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Publisher: International Journal of Cancer Therapy and Oncology   (Total: 1 journals)   [Sort by number of followers]

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Intl. J. of Cancer Therapy and Oncology     Open Access   (Followers: 6)
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International Journal of Cancer Therapy and Oncology
Number of Followers: 6  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2330-4049
Published by International Journal of Cancer Therapy and Oncology Homepage  [1 journal]
  • Investigation the impact of maximum control point on dose calculation in
           Eclipse treatment planning system for lung SBRT

    • Authors: Sakda Kingkaew, Sawwanee Asavaphatiboon, Lukkana Apipunyasopon
      Abstract: Purpose: Choosing an appropriate parameter on the computerized treatment planning systems (TPSs) influences on the accuracy of dose calculation. Several dosimetric parameters have been studied to achieve a more accurate dose and qualitative plan. The purpose of this study was to determine the impact of maximum control point on the dose calculation on Eclipse TPSs for lung Stereotactic Body Radiation Therapy (SBRT) considering the plan quality, the computation time and the treatment file size.Methods: Dose distributions for the 8 lung SBRT plans with varying maximum control point of 64, 166, and 320 were calculated by Eclipse TPSs with flattening filter free (FFF) beam. The treatment dose was prescribed at 85% isodose level of 54 Gy to the planning target volume (PTV). The dosimetric impact can be evaluated from target coverage, conformity index (CI), homogeneity index (HI), and organ at risk (OAR) doses, while the computation time and the file storage space were compared with the recommended number of control point.Results: The use of 64 control points per subfields tended to increase the dose at PTV and OARs comparing with the 166 and 320 control point plans, while the HI and CI values were similar. The average increases of OARs doses including the spinal cord, heart, esophagus and total lung depended on the photon beam energy. The higher average control point (AVG) number leaded to increase the computation time and the file size for both 6X-FFF and 10X-FFF photon beams. The correlations between AVG and plan storaage space were observed in the same ratio as the computation time.Conclusion: Using the minimal number of control point, the quantitative analysis in the PTV and OARs showed no clinically significant variation in dose, therefore choosing an optimal number of fixed control points leaded to balance the plan quality, the computation time and the file size.
      PubDate: 2017-12-24
      Issue No: Vol. 5 (2017)
       
  • Area-level factors associated with spatial variation of prostate cancer
           incidence for black men

    • Authors: Getachew Dagne, Folakemi Odedina, Nickyjeanna Aime, Mary Ellen Young
      Abstract: Purpose: Black men are disproportionately affected by prostate cancer (CaP) compared to any other racial/ethnic groups within the United States. Identifying CaP hotspots along with associated local area-level risk factors is crucial to tackling the significant burden of CaP and the disparity seen in Black men. The objective of this study was to determine the scope of geographical variation in CaP incidences and to assess the degree to which this variation is associated with county-level risk and protective factors.Methods: The study population was Black men diagnosed with prostate cancer between 2006-2010 in Florida. County-level CaP incidence rates were computed as the ratios of the numbers of new CaP cases diagnosed between 2006 and 2010 to the corresponding 2000 US census population of Black men 20 and over years old data (US Census 2000). Other county-level environmental and health care factors were also obtained. A random effects Poisson model and Geographical Information System (GIS) were used to map and assess the spatial patterns of CaP incidences in 67 Florida counties. These statistical techniques involved a Bayesian approach for estimating the underlying county-specific CaP risk since the data are very sparse.Results: The findings showed that an increasing CaP incidence of Black Men in Florida  was significantly associated with an increasing unemployment rate ( 2     with 95% CI: (.0025, .2703), does not include zero suggesting significance) and with increasing number of physicians per capita after controlling for other county characteristics. There was a negative association between poverty and CaP incidence. Regarding spatial distribution of CaP incidence, we observed that there are clustering and hotspots of high CaP incidence rates in Palm Beach county in South Florida, and Alachua and Marion counties in north Florida.Conclusion: Our findings showed that indicators of socioeconomic status and accessibility of health care services such as poverty, unemployment and health care providers are important variables that explain spatial variation of prostate cancer incidence rates of Black Men. Better understanding of such risk factors and identifying specific counties with a disproportionate burden of CaP disease may help formulate targeted interventions and resource allocation by state and local public officials
      PubDate: 2017-12-24
      Issue No: Vol. 5 (2017)
       
  • Management of Multiple Primary Cancers: What is the Priority'

    • Authors: Xiang Dong, Samuel Barasch, Darren Rohan, Michael Cho, Leno Thomas, Lawrence Koutcher
      Abstract: Multiple primary cancers are known entity due to the propensity of cancer survivors to develop additional malignancies both from genetic predisposition and exogenous influences. However, the development of triple or quadruple primary cancers, especially presenting simultaneously, presents challenging diagnostic and treatment dilemmas. We report here a patient who presented initially with neurological symptoms. Extensive evaluation and pathologic workup revealed that the patient actually has an intra-medullary vascular neoplasm at the level of upper thoracic spine, mucinous adenocarcinoma of the right lower lobe, poorly differentiated adenocarcinoma of the stomach near the gastro-esophageal (GE) junction, and conventional type adenocarcinoma of the hepatic flexure of the colon.  The patient underwent neoadjuvant chemo-radiation for the GE junction carcinoma followed by surgical resection of the three different adenocarcinomas simultaneously as definitive management. This case illustrates the utility of immuno-histochemistry in delineating the site of origin for primary tumors, and the challenges posed when dealing with multiple primary neoplasms concurrently.
      PubDate: 2017-12-24
      Issue No: Vol. 5 (2017)
       
  • Exploring the role of “Glycerine plus Honey” in delaying
           chemoradiation induced oral mucositis in head and neck cancers

    • Authors: Anshuma Bansal, Sushmita Ghoshal, Birender Kumar Yadav, Amit Bahl
      Abstract: Purpose: The purpose of this study was to assess the efficacy of adding “Glycerine plus Honey” to standard management protocol, in terms of time to delay in oral mucositis ≥ grade 2.Methods: Hundred patients of oral cavity and oropharangeal cancers, planned for concurrent chemoradiation (Dose: 60–66 Gy/30-33 fractions) were randomized 1:1 to receive either home-made remedy made of “Glycerine plus Honey” added to the standard management protocol to prevent mucositis versus standard treatment alone. CTCAE v 4 (Common toxicity criteria for adverse events) was used for assessing oral mucositis scores weekly. Chi square test was used to compare mucositis scores, weight loss, opioid use, ryles tube feeding, and unplanned treatment breaks in each cohort. Independent T-test was used to compare means to assess the effect of treatment in delaying mucositis ≥ grade 2.Results: Significantly higher number of patients developed grade ≥ 2 mucositis in control arm [n = 43 (86%)] compared to study arm [n = 30 (60%)] (p = 0.003). CTCAE scores favored Glycerine plus honey at week 4, and on last day of radiotherapy. Whereas, time to first occurrence of oral mucositis grade ≥ 2 was 23.17 (± 1.01) days for study arm [radiation dose 31.67 Gy (± 1.44)], it was 20.65 (± 0.8) days for control arm [radiation dose 28.14 Gy (± 1.16)] (p = 0.05). Study patients had lesser weight loss (2.76 kg) than control subjects (3.9 kg) with p = 0.008. There were significantly higher number of patients in control arm who required opioid analgesia, ryles tube insertion and had unplanned treatment breaks, compared to study arm.Conclusion: Glycerine plus honey demonstrated superiority in delaying oral mucositis, and the combination is safe and well tolerable. 
      PubDate: 2017-12-15
      Issue No: Vol. 5 (2017)
       
  • Clinical characteristics of aggressive Non-Hodgkin lymphoma with emphasis
           on the role of positron emission tomography/computed tomography in
           assessment of treatment response: a retrospective study

    • Authors: Dina Ragab Diab Ibrahim, Wesam Elghamry, Ahmed Mamoun Nofal, Christine Fawzy Hermena
      Abstract: Purpose: The purpose of this study was to evaluate the role of post-treatment Positron Emission Tomography/Computed Tomography (PET/CT) in aggressive non-Hodgkin’s lymphoma (NHL) with regard to the clinical and treatment characteristics and disease-free survival (DFS).Methods: We retrospectively studied charts of 30 patients with aggressive NHL who had PET/CT only after completion of treatment.Results: Thirty patients received CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or Rituximab (R)-CHOP (22 and 8 patients respectively), followed by radiotherapy in 19/30 patients (63.3%). Following 3-4 cycles of chemotherapy, interim CT showed regressive, stationary and progressive disease in 18, 10, 2 (60%, 33.3%, 2%) patients respectively. PET/CT was performed 4-6 weeks after end of treatment. 22/30 (73.3%) patients had negative scan, of whom 13 (59.1%) patients remained in remission till the end of the study while 9 patients relapsed after a median DFS of 12 months. PET/CT was positive in 8/30 (26.7%) patients who had refractory disease. PET/ CT scan had sensitivity of 75%, specificity of 72.7%, negative predictive value (NPV) of 88.9%, and positive predictive value (PPV) of 50%.Conclusion: PET/CT has an important role in end- of- therapy response evaluation in fluorodeoxyglucose (FDG)-avid aggressive NHL. It proves high sensitivity and specificity in detection of residual disease and provides an accurate indication of overall survival and disease-free survival. CT continues to have an important role in post-treatment response assessment whether as a single modality or in combination with PET scan.
      PubDate: 2017-12-15
      Issue No: Vol. 5 (2017)
       
  • Radiobiological assessment of dose-to-medium or dose-to-water with Acuros
           XB algorithm compared with Anisotropic Analytical Algorithm for lung
           cancer radiotherapy- What should we know to manage the transition'

    • Authors: Abdulhamid Chaikh, Catherine Khamphan, Alexia Delbaere, Jarkko Ojala, Robin Garcia, Jacques Balosso
      Abstract: Purpose: To track the dosimetric changes for similar dose prescriptions, when dose calculation algorithms are upgraded in the treatment planning system (TPS). Clinically significant representations of the treatment outcomes are used to provide interpretable data for radiation oncologists, as the equivalent uniform dose (EUD), the tumor control probability (TCP), the late toxicity as normal tissue complication probability (NTCP) and the uncomplicated tumor control probability (UTCP) scores. Results are presented and discussed in a clinical perspective.Methods: Ten lung cancer patients were included in this study. For each patient, five treatment plans were generated. The doses were calculated using Anisotropic Analytical Algorithm (AAA) and both Acuros XB (AXB) dose reporting modes: dose-to-medium AXB D(m,m) and dose-to-water AXB D(w,m). In plans 1, 2 and 3, the doses were calculated respectively with AAA, AXB D(m,m) and AXB D(w,m) using exactly the same prescription dose and beam set-up. The doses in plans 4 and 5 were calculated using both AXB dose reporting modes using, as input, the same number of monitor units (MUs) as yielded by AAA, with the same beam set-up. The EUD, TCP and NTCP were computed using the assumed radiobiological parameters from literature. The Wilcoxon paired test was used to calculate p-values.Results: Using the same prescription dose, TCP values were higher with AXB than with AAA, and corresponding UTCP scores were 1-2% better with p < 0.05. In addition, absolute NTCP values were slightly increased with AXB. Both AXB dose reporting modes yielded comparable lower TCP and NTCP values (again in the order of 1-2%) than with AAA, when using same MU numbers as with AAA.Conclusion: Compared to AAA, taken as reference, both AXB dose reporting modes yielded better results. AAA showed very close values to AXB D(w,m), but it is difficult to give recommendation between D(w,m) and D(m,m) yet, due to the lack of recommended radiobiological parameters associated with these dose reporting modes. We suggest doing experimental and modelling studies to determine the real radiobiological effects in both targets and organs at risks. Should the differences be substantial in some conditions and relevant to clinical practice, discussions regarding dose prescription and optimization of the tolerance doses to OAR should be undertaken between medical physicists and radiation oncologists.
      PubDate: 2017-12-15
      Issue No: Vol. 5 (2017)
       
  • The efficacy of the quercetin analogue LY294002 in immortalized cancer
           cell lines is related to the oxygenic and metabolic status of cells

    • Authors: Xinyue Huang, Michelle Potter, Ben Pilgrim, Ruchuta Ardkhean, Mikail Kabeshov, Tim DW Claridge, Matt Wiseman, Karl J Morten, Timothy J Donohoe, Helen Elizabeth Townley
      Abstract: Purpose: LY294002, a promising drug for chemotherapy, suppresses the activity of Phosphatidylinositol 3-Kinase (PI3K) which is pivotal to a number of processes such as proliferation, metabolism, and apoptosis. The compound has, however, been seen to have very variable efficacy in vivo.Methods: Proliferation and viability of two immortalized cells with divergent bioenergetic profiles was determined using crystal violet staining, and the 3-(4, 5-dimethylthiazol-2yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Oxygen consumption rates were determined using MitoXpress-Xtra probes, and lactate generation was assessed with pH-Xtra probe and BM-lactate strips. Immunoblotting was performed with phospho-Akt-Ser 473 and Akt-pan primary antibodies.Results: U87 cells were shown to have a glycolytic metabolism, whereas RD cells exhibited a more aerobic metabolism. In both lines, hypoxia was shown to increase lactate production, and LY294002 reduced lactate production. The drug decreased cell proliferation and viability under all conditions, but the effect was greatest in U87 cells under normoxic conditions.Conclusion: Metabolic analysis showed a link between a glycolytic cell status and LY294002 induced cell death. However, in both cell lines the drug was also less effective under hypoxic conditions, as would be found in a tumour in vivo. Furthermore, in the presence of LY294002 the phosphorylation status of Akt, a target of PI3K, was found to be related to both the mechanism of cell respiration, and the oxygenic status of the cells.
      PubDate: 2017-12-10
      Issue No: Vol. 5 (2017)
       
  • Evaluation of Eclipse 3D plans using an independent treatment planning
           system

    • Authors: Anil kumar Ayyalasomayajula, Komanduri Ayyangar, Srinivas Vuppu, Akula Roopa Rani, Paladugu venkata Lakshmi Narayana, Angalakuduru Durga Prasada Rao
      Abstract: Purpose: The goal of the current investigation was to compare complex 3D conformal plans generated on Eclipse™ treatment planning system (TPS) with independent dose calculations from radiation oncology planning system (ROPS™) TPS used as a secondary quality assurance check.Methods: Fifteen cancer patients that were treated with complex conformal treatment plans with cobalt and linac beams, using Eclipse TPS, were selected for this study. The structure sets, treatment beam data and prescription information were exported from the Eclipse TPS using DICOM-RT export. Using custom software, these data were imported into ROPS TPS. Independent dose calculation on the ROPS planning system using Clarkson summation algorithm was done. The dose volume histograms (DVH) from both planning systems were extracted and analyzed using custom software. Dose assessment was accomplished by defining criteria based on gross tumor volume (GTV) dose coverage, dose homogeneity and mean dose. For organs at risk (OAR) other than GTV, the main dose parameters were, mean dose and percentage of volume receiving 95% of prescription dose.Results: For the GTV, all 15 cases met the criteria set for the mean dose and dose homogeneity index. However, breast cases were found to have deviation in the percentage volume receiving the 95% of prescription dose.Conclusion: Using the criteria set for plan acceptance, all the 15 clinical cases were evaluated. Except for breast tangent plans, all plans passed all the criteria set. The large deviation for breast tangent plans was attributed to differences in dose calculation algorithms.
      PubDate: 2017-12-10
      Issue No: Vol. 5 (2017)
       
  • A preliminary investigation on long-term consistency of MPC as a quick
           daily QA application

    • Authors: CP Bhatt, Manoj Kumar Semwal, Sukhvir Singh, Kundan Singh Chufal, Kiran Sharma
      Abstract: Purpose: The purpose of this study was to establish Machine performance check (MPC) application as a comprehensive daily QA program in a clinical setting for a True Beam 2.0 system and investigate the first ten months (195 days) daily QA data generated by the MPC.Methods: An automated daily quality assurance (QA) application named machine performance check (MPC) was recently launched by Varian Medical Systems with their TrueBeam 2.0 linear accelerator (linac) system. MPC performs all the essential machine tests such as Beam Constancy Check, and Geometry Check with the use of an IsoCal phantom. There is no systematic published study on long-term consistency and validation of MPC in a clinical set-up for its acceptance as an alternative QA application. In the present study, we collected data with the MPC for over ten months (195 days) on a TrueBeam 2.0 system. The data was analysed for reproducibility and also compared with the data collected with other statndard QA devices at the time of commissioning of the TrueBeam system for validation.Results: The results showed that the reproducibility of MPC was at least an order of magnitude less than the tolerance values for the respective parameters and also the average measured values for all QA parameters studied. The MPC measured isocenter accuracy, and output values were close to the Winston-Lutz test (within 0.1 mm) and the ion-chamber measurements (within 0.1%), respectively.Conclusion: With our long term result, it is evident that the MPC could be an alternative daily QA tool. A comprehensive and long-term validation of the MPC measured values with the other standard QA methods over the ten month period will be needed before accepting MPC as a reliable QA tool.
      PubDate: 2017-12-10
      Issue No: Vol. 5 (2017)
       
  • Evaluation of ArcCHECK SNC Machine QA tool for Modern Linear Accelerator

    • Authors: Vaibhav R Mhatre, Parimal Patwe
      Abstract: Purpose: ArcCHECK SNC Machine QA tool is used to test geometric and delivery aspects of linear accelerator.Methods: In this study we evaluated the performance of this tool. For each item analyzed by the tool, wherever possible, tests across the same time period using portal dosimetry were also evaluated. Machine QA feature allows user to perform quality assurance tests using ArcCHECK phantom. Following tests can be performed 1) Gantry Speed, Rotation and Angle 2) MLC/Collimator 3) Beam Profile Flatness and Symmetry. Data was collected on true BEAM STx for a year. All plans were created for 6 and 10 MV beams as per the SNC patient user manual in Eclipse v.13.Results: The Gantry speed was 3.9 deg/sec with speed maximum deviation around 0.3 deg/sec. The Gantry Isocenter for arc delivery was 0.9 mm and static delivery was 0.4 mm which was well consistent with MPC (0.4 mm). The average maximum percent positive and negative diff was found to be 1.9%, -0.25% and average maximum distance positive and negative diff was 0.4 mm, -0.3 mm for MLC/Collimator QA. The average gamma error at 1% 1 mm criteria was 1.4% using portal Dosimetry for 6 MV. The Flatness for Arc delivery was 1.8% and Symmetry for Y was 0.8% and X was 1.8%.Conclusion: ArcCHECK SNC Machine QA tool is useful for quality assurance of modern linear accelerators as it tests both geometric and delivery aspects. This test can be incorporated in the regular quality assurance protocol for VMAT delivery.
      PubDate: 2017-10-15
      Issue No: Vol. 5 (2017)
       
  • The advantages of collimator optimization for intensity modulated
           radiation therapy

    • Authors: Brian E Doozan, Farrah Mohamed, Erika Nourishirazi, Silvia Pella, Theodora Leventouri
      Abstract: Purpose: The goal of this study was to improve dosimetry for pelvic, head and neck and other cancers with aspherical planning target volumes (PTV) using collimator optimization for intensity modulated radiation therapy (IMRT).Methods: A retroactive study on the effects of collimator optimization of 20 patients was done by comparing collimator angles from optimized plans in Eclipse version 11.0. Keeping all other parameters equal, plans were created with four collimator techniques: CA0, all fields have collimators set to 0°, CA­E, using the Eclipse collimator optimization, CAA­, minimizing the area of the jaws around the PTV, and CAX, minimizing the x-jaw gap. The minimum area and the minimum x-jaw angles were found by evaluating each field beam’s eye view of the PTV with ImageJ and finding the desired parameters with a custom script. The evaluation of the plans included the monitor units (MU), the maximum dose of the plan, the maximum dose to organs at risk (OAR), the conformity index (CI) and the number of split fields. Results: Compared to the CA0 plans, the monitor units decreased on average by 6% for the CAX with a p-value of 0.01 from an ANOVA test. The average maximum dose stayed within 1.1% between all four methods with the lowest being CAX. The maximum dose to the most at risk organ was best spared by the CAA, which decreased by 0.62% from the CA0. Minimizing the x-jaws significantly reduced the number of split field from 61 to 37.Conclusion: In every field tested the CAX optimization produced as good or superior results than the other three techniques. For aspherical PTVs, CAX on average reduced the number of split fields, the maximum dose, minimized the dose to the surrounding OAR, and reduced the MU all while achieving the same control of the PTV.
      PubDate: 2017-08-28
      Issue No: Vol. 5 (2017)
       
  • The bootstrap method to improve statistical analysis of dosimetric data
           for radiotherapy outcomes

    • Authors: Abdulhamid Chaikh, Jean-Pierre Bresciani, Jacques Balosso
      Abstract: Purpose: The purpose of this study is to validate a new technique in radiotherapy, the medical physicist needs to evaluate the dosimetric benefit and the risk of toxicity before integrating it in the clinical use.Methods: We validate a sound decision tool based on bootstrap method to help the radio oncologist and the medical physicist to usefully analyze the dosimetric data obtained from small-sized samples, with few patients. Statistical investigation principles are presented in the framework of a clinical example based on 36 patients with 6 different cancer sites treated with radiotherapy. For each patient, two treatment plans were generated. In plan 1, the dose was calculated using Modified Batho's (MB) density correction method integrated with pencil beam convolution (PBC) as type (a) algorithm. In plan 2, the dose was calculated using Anisotropic Analytical Algorithm (AAA) as type (b) algorithm. The delivered doses in monitor units (MUs) were compared using the two plans. Then, the bootstrap method was applied to the original data set to assess the dose differences and evaluate the impact of sample size on the 95% confidence interval (95%.CI). Shapiro-Wilks and Wilcoxon signed-rank tests were used to assess the normality of the data and determine the p-value. In addition, Spearman’s rank test was used to calculate the correlation coefficient between the doses calculated with both algorithms.Results: A significant difference was observed between AAA and MB for all tested radiation sites. Spearman’s test indicated a good correlation between the doses calculated with both methods. The bootstrap simulation with 1000 random samplings can be used for small populations with n = 10 and provides a true estimation.Conclusion: one must be cautious when implementing this method for radiotherapy: the data should be representative of the real variations of the cases and the cases should be as homogeneous as possible to avoid bias of over/under estimation of the results.
      PubDate: 2017-08-10
      Issue No: Vol. 5 (2017)
       
  • Multileaf-collimator daily quality assurance of Vero4DRT system: our
           one-year experience

    • Authors: Hideharu Miura, Shuichi Ozawa, Shintaro Tsuda, Kiyoshi Yamada, Yasushi Nagata
      Abstract: Purpose: We assessed the daily quality assurance (QA) of multi-leaf collimator (MLC) using the Vero4DRT system. Methods: As part of daily MLC QA, the irradiation field was set to 100 × 150 mm2 with a gantry angle of 0 º. Only the leaf positioning error values only were displayed. We developed an in-house program to easily acquire these values using an open source optical character recognition engine. This test was implemented between 24 August 2015 and 23 August 2016. Results: The maximum leaf positioning error was 0.40 mm in both banks. In addition, the maximum deviation was 0.10 mm in both banks. The average and standard deviation for left and right banks were 0.19 mm ± 0.11 mm and 0.15 mm ± 0.09 mm, respectively. In our one-year measurement, the leaf positioning error was less than 0.50 mm. Therefore, if the leaf position error for daily MLC QA exceeded 0.50 mm, then an external intervention is required.Conclusion: The daily MLC QA of our one-year evaluation of the Vero4DRT system demonstrates an excellent leaf accuracy and reproducibility, thereby giving confidence in the quality of the treatment.
      PubDate: 2017-08-10
      Issue No: Vol. 5 (2017)
       
  • Preferred treatment position between supine and prone for pelvic radiation
           therapy; quantification of the intrafractional body motion component by 3D
           surface imaging system

    • Authors: Hui Zhao, Vikren Sarkar, Long Huang, Brian Wang, Prema Rassiah-Szegedi, Y. Jessica Huang, Martin Szegedi, Victor Gonzalez, Bill Salter
      Abstract: Purpose: We investigated the preferred treatment position between supine and prone during pelvic radiation treatment using real time tracking data from AlignRT. Our findings will provide valuable information regarding the role of intrafractional body motion in answering the question of prone versus supine position for pelvis radiation. Methods: Ten patients receiving pelvic radiation were enrolled in this study. For each patient, two simulation helical CT scans were performed, one in supine and one in prone position. Body surface contours were automatically generated and then exported to the AlignRT system as reference images. AlignRT continuous patient body motion tracking (1.5 to 2 minutes) was performed for both positions for each patient once per week for five weeks. The equivalent patient body motion along three principle directions was calculated from the six degree of freedom real time patient displacements data. The maximum and the standard deviation (STD) of equivalent patient body motion were calculated, so as the average of maximum and STD of equivalent patient motion over five fractions. These were then compared between supine and prone orientations. Results: A correlation was observed between the intrafractional body motion and large BMI. For overweight/obese patients, the intrafractional body motion was smaller for the supine position in both vertical and longitudinal directions. For normal range BMI patients, we observed no clear advantage for either supine or prone position in both vertical and longitudinal directions. In lateral direction, the intrafractional motion did not have statistically difference between two positions. Conclusion: Our study shows that the amount of intrafractional body motion between supine and prone orientation is correlated with patient BMI. Overweight/obese patients experienced significantly less overall body motion in supine orientation. The preferred treatment position for normal BMI patients was seen to be individually variable.
      PubDate: 2017-08-10
      Issue No: Vol. 5 (2017)
       
  • Clinical implementation of IMRT step and shoot with simultaneous
           integrated boost for breast cancer: A dosimetric comparison of planning
           techniques

    • Authors: Ugo Nastasi, Laura Gianusso, Francesca De Monte, Alessandra Cannizzaro, Paolo Rovea
      Abstract: Purpose: Radiotherapy post-lumpectomy with two coplanar tangent beams is the standard treatment for women with early stage breast cancer. Despite the use of wedges as tissue compensators, the resultant plans often contains a significant dose gradient and 'hot spots' in excess of 15% or more of prescribed dose. In recent years a field-in-field (FIF) dose-compensation technique, which use two standard tangent fields and one or two (rarely three) small beams within these, was developed. It allows to obtain a more uniform dose throughout the target volume in the majority of cases but not in all. This study presents our experience to develop optimal intensity modulated radiation therapy (IMRT) techniques to be applied clinically in those cases where the traditional technique with two tangent fields or its variant field in field (FIF) are unable to achieve a satisfactory planning target volumes (PTVs) coverage and dose objectives to the organs at risk (OARs). Methods: We investigated two pure IMRT plans (named 3F-IMRT and 4F-IMRT) and a hybrid one (H-IMRT). Treatment plans were performed for 7 left-sided and 4 right-sided breasts using simultaneously integrated boost (SIB) planned technique with inverse optimization. Results were compared with those obtained with FIF technique. Dose prescribed was 45 Gy/20 fractions to the breast and 50 Gy /20 fractions to the lumpectomy cavity delivered in 5 fr/week. Dose–volume histograms were generated and parameters as target dose coverage, conformity and homogeneity as well as OARs dose distribution were analyzed. Finally the secondary cancer risk to contralateral breast due to radiation was evaluated as a further parameter for the choice of the optimal plan. Results: Compared to the FIF, the three IMRT plans provided the same target coverage and a better dose conformation, but a worst dose homogeneity of the boost target. The volume of the OARs, receiving higher doses than 15 Gy was reduced but was increased the volume receiving low doses. This causes the increase of the risk of radiation induced cancer, especially for the contralateral breast. For this organ, the highest value of the excess absolute risk (EAR) was associated to the 4F-IMRT, while the lower, to the FIF. Conclusion: The intensity-modulated radiation therapy techniques 5F-IMRT and 4F-IMRT were the best to be applied clinically in those cases, where the traditional technique of irradiation of the breast is unable to achieve the PTVs coverage and dose objectives to the OARs. However, all the IMRT techniques showed an increased volume of healthy tissues receiving low doses, so they should not be used in extensive manner and in particular should be avoided in the cases of young women due to the excess of risk to develop a secondary cancer.
      PubDate: 2017-08-10
      Issue No: Vol. 5 (2017)
       
  • Stability assessment of radiation isocenter with the gimbaled linac system

    • Authors: Hideharu Miura, Shuichi Ozawa, Shintaro Tsuda, Kiyoshi Yamada, Yasushi Nagata
      Abstract: Purpose: We report the results of our year-long radiation isocenter accuracy verification for daily quality assurance (QA) implementation on a Vero4DRT system. Methods: The radiation isocenter was calculated using a cube phantom with a steel ball of diameter 10 mm fixed to the center of the phantom. A single photon beam was set with a field size of 100 × 100 mm2. Coincidence of the centroid of the steel ball at kiloVolt X-ray imaging isocenter and megaVolt beam radiation isocenter at each gantry and ring angle was tested. This procedure was performed for gantry angles of 0°, 90°, 180°, and 270°, and ring angles of 0°, 20°, and 340°. The centroid of the steel ball and the center of the radiation field were calculated to analyze the radiation isocenter error. This analysis was automatically calculated using the Daily Check tool in the Vero4DRT system. This QA was implemented between 24 August 2015 and 23 August 2016.Results: The average and standard deviation for pan and tilt directions were 0.12 ± 0.10 mm and -0.20 ± 0.13 mm, respectively. The maximum radiation isocenter accuracy error was 0.50 mm in both directions. Conclusion: The radiation isocenter alignment for the one year duration of the experiment was performed with high accuracy.
      PubDate: 2017-08-10
      Issue No: Vol. 5 (2017)
       
  • Cloning and expression of the V-domain of the CD166 in prokaryotic host
           cell

    • Authors: Hassan Dana, Vahid Marmari, Ali Mazraeh, Ali Ghamari, Mohammad Mahdi Forghanifard
      Abstract: Purpose: CD166/ALCAM (Activated leukocyte cell adhesion molecule) as an immunoglobulin is implicated in cell migration. It is also involved in tumorigenesis of CRC (colorectal cancer) and known as a cancer stem cell marker. CD166, as a membrane protein, potentially represents either diagnostic or therapeutic capacities for CRC.Methods: In this study, the sequence of V domain was optimized for expression in prokaryotic host using online tools and cloned into pET-28a plasmid. The recombinant pET28a was transformed into the E. coli BL21DE3 using heat shock method and expression of recombinant V domain was examined using SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis).Results: The results confirmed protein expression of recombinant 22.77 kDa V domains in bacterial expression system.Conclusion: V domain of the CD166 was expressed successfully in E. coli bacteria. This recombinant fragment can be introduced as a suitable diagnostic and therapeutic candidate for screening and cancer-therapy of CRC patients, respectively. 
      PubDate: 2017-06-25
      Issue No: Vol. 5 (2017)
       
  • Gamma Putty shielding effect in megavoltage photon beam

    • Authors: Aime M Gloi
      Abstract: Purpose: Traditionally, lead and Cerrobend have been employed for field shaping in radiation therapy. Lately, another shielding material called Gamma Putty has emerged. The objective of this report is to examine its dosimetric and shielding characteristics in megavoltage photon beam.Methods: All measurements were carried out in a dual energy linac. Data were collected using a calibrated ionization chamber. Percent transmission, linear attenuation, and field size dependence were evaluated for open square fields (4 × 4 cm2 to 10 × 10 cm2) defined by collimator jaws and for different Gamma Putty thicknesses (t = 0, 0.3, 0.5, 1.0, 1.5, 2.0, and 2.5 cm) at 6 and 18 MV photon beams. The measurements were performed both in air using appropriate acrylic buildup cap and in solid water.Results: The Gamma Putty tray factor (GPTF) increased steadily with field size for both 6 and 18 MV. It was characterized by a half value thickness (HVT) of 2.513 ± 0.101 and 2.855 ± 0.024 cm for 6 and 18 MV, respectively. The reduction in surface dose was about 6%, 14.5%, 22%, 36.37%, and 54% for 6 MV and 2.75 %, 9.36 %, 16.25 %, 28.95 %, and 44.47 % for 18 MV for Gamma Putty thicknesses of 0.3, 0.5, 1.0, 1.5, 2.0, and 2.5 cm.Conclusion: The result of Gamma Putty shielding on the photon beam output increases with thickness, beam energy, and field size. Therefore, clinical use of Gamma Putty tray factors should be tailored for all thicknesses, beam energies, and field sizes. 
      PubDate: 2017-06-25
      Issue No: Vol. 5 (2017)
       
  • The comparison between TP53 gene polymorphisms (c.[215G>C]) homozygotes
           and heterozygotes in Breast Cancer Patients: A clinicopathological
           analysis

    • Authors: Joanna Huszno, Ewa Grzybowska, Marta Nycz Bochenek, Zofia Kołosza, Karolina Tęcza, Jolanta Pamuła Piłat, Magdalena Mazur, Elżbieta Nowara
      Abstract: Purpose: TP53 is a tumor suppressor gene which participates in regulation of cell cycle check points, DNA repair, and apoptosis. The aim of this study was to compare TP53 germ line gene polymorphisms (c.[215G>C]) wild – type homozygotes GG with heterozygotes GC according to clinicopathological factors.Methods: We reviewed the medical records of 87 (22% TP53 gene homozygotes and 78% heterozygotes) breast cancer patients who were diagnosed and treated in COI in Gliwice. Polymorphism profile was assessed by RFLP-PCR technique.Results: The presence of lobular invasive carcinoma was observed insignificantly more often in homozygotes, especially in the group of patients at the age below 50 years (29% vs. 4%, p = 0.095). Patients being TP53 gene heterozygotes had larger tumor size (T > 2) than homozygotes (16% vs. 5%, p = 0.450). There was observed a tendency to the presence of lymph node metastases (53% vs. 34%, p = 0.182) and higher Ki67 (> 20%) (69% vs. 46%, p = 0.209) in TP53 gene homozygotes. HER2 overexpression was associated with TP53 heterozygotes, especially in the group of patients at the age above 50 years (33% vs. 8%, p = 0.144). A negative receptor status was reported more frequently in homozygotes (43% vs.21%, p = 0.340) in patients with age below 50 years. Similarly higher histological grade G3 was detected more often in homozygotes in patients at the age below 50 years (80% vs. 33%, p = 0.130).Conclusion: TP53 gene homozygotes and heterozygotes differ from each other in respect of clinicopathological factors such as: histological type, lymph node metastases, higher Ki67 (> 20%), histological grade G3, ER/PR status, tumor size (T > 2), HER2 overexpression, cancer in family history and diabetes. Patient’s age was associated with the pathological characteristics of tumor.
      PubDate: 2017-06-25
      Issue No: Vol. 5 (2017)
       
  • Is targeting glycolysis with 2-deoxyglucose a viable therapeutic approach
           to bladder cancer'

    • Authors: Vladimir Valera, Mark Ferretti, Derek Prabharasuth, Matthew Chaimowitz, Muhammad Choudhury, John Phillips, Sensuke Konno
      Abstract: Purpose: Although several therapeutic options for bladder cancer are available, the poor efficacy and palpable side effects are a major concern. Establishing a more effective intervention is urgently demanded. Glycolysis is considered a strategic target and has been often investigated in various cancers. Particularly, 2-deoxyglucose (2DG), a glycolysis inhibitor, has been intensely studied and shown to be encouraging and promising. Accordingly, we investigated how targeting glycolysis with 2DG would be effective on bladder cancer cells.Methods: Bladder cancer 5637 cells were employed and cell viability was determined by MTT assay.  To explore the anticancer mechanism of 2DG linked to glycolysis, two glycolytic parameters of hexokinase (HK) activity and ATP synthesis, metabolic signaling pathways, and induction of apoptosis were examined. Whether 2DG may potentiate several chemotherapeutic drugs being clinically used was also assessed for its possible chemosensitizing effect.Results: A dose-dependent study of 2DG showed a 23-80% reduction in cell viability.  HK activity and cellular ATP level were decreased by ~46% and ~56% with 2DG, respectively, indicating the glycolysis inhibition.  AMP-activated protein kinase was activated while protein kinase B was inactivated and also mammalian target of rapamycin was inhibited with 2DG.  These modulations would lead to the growth cessation and the cell viability reduction. In fact, the down-regulation of anti-apoptotic bcl-2 and the up-regulation of pro-apoptotic Bax in 2DG-treated cells indicated induction of apoptosis. Moreover, chemotherapeutic drugs with poor cytotoxic activity were selectively sensitized with 2DG, resulting in a significantly improved cell viability reduction.Conclusion: 2DG has anticancer activity on bladder cancer cells and its anticancer mechanism involves the glycolysis inhibition, the modulations of certain signaling pathways, and induction of apoptosis. Additionally, 2DG has a chemosensitizing effect when combined with drugs. Thus, targeting glycolysis with 2DG appears to be an alternative, viable therapeutic approach to bladder cancer.
      PubDate: 2017-02-12
      Issue No: Vol. 5 (2017)
       
 
 
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