breast cancer treatment using VMAT were successfully implemented. The use of RP models for breast cancer reduces the optimization planning time and improves the efficiency of the treatment planning process while ensuring high-quality plans.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Context: 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. Aims: The aim is to present the unlike information onto a single image as each modality of medical image contains the unalike domain of information. Settings and Design: 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. Subjects and Methods: 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. Statistical Analysis Used: 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. Results: 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. Conclusions: Experiments conclude that conventional, objective, visual evaluation shows best results for Cases 1, 3, 4, and 5.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

“Near-death experiences (NDEs)” are usually depicted with a vivid perception of departure from the physical body and being in a distinctive spatial and temporal area setting. There are challenges to whether consciousness during this phenomenon is cerebral or extracerebral? To investigate this subject further, the AWARE research projects were designed. It was a research milestone in this field. During the AWARE projects, images were put in the cardio pulmonary resuscitation (CPR) area. The person with experience of leaving the body was then asked about the nature of the images. In a recent project, a complementary system was designed that contains two main parts: a transmitter connected to the electroshock (as starter) and a receiver connected to the monitor. The laboratory experiment showed that the connection between the parts of the system was systematically and meticulously organized. This new system, such as the AWARE projects, is based on the perception of the visual and auditory elements, during the out-of-body experience component of the NDE but, unlike the AWAREs, it has three main differences in testing of visual elements: unfixed/dynamic images, “timed” movie's capacity, and the automatic activation. Also this system, records the ambient sounds.So, after the successful resuscitation, researchers will be asked about the ambient sounds specification. The new system records the ambient sounds. Consequently, it becomes feasible to study environmental and corporeal events in more detail, during the phenomenon.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background: 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. Materials and Methods: 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. Results: Analysis of picket fence tests revealed a dependence of the error upon the gantry angle. 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. Conclusions: 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.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Aim: 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. Materials and Methods: 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. Results: The maximum individual error obtained (DR of 35 MU/min, SP of 2.0 cm/s) was 1.96 ± 0.1 mm. Only 4.4% of MLCs showed ≥ ±1 mm positional error. When the treatment delivery is interrupted multiple times in VMAT delivery, the influence of interruption in MLC-PE overwhelmed the influence by DR and SP. For a sub-group analysis of independent and dependent variables, the mean MLC-PE was 0.18 ± 0.4 mm 0.19 ± 0.42 mm, respectively. Conclusion: Determination of MLC-PEs using a mathematical function without approximation indicates that MLC-PE is not a function of MLC speed. In less than 5% of the studied scenarios, the MLC-PE exceeds its tolerance value (±1 mm). The MLC-PE is significantly less in modern machines due to advancements in the delivery mechanism.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Purpose: 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]). Materials and Methods: 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. Results: 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. Conclusions: 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 the fingerprint region occurred at 24 and 48 h of EMF exposure. That means it was during the first 48 h after EMF exposure a great number of dynamic changes occurred. However, in the case of AT-MSCs in 72 h EMF and 72 h control, no significant differences were noted in the FTIR spectra, which means that the chemical composition in these two cases is similar. EMF is not neutral for stem cells, especially in the in the first hours of interaction (24 h, 48 h).

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Introduction: The accuracy of dose calculation algorithms depends on the electron density and computed tomography (CT) number of medium scanned. Our study aimed to verify the impact of different CT scanning protocols on Hounsfield unit (HU) and effect on dose calculation algorithms. Materials and Methods: CIRS thorax phantom with different density material plugs was scanned at varying tube voltages from CT scanner and HU values were measured in treatment planning system (TPS). Calibration curves of electron density at different tube voltages were plotted and used for dose calculation with different calculation algorithms at varying high energy megavoltage photon energies. Results: Insignificant difference is obtained in electron density curves plotted at different tube voltages. The mean variation in HU values was found at different tube voltages for bone, lung, and water are 896.75 (standard deviation [SD] 122.88), −799.25 (SD 5.74), and −17.5 (SD 0.57), respectively. The estimated P values for change in HU values were 0.089, 0.258, and 0.121 for bone, lung, and water, respectively. Pencil beam (PB) convolution and collapsed cone algorithms show no significant dose difference, i.e., <1% variation and Monte Carlo (MC) shows maximum dose difference up to 1.4%. Conclusion: Third-generation algorithms such as MC shows dependence on varying tube voltages in dose calculation. Calibration curves plotted at different kVp in TPS advised to be chosen wisely to avoid any dosimetric errors in different medium.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Backgorund: 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. Materials and Methods: 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. Results: 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. Conclusion: The results reveal that PEG coated nanoparticle might be a potential candidate to work as radiotherapy sensitizer in colorectal cancer.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

This study investigates whether patient safety can be enhanced by the implementation of an automated electronic checklist (PlanCheck) for physics quality control review (QCR) of radiotherapy photon plans. PlanCheck evaluates both technical aspects and DVH constraints. Three hundred and thirty-one consecutively approved radiotherapy plans previously reviewed with manual QCR were retrospectively checked with PlanCheck. Four hundred and thirty-three (3.4%) of the 12783 automated technical checks executed in the 331 plans yielded an error. All errors were scored using the severity rating from the American Association of Physicists in Medicine TG-100 report. Nineteen of these errors (4%) either could have affected or affected target dose (severity 5+) implicating a maximum dose difference to the target or a critical organ at risk of 0.5% to 10% and 3 errors could have resulted in stereotactic brain treatments being delivered to the wrong location (severity 10). Forty-seven breast cancer plans were retrospectively subjected to automated DVH check, 10 undocumented dose constraint violations were found. PlanCheck has been shown to reduce errors in manually reviewed radiotherapy plans and thus to enhance patient safety.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

[FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]