Average D2 Research Articles

SP5.11 - The Impact of Total Pelvic Exenteration on Surgeon Fatigue: Is it time we monitor our surgeons?

Abstract Aims Total pelvic exenteration surgery (TPE) is a radical procedure requiring significant surgeon mental and physical stamina. Literature surrounding surgeon fatigue remains minimal. This study investigated impact of performing high complexity TPE on surgeon fatigue. Methods Two surgeons ([#1]/[#2]) delivering high complexity TPEs between 1st November 2022 – 1st September 2023 in a tertiary centre (110/annum) were assessed using a predefined protocol. Surgeon heart rate, concentration performance (d2 Brickencamp test) and Surgery Task Load Index (SURG-TLX) were measured across intraoperative stages (mobilisation, dissection, reconstruction). Surgeons underwent baseline cardiopulmonary exercise testing. Results All-cause mortality rate was 0% at median follow up of 3 (1-11) months. Baseline VO2 max and anaerobic thresholds: #1 = 37.6 mL/kg/min, 50% and #2 = 54.3 mL/kg/min, 70%. Mean error rate (ER): d2 test 1 and 2: #1 = 3.58% [0.91%–8.60%] [SD = 3.16, 95% CI = 0.27 to 6.91], #2 = 4.46% [1.37%–7.23%] [SD = 2.55, 95% CI = 1.79 to 7.14]. Greater HR deviation correlated with higher test 2 ER for both subjects (p>0.05). During dissection, mean HR increased from baseline: mean of 70% [#1] and 51.9% [#2]; max HR 106.7% [#1] and 111.5% [#2]. Subjects demonstrated smaller mean HR increase from baseline during dissection operating together versus with junior trainees (#1 = 46.7% [p< 0.001] and #2 = 48.1% [p>0.05]). SURG-TLX situational stress domain was most impacted. Conclusions Surgeon HR fluctuations corresponded with significant intraoperative events. Assistant dependent HR fluctuation and increased average d2 ER was demonstrated by greater HR deviations during dissection. Further investigation optimising strategies minimising surgeon fatigue is required.

HIGH DOSE RATE BRACHYTHERAPY IN THE TREATMENT OF OPERATED ENDOMETRIAL CANCERS: ABOUT 60 CASES

Introduction:Endometrial cancer is the third gyneco-mammary cancer in the radiotherapy-brachytherapy department of the RABAT national oncology institute.Brachytherapy has an important place in the therapeutic strategy. The objective of the study:Is to analyze the coverage of target volumes as well as the dose to organs at risk with three-dimensional dosimetric planning and toxicity assessment. Material and methods:This is a retrospective study of 60 cases of operated endometrial cancers treated by high dose rate brachytherapy without external radiotherapy or chemotherapy collected in the radiotherapy department of the National Institute of Oncology RABAT between January 2018 and December 2020. A dosimetric scan without injection was performed at the first session and was used to delineate the clinical anatomic target volume (CTV). We evaluated the D100 of the clinical target volume and the D2 cm3 of the bladder, rectum and small intestine. We also analyzed acute genitourinary and gastrointestinal toxicity. Results:The average age of the patients was 49 years. Endometrioid carcinoma accounted for 98.5%, with one case of mucinous carcinoma. All patients underwent surgery.The brachytherapy protocol used was 3 × 7 Gy (75%) or 4 × 5.5 Gy (17%) in weekly sessions A single patient received a reduced total dose of 19.8 Gy in 3 fractions of 5.5 Gy due to a high rectal dose.The average target volume coverage (D100) was 96.50%.The average D2 cm3 per session received by the bladder, rectum and small intestine were 4.06 Gy, 4.9 Gy and 2.8 Gy, respectively.Regarding genitourinary toxicity, we noted two grade 1 cystitis, one grade 2, two grade 1 mucositis and one grade 2.For gastrointestinal toxicity, no cases of grade greater than 1 were noted.No grade 3 or 4 toxicities were recorded. Conclusion:High dose rate brachytherapy has an important place in the therapeutic strategy for endometrial cancer.The very low toxicity recalls the good tolerance of this treatment whichapplies to the entire population.

Analysis of genetic diversity in groundnut (Arachis Hypogaea L.)

The genetic diversity among 105 groundnut germplasm for 11 characters was measured by employing D2 statistic and these were grouped into 15 clusters. The average D2 values of inter cluster distances, showed maximum distancebetween Cluster V and XV (12283.79) followed by inter cluster distance (11278.47) between III and XV. The clusters were ranked based on the overall score across 11 traits. Accordingly, cluster X was superior which indicates the presence of most promising genotypes in them. Hundred pod weight and harvest index had maximum contribution of 43.64% and 21.76% respectively to the divergence of genotypes.

The Feasibility of Dose-Escalated Radiation Therapy for Glioblastoma Using Biological Image Guided Adaptive Radiotherapy (BIGART)

Radiotherapy dose escalation (DE) for glioblastoma (GBM) has been an area of active research. We aimed to study the imaging changes within residual gross tumor volumes (GTV) through the course of concurrent chemo-radiotherapy (CCRT) using multiparametric magnetic resonance imaging (mpMRI). Diffusion, perfusion and chemical exchange saturation transfer (CEST) characteristics of the tumor and its microenvironment were investigated to identify a GTV subvolume potentially associated with radio resistance. We used biological image-guided adaptive radiotherapy (BIGART) to study the feasibility of DE to this GTV subvolume using either photon or proton beam therapy (PBT). We prospectively identified GBM patients with >5cc residual tumor post-resection who were candidates for radical CCRT (60 Gy in 30 daily fractions over 6-weeks with concurrent temozolomide 75mg/m2 daily). We observed the imaging changes with serial mpMRI scans done at baseline, after 2, 4 and 6-weeks of CCRT. Regions of interest (ROIs) within the GTV associated with the following abnormal values at week 2 were identified: apparent diffusion coefficient (ADC): 750-1000 ×10-6 mm2/s; relative cerebral blood volume (rCBV): 1.75-6; and APT-w CEST signal intensity >1.79%. The overlap regions of these ROIs were defined as a novel biological target volume (BTV), identifying the potential area of maximal radioresistance. An in silico study was performed using a technology company's treatment planning system to evaluate the feasibility of planning adaptive treatment to the BTV to total dose of 75 Gy in 30 fractions. This is given in two phases: 30 Gy/15# to the whole PTV as per standard practice, followed by a simultaneous integrated boost (SIB) of 45 Gy/15 fractions while maintaining the dose to the rest of the of the PTV to 60 Gy. Either photons or PBT were used to keep doses to organs at risk (OARs) within standard clinical tolerances. Nine patients were recruited for this analysis and a total of 27 mpMRI scans were studied. Median BTVs to GTVs ratio was 35% (range 22-47%). Volumetric-modulated arc (VMAT) photon and PBT adaptive plans for dose escalation to BTVs were created in all cases whilst maintaining OAR tolerances. Both VMAT and PBT provided acceptable target coverage with average BTV-PTV D98% of 73 Gy (range 71.5-73.8 Gy) and average D2% of 76 Gy (range 75.4-77 Gy) while effectively sparing OARs. Sharper dose gradient between DE-BTV and PTV was achieved with VMAT. PBT was particularly advantageous in minimizing the low-dose spillage outside the BTV. We hereby propose a platform for adaptive radiotherapy to GBM tumors with biological-image guidance through the utilization of mpMRI to evaluate the tumor and its microenvironment during CCRT. We identified thresholds for tumor sub volumes showing the most resistant imaging features and created precise BTVs that allowed for dose escalation. PBT represents an additional useful tool for BIGART planning that will be investigated further in our ongoing work.

Dosimetric feasibility of dose-painting radiotherapy for targeting hypoxia in prostate cancer on a novel ring gantry radiotherapy system.

73 Background: This study aimed at demonstrating the dosimetric feasibility of tumoral and hypoxia-guided dose escalated radiation therapy in prostate cancer on a novel ring gantry system TPS, based on conventionally fractionated and hypofractionated regimens. Methods: Three patients who underwent external-beam RT for intermediate-risk prostate cancer in the PAIR prostate study and had pre-therapeutic F-MISO PET uptake in the tumor, were selected. The GTV and the hypoxic region (biological tumor volume [BTV]) within the PTV on F-MISO PET uptake were delineated. IMRT planning based on three different prescriptions was performed: 1) Standard fractionation (SF)- 77Gy/35 fractions (fx) to PTV, with a boost to 95Gy and 118Gy in 35 fx to the GTV and to the hypoxic region defined by F-MISO PET, respectively, 2) moderate hypofractionation (MH)- 60 Gy/20 fx with a boost to 67Gy and 91Gy in 20 fx to the GTV and to the hypoxic region, respectively, and 3) high hypofractionation (HH)- 40 Gy/5 fx with a boost to 50Gy in 5 fx to the GTV and as high as possible to the hypoxic region (SBRT). Planning was performed on the research version of the RefleXion treatment planning system (X1-TPS). Results: The average size of the GTV and BTV was 6.03±2.05 cc, and 1.90±1.64 cc, respectively. For the SF regimen, the average D98% and D2% to the PTV, GTV and BTV were 71.33±0.15 Gy and 110.43±8.57 Gy; 91.43±1.12 Gy and 108.53± 10.29 Gy; and 112.33±3.54 Gy, and 121.37±1.31 Gy, respectively. For the MH and HH techniques, the average D98% to the PTV was 56.13±0.51 Gy, and 37.03± 1.81 Gy, and the average D2% was 85.53±8.52 Gy, and 58.47±1.90 Gy. In addition, the average D98%, and D2% to the GTV was 65.67±0.15 Gy, and 80.27±10.20 Gy using the MH treatment technique, while the average D98%, and D2% to the BTV was 85.87±5.00 Gy, and 94.9±1.15 Gy, respectively. Also, for the HH treatment planning method, the average D98%, and D2% to the GTV was 50.33±3.79 Gy, and 57.23±4.75 Gy, while the average D98%, and D2% to the BTV was 54.57±3.67 Gy and 61.00±2.17 Gy, respectively. The average D50% of Bladder, Rectum, and Femoral heads was 12.28±11.39 Gy, 26.09±5.89 Gy, and 11.44±2.92 Gy, while the average V15Gy was 43.07±18.68%, 72.39±8.81 %, and 23.43±20.44%, respectively. Conclusions: This study showed the dosimetric feasibility of dose-escalating the tumor and the hypoxic region in patients with prostate cancer on the RefleXion X1 TPS without compromising the OARs dose limits.

The Effect of Volume Target on Quality of Radiotherapy using 3DCRT and IMRT: Dosimetry and Radiobiological Evaluation

<span>The main goal of radiotherapy is to deliver the maximum possible dose to the target volume and the minimum possible to the surrounding healthy tissue. In this study, planning was carried out on the TPS Eclipse Varian Medical System using 3DCRT and IMRT techniques for 14 cancer patients. 6 cases of lung cancer with PTV were in the range of 175.1 cc - 875.5 cc, and eight brain cancer patients with a PTV range of 148.5 cc - 841.2 cc. This study aims to determine the effect of target volume on the quality of radiation therapy planning using the 3DCRT and IMRT techniques. The evaluation was carried out using dosimetry and radiobiology analysis. Dosimetry assessment analyzes the average dose, D98, D50, D2, CI, and HI on PTV and the average dose on OAR. Radiobiological evaluation by calculating the value of TCP, NTCP, and UTCP. The results showed that based on dosimetry and radiobiology evaluation, the IMRT technique provides better planning quality for radiation therapy by increasing the probability of cancer cells dying at PTV and reducing the risk of OAR compared to planning using the 3DCRT technique. The effect of PTV on planning quality using statistical regression tests showed that PTV did not significantly impact the quality of radiation therapy planning results either using the 3DCRT technique or the IMRT technique.</span>

Dosimetric comparison of pencil beam scanning proton therapy with or without multi-leaf collimator versus volumetric-modulated arc therapy for treatment of malignant glioma.

This study aimed to examine the dosimetric effect of intensity-modulated proton therapy (IMPT) with a multi-leaf collimator (MLC) in treating malignant glioma. We compared the dose distribution of IMPT with or without MLC (IMPTMLC+ or IMPTMLC-, respectively) using pencil beam scanning and volumetric-modulated arc therapy (VMAT) in simultaneous integrated boost (SIB) plans for 16 patients with malignant gliomas. High- and low-risk target volumes were assessed using D2%, V90%, V95%, homogeneity index (HI), and conformity index (CI). Organs at risk (OARs) were evaluated using the average dose (Dmean) and D2%. Furthermore, the dose to the normal brain was evaluated using from V5Gy to V40Gy at 5 Gy intervals. There were no significant differences among all techniques regarding V90%, V95%, and CI for the targets. HI and D2% for IMPTMLC+ and IMPTMLC- were significantly superior to those for VMAT (p < 0.01). The Dmean and D2% of all OARs for IMPTMLC+ were equivalent or superior to those of other techniques. Regarding the normal brain, there was no significant difference in V40Gy among all techniques whereas V5Gy to V35Gy in IMPTMLC+ were significantly smaller than those in IMPTMLC- (with differences ranging from 0.45% to 4.80%, p < 0.05) and VMAT (with differences ranging from 6.85% to 57.94%, p < 0.01). IMPTMLC+ could reduce the dose to OARs, while maintaining target coverage compared to IMPTMLC- and VMAT in treating malignant glioma.

An Analysis of the Impact of Groundwater Overdraft on Runoff Generation in the North China Plain with a Hydrological Modeling Framework

The long-term overexploitation of groundwater has caused sharp decreases in groundwater table depth and water storage in the agricultural areas of the North China Plain, which has led to obvious changes in the runoff process of the hydrological cycle, affecting the mechanism of runoff generation. Evaluating the impact of groundwater overdraft on runoff generation using hydrological models is the focus of the current work. Herein, a hydrological modeling framework is proposed based on the Variable Infiltration Capacity (VIC) model. The optimal parameters of the VIC model were determined by the synergetic calibration method, combining runoff, evaporation, and water storage levels. Meanwhile, a sliding calibration scheme was employed to explore the implied relationships among runoff coefficient, groundwater exploitation, and model parameters, particularly for the thickness of the second soil layer (i.e., parameter d2), both for the whole period and the sliding window periods. Overall, the VIC model showed good applicability in the southern Haihe river plain, as demonstrated by the low absolute value of the relative error (RE) between the simulated and observed data for runoff and evaporation, with all REs &lt; 8%, as well as large correlation coefficients (CC, all &gt; 0.8). In addition, the CCs between the simulated and the observed data for water storage were all above 0.7. The calibrated optimal parameter d2 increased as the sliding window period increased, and the average d2 gradually increased from 0.372 m to 0.415 m, for which we also found high correlations with both the groundwater table and water storage levels. Additionally, increases in the parameter d2 led to decreases in the runoff coefficient. From 2003 to 2016, the parameter d2 increased from 0.36 m to 0.42 m, and the runoff coefficient decreased by about 0.02.

Genetic Divergence Analysis of Dahlia (Dahlia variabilis L.) Genotypes

The present investigation was carried out to assess the extent of genetic variability, heritability, genetic advance and genetic divergence using 35 dahlia (Dahlia variabilis L.) genotypes with 20 characters. Moderate to high GCV and PCV were recorded for almost all the characters under study emphasizing the existence of variation in the population. All the characters (except plant spread and width of the tuber) showed high heritability along with higher or moderate genotypic coefficient of variation and genetic advance indicating that most likely the heritability was due to additive gene effects and the genotypes under study were highly diverse. The inter-cluster average D2 value was maximum between the cluster V and III (D2=6704.46) and minimum inter cluster distance was obtained between cluster IV and I (D2 =1256.64).

Fast robust optimization of proton PBS arc therapy plans using early energy layer selection and spot assignment

Objective. Proton pencil-beam scanning arcs (PBS arcs) have gained much attention during the past years, due to its potential for increased clinical benefit compared to conventional proton therapy. Previous studies on PBS arcs have primarily been focused on plan quality, and lately efforts have been made to reduce the delivery time. However, the methods presented so far suffer from slow optimization processes. Approach. We present a new method for fast robust optimization of PBS arc plans. The new method assigns a single energy layer per discretized direction prior to spot weight optimization and reduces the number of initial spots considerably compared to conventional methods. We used the new method for three prostate cancer patients with a prescribed dose to the CTV of 77 GyRBE in 35 fractions. For each of the patients, four plans were created: 2-beam IMPT (2IMPT), 1-beam PBS arc (1Arc), 1-beam PBS arc without focus on reducing upward energy jumps (1Arc_unseq) and two-beam PBS arc (2Arc). Main results. All PBS arc plans show a reduced integral dose compared to their respective 2IMPT plans. In the nominal case, the average CTV D98 and D2 metrics over the three patients were best for the 2Arc, followed by 2IMPT (/ 7523/7986 cGyRBE (2IMPT), 7478/7984 cGy (1Arc), 7486/7951 cGy (1Arc_unseq), 7531/7951 cGyRBE (2Arc)). The average robust target coverage in terms of V95 of the voxelwise minimum dose distribution (evaluated over 42 scenarios) was: 98.0% (2IMPT), 88.6% (1Arc), 92.5% (1Arc_unseq), 97.3% (2Arc). The optimization time, including spot selection and spot dose computation, is longest for the 2Arc plan, but is below 6 min for all patients. The maximum estimated delivery time for all types of arc plans is just above 5 min Significance. The ability for efficient treatment planning constitutes an important step towards clinical introduction of proton PBS arcs.

Genetic diversity analysis of Pearl Millet germplasm by cluster analysis

There are 40 genotypes of pearl millet that were gathered from ICRISAT in Hyderabad for the study. The experiment was performed in triplicate using Randomized Block Design. With an average D2 value of 398.08, the experimental material was divided into seven clusters, indicating the presence of diversity across the lines for the attributes being studied. Among different clusters the maximum cluster lines i.e., ten lines were observed in cluster V followed by cluster IV, cluster III, cluster I, cluster II, cluster VII, and cluster VI. Cluster V has the greatest intra cluster distance, followed by Cluster II, Cluster IV, and Cluster I. As a result, within these clusters, selection might be based on the greatest mean for desirable characteristics. The relative divergence shows the degree to which each cluster differs. The highest order of divergence was observed in cluster VIII and cluster X, followed by cluster V and cluster VIII. The results revealed that the parents are genetically heterogeneous in these clusters. The high heterotic response may have been achieved when used in a hybridization programme. Cluster VI and Cluster VII had the shortest inter-cluster distance, indicating low genetic diversity. Plant height had the highest cluster value in cluster VIII and the lowest in cluster X, whereas phenological parameters like days to flowering and days to maturity had the highest cluster value in cluster II. Days to flowering were the most important factor in genetic divergence, followed by the number of panicle length, fodder yield per plot, and productive tillers per plant.

Antitumor Activities of Biosynthesized Silver Nanoparticles using Dodonaea viscosa (L.) Leaves Extract

Biosynthesis of silver nanoparticles (AgNPs) from plant extracts is considered one of the green chemistry methods, as this method is characterized by ease, fast and low cost to manipulate. Interestingly, AgNPs have an important role, especially in nano-medicine. Using AgNPs for cancer therapy are an affordable way to control tumor growth and constitute a choice strategy to fight cancer cells. First type of conventional cancer treatment is surgical treatment then radiation and chemotherapy. However, these treatments may work for some cancer subtypes, and have various side effects, in most cases, with high doses. In this study, silver nanoparticles (AgNPs) were biosynthesized using Dodonaea viscosa leaves extract. The formation of these particles was confirmed through the color change, UV-Visible Spectrophotometer displaying at 463nm.While the particles characterization was done by Surface Plasmon Resonance (SPR) band and Fourier Transform Infra-Red (FT-IR) spectroscopy which revealed the effective functional groups that have ability to bio-reduction silver ion Ag+. In addition, X-ray diffraction (XRD) determined the crystal structure of silver nanoparticles, as shown by the peaks at 2θ values of 38.1874, 46.2491, 57.5409 and76. 8313ο.The atomic force microscopy (AFM) analysis showed the size and the surface properties of biosynthesized nanoparticles, and the silver nanoparticles had an average size of 60.22 nm. Finally, scanning electron microscopy (SEM) showed spherical shape of AgNPs and having different average diameter D1 (21.10), D2 (21.39) and D3 (11.86) nm. In vitro, the synthesized AgNPs exhibited potential anti-tumor activities against human lung cancer (A549) and ovarian cancer (SK-OV-3) carcinoma cell lines in a dose-dependent manner with IC50 of 1.73 and 2.23µg.ml-1, respectively. Our results showed the promising use of AgNPs as an alternative treatment for cancer cells directly and selectively on A549 cell line at concentrations (2.000, 1.699, 1.398 and 1.301 μg /mL).

Selection criteria for high-dose-rate surface brachytherapy and electron beam therapy in cutaneous oncology

PurposeHigh-dose-rate (HDR) brachytherapy is an alternative treatment to electron external beam radiation therapy (EBRT) of superficial skin lesions. The purpose of this study was to establish the selection criteria for HDR brachytherapy technique (HDR-BT) and EBRT in cutaneous oncology for various clinical scenarios.Material and methodsThe study consists of two parts: a) EBRT and HDR-BT treatment plans comparison analyzing clinical target volumes (CTVs) with different geometries, field sizes, and topologies, and b) development of a prediction model capable of characterization of dose distributions in HDR surface brachytherapy for various geometries of treatment sites.ResultsA loss of CTV coverage for the electron plans (D90, D95) was recorded up to 45%, when curvature of the applicator increased over 30°. Values for D2 cm3 for both plans were comparable, and they were in range of ±8% of prescription dose. An increase in higher doses (D0.5 cm3 and D0.1 cm3) was observed in HDR-BT plans, and it was greater for larger lesions. The average increase was 3.8% for D0.5 cm3 and 12.3% for D0.1 cm3. When CTV was approximately flat, electron plans were comparable with HDR-BT plans, having lower average D2 cm3, D0.5 cm3, and D0.1 cm3 of 7.7%. Degradation of quality of electron plans was found to be more dependent on target curvature than on CTV size.ConclusionsBoth EBRT and HDR-BT could be used in treatments of superficial lesions. HDR-BT revealed superior CTV coverage when the surface was very large, complex, curvy, or rounded, and when the topology was complicated. The prediction model can be used for an approximate calculation and quick assessment of radiation dose to organs-at-risk (OARs), at a depth or at a lateral distance from CTV.

Dosimetry and Feasibility Studies of Volumetric Modulated Arc Therapy With Deep Inspiration Breath-Hold Using Optical Surface Management System for Left-Sided Breast Cancer Patients.

BackgroundDuring radiotherapy (RT) procedure of breast cancer, portions of the heart and lung will receive some radiation dose, which may result in acute and late toxicities. In the current study, we report the experience of our single institution with organs at risk (OARs)–sparing RT with deep inspiration breath hold (DIBH) using an Optical Surface Management System (OSMS) and compare the dosimetric parameters with that of free breathing (FB).Patients and MethodsForty-eight cases diagnosed as early stage left-sided breast cancer scheduled for postoperative RT were enrolled. The OSMS was used to monitor the breathing magnitude and track the real-time respiratory status, which can control a stable lung and heart volume during RT delivery under DIBH. We did the dosimetric analysis of the heart, left anterior descending (LAD) coronary artery, lungs, and contralateral breast under FB and DIBH plans.ResultsCompared with FB–volumetric-modulated arc therapy (FB-VMAT), DIBH-VMAT resulted in significantly changed volumes to the heart and lungs receiving irradiation dose. The average mean heart dose and average D2%, V5, and V10 showed significant differences between the DIBH and FB techniques. For the LAD coronary artery, we found significantly reduced average mean dose, D2%, and V10 with DIBH. Similar results were also found in the lungs and contralateral breast. The use of flattening-filter–free decreased treatment time compared with the flat beam mode in our VMAT (p < 0.05). For the 48 patients, there were no significant differences in the lateral, longitudinal, and vertical directions between OSMS and cone beam CT.ConclusionsDIBH-VMAT with OSMS is very feasible in daily practice with excellent patient compliance in our single-center experience. Note that OSMS is an effective tool that may allow easier-to-achieve precise positioning and better and shorter position-verify time. Meanwhile, compared with FB, DIBH was characterized by lower doses to OARs, which may reduce the probability of cardiac and pulmonary complications in the future.

An institutional review: dosimetry comparison between simultaneous integrated boost IMRT and VMAT for prostate cancer

AbstractPurpose:A comparative study was performed about the plan parameters and quality indices between volumetric arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for the treatment of high-risk prostate cancer patients. The aim of this retrospective study was to compare the two methods of external beam radiotherapy IMRT and VMAT in terms of plan quality and efficacy.Material and method:Fifteen high-risk prostate patients were planned for radiotherapy using 6 MV photon. Three dose levels were contoured having Planning Tumour Volume 1 (PTV1 = 48 Gy), Planning Tumour Volume 2 (PTV2 = 57.6 Gy) and Planning Tumour Volume 3 (PTV3 = 60 Gy). Setup margins were given using the CHIP trial method. The prescribed PTV3 dose was 60 Gy in 20 fractions which is biologically equivalent to 74 Gy in 37 fractions using α/β = 3. In case of IMRT, seven fixed beam angles 30, 60, 105, 180, 255, 300 and 330 were used and the dose was optimised using the sliding window method. In case of rapid arc technique, one or two full arcs were used for dose optimisation while keeping all the dose constraints and other planning parameters same used in IMRT. The plan evaluation parameters and Organ at risks (OARs) doses were calculated using a dose volume histogram (DVH).Results:The average D2, D5, D95 and PTVmean for PTV3 were 61.22, 61.13, 58.12, 60.00 Gy and 62.41 62.24 59.53 61.12 Gy for IMRT and VMAT, respectively. The averages V60 for bladder and V30 for rectum were 22.81, 25 and 67, 65% for IMRT and VMAT, respectively. The average homogeneity index (HI), conformity index (CI) and gradient index (GI) were 1.04, 1.4833, 14.79 and 1.04, 1.704, 7.89 for IMRT and VMAT, respectively.Conclusion:VMAT takes less dose-delivery time and lesser number of monitoring units than IMRT, thus it compensates the intrafractional movements during dose delivery. The Dose GI in VMAT was much better than IMRT. This indicates sharper dose fall off near the normal tissue. No other major differences were observed in terms of plan evaluation parameters between IMRT and VMAT techniques. So, we conclude that VMAT technique is more efficient than IMRT in terms of plan quality and dose delivery.

Binaphthyl-Based Macrocycles as Optical Sensors for Aromatic Diphenols.

The synthesis of several rigid, homochiral organic macrocycles possessing, respectively, average molecular D2 and D3 symmetries, is described. They have been obtained from aromatic dicarboxylic acids, in combination with an axially-chiral, suitable dibenzylic alcohol, derived from 1,1′-binaphthyl-2,2′-diol (BINOL) using one-pot esterification reactions in good isolated yields. NMR and circular dichroism (CD) spectroscopies detect the structural and shape variability in the scaffolds, reflected both in terms of the changes in chemical shifts and the shape of selected proton resonances, and in terms of the variation of the CD signature related to the dihedral angle defined by the binaphthyl units embedded in the rigid cyclic skeleton. The D2 cyclic adducts are able to form stable complexes with aromatic diphenols, with binding strengths that are dependent on small variations in the spacing units, and therefore on the shapes of the internal cavities of the cyclic structures.

Harmonization of proton treatment planning for head and neck cancer using pencil beam scanning: first report of the IPACS collaboration group

Background and purpose: A collaborative network between proton therapy (PT) centres in Trento in Italy, Poland, Austria, Czech Republic and Sweden (IPACS) was founded to implement trials and harmonize PT. This is the first report of IPACS with the aim to show the level of harmonization that can be achieved for proton therapy planning of head and neck (sino-nasal) cancer.Methods: CT-data sets of five patients were included. During several face-to-face and online meetings, a common treatment planning protocol was developed. Each centre used its own treatment planning system (TPS) and planning approach with some restrictions specified in the treatment planning protocol. In addition, volumetric modulated arc therapy (VMAT) photon plans were created.Results: For CTV1, the average Dmedian was 59.3 ± 2.4 Gy(RBE) for protons and 58.8 ± 2.0 Gy(RBE) for VMAT (aim was 56 Gy(RBE)). For CTV2, the average Dmedian was 71.2 ± 1.0 Gy(RBE) for protons and 70.6 ± 0.4 Gy(RBE) for VMAT (aim was 70 Gy(RBE)). The average D2% for the spinal cord was 25.1 ± 8.5 Gy(RBE) for protons and 47.6 ± 1.4 Gy(RBE) for VMAT. The average D2% for chiasm was 46.5 ± 4.4 Gy(RBE) for protons and 50.8 ± 1.4 Gy(RBE) for VMAT, respectively. Robust evaluation was performed and showed the least robust plans for plans with a low number of beams.Discussion: In conclusion, several influences on harmonization were identified: adherence/interpretation to/of the protocol, available technology, experience in treatment planning and use of different beam arrangements. In future, all OARs that should be included in the optimization need to be specified in order to further harmonize treatment planning.

The “safe zone” for infrapectineal plate-screw fixation of quadrilateral plate fractures

Extra-articular screw placement in the true pelvis for fixing quadrilateral plate fractures remains challenging. We aimed to define the "safe zone" on the quadrilateral surface to facilitate safe plate-screw placement.Twenty cadaveric hemipelves were sectioned and assembled to define the projection of the acetabular boundary on the quadrilateral surface. Three lines (X, Y, and Z) were drawn tangent to the projection, with X parallel to the iliopectineal line, Y perpendicular to the iliopectineal line, and Z parallel to the posterior border of the ischial body. Then, the distances between X and the iliopectineal line (D1), Y and the sacroiliac joint (D2), and Z and the posterior border of the ischium (D3) could be used to determine a "safe zone" on the quadrilateral surface for screw insertion. We included 15 patients whose conditions satisfied the definition of a comminuted quadrilateral plate fracture and applied two-ended buttress plates for treatment in accordance with this "safe zone."The average D1 was 50.0 mm, the average D2 was 30.6 mm, and the average D3 was 12.4 mm. For all 15 patients with comminuted quadrilateral fracture who were treated, no intraoperative or postoperative screw penetration of the acetabulum was identified, and no loss of reduction was observed during an average follow up of 17.7 months.The "safe zone" established in this study simplifies extraarticular screw placement for managing quadrilateral plate fractures in the true pelvis. As a result, two-ended buttress plate fixation in the true pelvis becomes safe, therefore, treatment with two-ended buttress plates may represent a viable alternative to single-ended elastic fixation in the management of comminuted quadrilateral fractures.

Dosimetric evaluation of four whole brain radiation therapy approaches with hippocampus and inner ear avoidance and simultaneous integrated boost for limited brain metastases

AimsTo perform a dosimetric evaluation of four different simultaneous integrated boost whole brain radiotherapy modalities with hippocampus and inner ear avoidance in the treatment of limited brain metastases.MethodsComputed tomography/magnetic resonance imaging data of 10 patients with limited (1–5) brain metastases were used to replan step-and-shoot intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiation therapy (dIMRT), volumetric-modulated arc therapy (VMAT), and helical tomotherapy (Tomo). The prescribed doses of 40–50 Gy in 10 fractions and 30 Gy in 10 fractions were simultaneously delivered to the metastatic lesions and the whole-brain volume, respectively. The hippocampal dose met the RTOG 0933 criteria for hippocampal avoidance (Dmax ≤17 Gy, D100% ≤10 Gy). The inner ear dose was restrained to Dmean ≤15 Gy. Target coverage (TC), homogeneity index (HI), conformity index (CI), maximum dose (Dmax), minimum dose (Dmin) and dose to organs at risk (OARs) were compared.ResultsAll plans met the indicated dose restrictions. The mean percentage of planning target volume of metastases (PTVmets) coverage ranged from 97.1 to 99.4%. For planning target volume of brain (PTVbrain), Tomo provided the lowest average D2% (37.5 ± 2.8 Gy), the highest average D98% (25.2 ± 2.0 Gy), and the best TC (92.6% ± 2.1%) and CI (0.79 ± 0.06). The two fixed gantry IMRT modalities (step and shot, dynamic) provided similar PTVbrain dose homogeneity (both 0.76). Significant differences across the four approaches were observed for the maximum and minimum doses to the hippocampus and the maximum doses to the eyes, lens and optic nerves.ConclusionAll four radiotherapy modalities produced acceptable treatment plans with good avoidance of the hippocampus and inner ear. Tomo obtained satisfactory PTVbrain coverage and the best homogeneity index.Trial registrationClinicaltrials.gov, NCT03414944. Registered 29 January 2018

Genetic diversity analysis in chickpea (Cicer arietinum L.) grown under rainfed and irrigated conditions for quality and yield attributing traits

Genetic diversity among 30 chickpea genotypes was assessed for quality and yield attributing and traits at Regional Agricultural Research Station, Nandyal during rabi 2016-17 under both rainfed and irrigated conditions individually. The genotypes were grown in randomized block design (RBD) with three replications each. Genetic diversity study grouped 30 chickpea genotypes into five different clusters under both the tested environments. 100 seed weight followed by cooking time for soaked seeds contributed maximum towards diversity under rainfed as well as irrigated conditions. Inter cluster average D2 values stretched between 9.32 and 21.96 under rain fed condition, while it was comparatively lower and varied from 3.77 to 15.76 under irrigated condition. Cluster II under rainfed and cluster V under irrigated were identified to be the most divergent clusters. Under irrigated, genotype RVSSG- 37 from cluster II, NBeG-840, CSJK- 25, CSJK- 24, MNK- 1, NBeG-459 from cluster III, genotype NBeG-833 from cluster IV, KAK- 2, Vihar, ICCV- 15308 from cluster V and under irrigated condition, the genotype NBeG 831 of cluster II, RVSSG- 37, NBeG-459, CSJK- 25, NBeG-840, PKV-4 from cluster III, KAK- 2 from cluster IV and Vihar from cluster V were identified to be superior and were from genetically divergent clusters so could be used in hybridization programme to produce transgressive segregants.