Robust Angle Selection in Particle Therapy

The popularity of particle radiotherapy has grown exponentially over recent years owing to the marked advantage of the depth–dose curve and its unique biological property. However, particle therapy is sensitive to changes in anatomical structure, and the dose distribution may deteriorate. In particle therapy, robust beam angle selection plays a crucial role in mitigating inter- and intrafractional variation, including daily patient setup uncertainties and tumor motion. With the development of a rotating gantry, angle optimization has gained increasing attention. Currently, several studies use the variation in the water equivalent thickness to quantify anatomical changes during treatment. This method seems helpful in determining better beam angles and improving the robustness of planning. Therefore, this review will discuss and summarize the robust beam angles at different tumor sites in particle radiotherapy.

Transportation container for pre-processing cytogenetic assays in radiation accidents

We report a shipping container that enables a disruptive logistics for cytogenetic biodosimetry for radiation countermeasures through pre-processing cell culture during transportation. The container showed precise temperature control (< 0.01 °C) with uniform sample temperature (< 0.1 °C) to meet the biodosimetry assay requirements. Using an existing insulated shipping box and long shelf life alkaline batteries makes it ideal for national stockpile. Dose curve of cytogenetic biodosimetry assay using the shipping container showed clear dose response and high linear correlation with the control dose curve using a laboratory incubator (Pearson’s correlation coefficient: 0.992). The container’s ability of pre-processing biological samples during transportation could have a significant impact on radiation countermeasure, as well as potential impacts in other applications such as biobanking, novel molecular or cell-based assays or therapies.

In-Vitro Effects of Active Vitamin-D3 and Vitamin-A on Human Melanoma (BLM and1205Lu) Cell Growth

Though UV ray in the Sun light is essential for vitamin-D3 formation, yet UV rays can lead to skin cancer. Lack of vitamin-D3 also can lead to cancer. Hence, we decided to study the effect of vitamin-D3 on human melanoma cell models. Our aims were to study the in-vitro effects of vitamin-D3 and vitamin-A on human melanoma (BLM, 1205Lu) cell growth, as vitamins D3 and A are important for a healthy skin. Initially dose-curve (100 nM to 100 μM concentration) study was carried out with vitamin-D3 and vitamin-A (retinoic acid) on BLM cells to determine the optimal concentrations of vitamins-D3 and A for co-incubation with progesterone (50 μM) and RU-486 (50 μM). Supernatants from the treated cells were subjected to Elisarray. Vitamin-D3 and vitamin-A showed a dose-dependent decrease in cell growth. Based on the dose-curve, it was decided to use 25 μM (at 57% cell growth) of vitamin-D3 and 50 μM (at 55% cell growth) of vitamin-A for co-incubation studies. Co-incubation of vitamin-D3 with vitamin-A showed an additive effect on the decrease of BLM cell growth (20%). Similarly co-incubation of vitamin-D3 with progesterone (33% cell growth) and with RU-486 (28% cell growth) as well as co-incubation of vitamin-A with progesterone (31% cell growth) and RU-486 (18% cell growth) showed an additive effect on the decrease of BLM cell growth. Based on the BLM co-incubation studies, we decided to repeat the studies on 1205Lu cells. So, 25 μM (at 34% cell growth) of vitamin-D3 and 50 μM (at 44% cell growth) of vitamin-A were used for co-incubation studies. Co-incubation of vitamin-D3 with vitamin-A showed an additive effect on the decrease of cell growth (22%). Though co-incubation of vitamin-D3 with progesterone did not show any difference in cell growth (51%), yet co-incubation with RU-486 showed a decrease in 1205Lu cell growth (21%). Similarly co-incubation of vitamin-A with progesterone (25% cell growth) and with RU-486 (23% cell growth) showed a synergistic effect on the decrease of 1205Lu cell growth. Conclusion: These studies suggested that combination of vitamins and steroids might be effective in decreasing melanoma cell growth. Hence, various combination of vitamins and steroids will be tested for their effect on melanoma cell growth in vitro in order to develop a combo drug treatment for melanoma.

A Maximum Dose Bioassay to Assess Efficacy of Key Insecticides Against Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae)

The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornamental production. In 2019, a maximum dose bioassay was administered to 20 field populations of B. tabaci MEAM1 collected from various economic and weed hosts across south Florida to assess insecticide efficacy. The maximum dose bioassay tests the top labeled rate of the insecticide against B. tabaci adults on treated cotton leaves in a Petri dish over a 72-h period. A susceptible laboratory colony of B. tabaci MEAM1 and a colony of B. tabaci MED were also tested. Survival over 72 h was used to produce an area under the maximum dose curve, which was used to compare insecticide effects on different populations. Overall, imidacloprid demonstrated the poorest efficacy, dinotefuran and flupyradifurone were the most effective, and bifenthrin, cyantraniliprole, and thiamethoxam tended to group together, providing intermediate control. Across populations tested, survival in whitefly adults treated with dinotefuran was 50% lower than whiteflies treated with imidacloprid, about 33% lower than whiteflies treated with thiamethoxam, bifenthrin, and cyantraniliprole, and 10% lower than whiteflies treated with flupyradifurone. Efficacy of bifenthrin was less than imidacloprid on some populations, particularly from the Homestead area. Imidacloprid and thiamethoxam had no effect on mortality of the MED population when it was tested after 22 mo in culture without exposure to insecticides, although 7 mo later, these materials resulted in some mortality for the MED population.

Physical Insights from Frumkin Isotherm Applied to Electrolyte Gated Organic Transistor as Protein Biosensors

Label free biosensors based on electrolyte gated organic transistors (EGOTs) are ultra-sensitive and versatile sensing devices. The dose curve represents the change of the sensor signal as a function of...

ANALYSIS OF THE USE OF CONSTRUCTION WASTE AS SOIL ACIDITY CORRECTIVE

The construction and demolition waste (CDW) can be used as soil acidity corrective, which allow its final destination as an input of agricultural and environmental interest, beyond pollution control. This alternative of final destination makes possible the reduction on the amount of solid waste disposed in landfills, which will reduce the environmental impact and increase the useful life of the landfills. Therefore, the objective of this study was to evaluate the use of the construction waste to correct the pH of an acidic soil, typical of the southeastern region of Brazil. The CDWs used were collected in static buckets positioned next to building sites in Belo Horizonte, MG; sifted at less than 0.297 mm diameter and incorporated into an oxisol (red yellow latosol) collected on an exposed slope at Federal University of Minas Gerais (UFMG). Then, an incubation curve (after 21 days of incorporation of the waste to the soil) was performed varying the dose of the construction waste to the soil, aiming to obtain a pH x dose curve. Using logarithmic regression, the equation pH = 0.5454 ln(Dose) + 6.9646 was defined as ideal to describe this relationship. Thus, for the agricultural use it will be necessary a dose of 1,71 t ha-1, while, for pollution control, it will be necessary a dose of 46,28 t ha-1.

Analysis of Sensitometry in Radiographic Films using Optical Density Measurement

The sensitivity of radiographic films is an important factor to the clarity and accuracy of X-ray exposure to patients during treatment or diagnostic periods. It is therefore important to do a thorough analysis of the sensitivity of the radiographic film before and after exposure to enhance the Quality Assurance (QA) and the Quality Control (QC), of the exposure procedures. The optical densities (OD) of each film was measured, with a densitometer model MA 5336, made by GAMMEX. These values were then converted to the absorbed dose (X mGy), which is the amount of dose absorbed by each patient. The optical density versus the dose curve, followed the expected pattern, showing a good prediction from the General model, that the films employed in the exposures were of good quality and standard. Hence the optical density versus dose sensitometric curves depicts the outcome of the various films sensitivity after an exposure to the X-ray radiation through the patients.

CHARACTERISATION AND EVALUATION OF AL2O3:C-BASED OPTICALLY STIMULATED LUMINESCENT DOSEMETER SYSTEM FOR DIAGNOSTIC X-RAYS: PERSONAL AND IN VIVO DOSIMETRY

This study characterises and evaluates an Al2O3:C-based optically stimulated luminescent dosemeter (OSLD) system, commercially known as the nanoDot™ dosemeter and the InLight® microStar reader, for personal and in vivo dose measurements in diagnostic radiology. The system characteristics, such as dose linearity, reader accuracy, reproducibility, batch homogeneity, energy dependence and signal stability, were explored. The suitability of the nanoDot™ dosemeters was evaluated by measuring the depth dose curve, in vivo dose measurement and image perturbation. The nanoDot™ dosemeters were observed to produce a linear dose with ±2.8% coefficient variation. Significant batch inhomogeneity (8.3%) was observed. A slight energy dependence (±6.1%) was observed between 60 and 140 kVp. The InLight® microStar reader demonstrated good accuracy and a reproducibility of ±2%. The depth dose curve measured using nanoDot™ dosemeters showed slightly lower responses than Monte Carlo simulation results. The total uncertainty for a single dose measurement using this system was 11%, but it could be reduced to 9.2% when energy dependence correction was applied.