International Journal of Cancer Therapy and Oncology
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Cancer & the Kidney International Network’s First Annual Conference in Brussels, Belgium
No full textThe Cancer & the Kidney International Network (C-KIN) will hold its first annual conference on 14-15 April 2015 at the Crowne Plaza Brussels - Le Palace in Brussels, Belgium. Founded in March 2014, C-KIN is the first international network of healthcare professionals, clinicians, and researchers focusing on kidney-related issues in patients with cancer. The C-KIN Annual Conference aims to improve integrated patient care by gathering professionals for networking opportunities and to exchange developments in research and education in the field of onconephrology. Featured topics include evaluation of renal function in cancer patients and renovascular safety of antiangiogenics. Abstract submission for poster presentations is still open. The deadline for online registration discount is 9 February 2015.CLICK HERE for more informatio
Dosimetric comparison among different head and neck radiotherapy techniques using PRESAGE® dosimeter
Get PDFPurpose: The purpose of this analysis was to investigate dose distribution of Three Dimensional Conformal Radiation Therapy (3DCRT), Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for Head and Neck cancer using 3-dimensional PRESAGE® dosimeter. Method: Computer Tomography (CT) scans of Radiological Physics Center (RPC) Head and Neck anthropomorphic phantom with both RPC standard insert and PRESAGE® insert were acquired separated with Philipp’s CT scanner and both CT scans were exported via DICOM to the pinnacle treatment planning system (TPS). Each plan was delivered twice to the RPC phantom first containing the RPC standard insert having Thermoluminescent detectors (TLD) and film dosimeters and then again containing the PRESAGE® insert having three dimensional dosimeter (PRESAGE®) by using a Varian True beam linear accelerator. After irradiation, the standard insert including point dose measurement (TLD) and planner GafChromic® EBT film measurement was read using RPC standard procedure. The 3D dose distribution from PRESAGE® was read out with the Duke Midsized optical scanner dedicated to RPC (DMOS-RPC). Dose volume histogram (DVH), mean and maximal doses for organ-at-risk (OARs) were calculated and compared among each Head and Neck technique. The prescription dose was same for all Head and Neck radiotherapy techniques which was 6.60 Gy per friction. Beam profile comparison and gamma analysis were used to quantify agreement among film measurement, PRESAGE® measurement and calculated dose distribution. Quality assurances of all plans were performed by using ArcCHECK method. Results: VMAT delivered the lowest mean and maximal doses to organ at risk (spinal cord and parotid) than IMRT and 3DCRT. Such dose distribution was verified by absolute dose distribution using TLD system. 2D gamma 5%/3 mm criteria of Pinnacle vs. EBT2 film 3DCRT (92.34%), IMRT (92.3%) and VMAT (96.63%) in axial plan respectively. It was also found that agreement between PRESAGE® and pinnacle along the axial, sagittal and coronal plans VMAT agreement was better than IMRT and 3DCRTplan excludes a 7 mm rim at the edge of the dosimeter using 2D gamma map criteria (±5%/3 mm) with 5% threshold dose. Profile showed good agreement for all plans between film, PRESAGE® and pinnacle. 3D gamma was performed for planning target volume (PTV) and organ at risks (OARs) VMAT and 3DCRT endow with better agreement than IMRT. Conclusion: VMAT delivered lowered mean and maximal doses to organ at risk and better PTV coverage. TLD, EBT film and PRESAGE® dosimeter has suggested that VMAT would be superior modality for the treatment of Head and Neck cancer than IMRT and 3DCRT
High Impact Papers from January – March, 2014
Get PDFHigh impact papers from a particular Issue are selected based on the quality of the article and the number of citations. High impact papers are typically recognized once the Issue completes the publication time period of 12 months. View in PDFFollowing articles are recognized as High Impact Papers from January-March, 2014:Wang H, Vassiliev ON. Microdosimetric characterisation of radiation fields for modelling tissue response in radiotherapy. Int J Cancer Ther Oncol 2014; 2(1):020116.DOI: 10.14319/ijcto.0201.16Read Download Chaikh A, Giraud J, Balosso J. A method to quantify and assess the dosimetric and clinical impact resulting from the heterogeneity correction in radiotherapy for lung cancer. Int J Cancer Ther Oncol 2014; 2(1):020110.DOI: 10.14319/ijcto.0201.10Read Download Rana S. Clinical dosimetric impact of Acuros XB and analytical anisotropic algorithm (AAA) on real lung cancer treatment plans: review. Int J Cancer Ther Oncol 2014; 2(1):02019.DOI: 10.14319/ijcto.0201.9 Read Download (High impact papers from April-June, 2014 will be recognized in the next Issue of the IJCTO
Estimation of transition doses for human glioblastoma, neuroblastoma and prostate cell lines using the linear-quadratic formalism
Get PDFPurpose: The introduction of stereotactic radiotherapy has raised concerns regarding the use of the linear-quadratic (LQ) model for predicting radiation response for large fractional doses. To partly address this issue, a transition dose D* below which the LQ model retains its predictive strength has been proposed. Estimates of D* which depends on the a, β, and D0 parameters are much lower than fractional doses typically encountered in stereotactic radiotherapy. D0, often referred to as the final slope of the cell survival curve, is thought to be constant. In vitro cell survival curves generally extend over the first few logs of cell killing, where D0-values derived from the multi-target formalism may be overestimated and can lead to low transition doses. Methods: D0-values were calculated from first principles for each decade of cell killing, using experimentally-determined a and β parameters for 17 human glioblastoma, neuroblastoma, and prostate cell lines, and corresponding transition doses were derived.Results: D0 was found to decrease exponentially with cell killing. Using D0-values at cell surviving fractions of the order of 10-10 yielded transition doses ~3-fold higher than those obtained from D0-values obtained from conventional approaches. D* was found to increase from 7.84 ± 0.56, 8.91 ± 1.20, and 6.55 ± 0.91 Gy to 26.84 ± 2.83, 23.95 ± 2.03, and 22.49 ± 2.31 Gy for the glioblastoma, neuroblastoma, and prostate cell lines, respectively. Conclusion: These findings suggest that the linear-quadratic formalism might be valid for estimating the effect of stereotactic radiotherapy with fractional doses in excess of 20 Gy
Influence of Geant4 parameters on proton dose distribution
Get PDFPurpose: The proton therapy presents a great precision during the radiation dose delivery. It is useful when the tumor is located in a sensitive area like brain or eyes. The Monte Carlo (MC) simulations are usually used in treatment planning system (TPS) to estimate the radiation dose. In this paper we are interested in estimating the proton dose statistical uncertainty generated by the MC simulations. Methods: Geant4 was used in the simulation of the eye’s treatment room for 62 MeV protons therapy, installed in the Istituto Nazionale Fisica Nucleare Laboratori Nazionali del Sud (LNS-INFN) facility in Catania. This code is a Monte Carlo based on software dedicated to simulate the passage of particles through the matter. In this work, we are interested in optimizing the Geant4 parameters on energy deposit distribution by proton to achieve the spatial resolution of dose distribution required for cancer therapy. We propose various simulations and compare the corresponding dose distribution inside water to evaluate the statistical uncertainties. Results: The simulated Bragg peak, based on facility model is in agreement with the experimental data, The calculations show that the mean statistical uncertainty is less than 1% for a simulation set with 5 × 104 events, 10-3 mm production threshold and a 10-2 mm step limit. Conclusion: The set of Geant4 cut and step limit values can be chosen in combination with the number of events to reach precision recommended from International Commission on Radiation Units and measurements (ICRU) in Monte Carlo codes for proton therapy treatment
Impact of lymphoceles on organ at risk doses in patients undergoing adjuvant pelvic radiation for carcinoma cervix
Get PDFPurpose: Lymphoceles form part of target volume during adjuvant radiation for cervical cancer. The impact of lymphocele on doses to adjacent organs at risk (OAR) has not been studied. The present study was designed to investigate the same. Methods: From January 2011- December 2013 all patients were evaluated for presence of postoperative lymphocele. Planned target volume (PTV) was generated with and without lymphocele volume. Intensity modulated radiation therapy (IMRT) plans were generated and dose to OARs was determined. The impact of lymphocele volume on OAR dose was determined by Spearman rank test and Wilcoxon sign rank sum test was performed to determine the impact of lymphocele on OAR dose. Results: A total of 11/93 patients had postoperative lymphoceles. Of these 63% were located in internal iliac region. The median lymphocele volume at simulation was 42.8 cc (range 6.4-105cc) and remained almost stable at 44 cc (range 3-100 cc) at fifth week of radiation. Negative correlation was observed between mean lymphocele volume and dose to bladder, rectum and bowel bag. Presence of lymphocele led to reduction in V30 and V40 of bladder (84 cc vs 77 cc, p = 0.004; 68 cc vs 63 cc; p = 0.01) and rectum (87 cc vs 80 cc, p = 0.0001; 73.5 cc vs 65 cc, p = 0.01) and V15 of bowel bag (843 cc vs 804 cc; p = 0.01). Conclusion: Presence of lymphoceles displaced OARs leading to reduction in high dose volumes of rectum and bladder
Intestinal pseudo-obstruction: An important diagnostic challenge
Get PDFWe present the case of a 72-year-old patient admitted on various occasions with symptoms of intestinal pseudo-obstruction. Extensive diagnostic tests eventually found that the patient had small-cell lung cancer associated with high anti-HU antibody titres, which pointed to a probable paraneoplastic intestinal obstruction syndrome associated with small-cell lung cancer. A paraneoplastic syndrome causing abnormal changes in gastrointestinal motility can be the first signs of small cell lung cancer. These syndromes improve with treatment of the underlying disease, as seen in our patient, who stopped having episodes of intestinal pseudo-obstruction after administration of chemotherapy
Statistical methods to evaluate the correlation between measured and calculated dose using quality assurance method in IMRT
Get PDFPurpose: the objective of this study is to validate a procedure based on a statistical method to assess the agreement and the correlation between measured and calculated dose in the process of quality assurance (QA) for Intensity-Modulated Radiation Therapy (IMRT).Patients and methods: 10 patients including 56 fields for head and neck cancer treatment were analyzed. For each patient, one treatment plan was generated using Eclipse TPS®. To compare the calculated dose with measured dose a CT-scan of solid water slabs (30 × 30 × 15 cm3) was used. The measurements were done for absolute dose by a pinpoint ionization chamber and 2D dose distributions using electronic portal imaging device dosimetry. Six criteria levels were applied for each case (3%, 3 mm), (4%, 3 mm), (5%, 3 mm), (4%, 4 mm), (5%, 4 mm) and (5%, 5 mm). The normality of the data and the variance homogeneity were tested using Shapiro-Wilks test and Levene’s test, respectively. Wilcoxon signed-rank paired test was used to calculate p-value. Bland-Altman method was used to calculate the limit of agreement between calculated and measured doses and to draw a scatter plot. The correlation between calculated and measured doses was assessed using Spearman’s rank test.Results: The statistical tests indicate that the data do not fulfill normal distribution, p < 0.001 and had a homogenous variance, p = 0.85. The upper and lower limit of agreements for absolute dose measurements were 6.44% and -6.40%, respectively. Wilcoxon test indicated a significance difference between calculated and measured dose with ionization chamber, p = 0.01. Spearman’s test indicated a strong correlation between calculated and absolute measured dose, ρ = 0.99. Therefore, there is a lack of correlation between dose difference for absolute dose measurements and gamma passing rates for 2D dose measurements.Conclusion: the statistical tests showed that the common acceptance criteria’s using gamma evaluation are not able to predict the dose difference for a global treatment plan or per beam. The current QA method is limited to protect the patient. The described method provides an overall analysis for dosimetric data issued from calculation and measurement and it can be quickly integrated in QA system for IMRT
A Monte Carlo model for independent dose verification in IMRT and VMAT for the Varian Novalis TX with high definition MLC
Get PDFPurpose: With intensity modulated radiation therapy (IMRT), the physician can prescribe, design and deliver optimized treatment plans that target the tumor and spare adjacent critical structures. The increased conformity of such plans often comes at the expenses of adding significant complexity to the delivery of the treatment. With volumetrically modulated arc therapy (VMAT), in addition to the modulation of the intensity of the radiation beam, other mechanical parameters such as gantry speed and dose rate are varied during treatment delivery. It is therefore imperative that we develop comprehensive and accurate methods to validate such complex delivery techniques prior to the commencement of the patient’s treatment. Methods: In this study, a Monte Carlo simulation was performed for the high definition multileaf collimator (HD-MLC) of a Varian Novalis TX linac. Our simulation is based on the MCSIM code and provides a comprehensive model of the linac head. After validating the model in reference geometries, treatment plans for different anatomical sites were simulated and compared against the treatment planning system (TPS) dose calculations. All simulations were performed in a cylindrical water phantom as opposed to the patient anatomy, to remove any complexities associated with density effects. Finally, a comparison through gamma analysis of dose plane between the simulation, the TPS and the measurements from the Matrixx array (IBA) was conducted to verify the accuracy of our model against both the measurements and the TPS. Results: Gamma analysis of ten IMRT and ten VMAT cases for different anatomical sites was performed, using a 3%/3 mm passing criterion. The average passing rates were 97.5% and 94.3% for the IMRT and the VMAT plans respectively when comparing the MCSIM and TPS dose calculations. Conclusion: In the present work a Monte Carlo model of a Novalis TX linac which has been tested and benchmarked to produce phase-space files for the treatment head of the linac was used to produce a input phase-space to calculated dose deposition phenomena in different geometries for IMRT and VMAT treatment modalities. The control points defined for the MLC were replaced by blocks with the same characteristics and materials of the linac MLC to speed up the simulation time. With this technique a simulation of a typical IMRT case can be performed with a 10 computer cluster in about 1.02 hours in average. If the number of computer used is increased the computing time can be reduced even more which make our model suitable for clinical use as a second check method to compare the TPS dose calculated. Our results showed that for IMRT and VMAT deliveries with a HD-MLC, there is an average of 95.9% of the points have a gamma index less than 1 with our chosen criterion between our Monte Carlo simulations and the corresponding measurements and TPS calculations in a cylindrical water equivalent phantom. This Monte Carlo code can be used as pre-treatment, independent dose calculation verification for IMRT and VMAT deliveries
High Impact Papers from July – September, 2014
No full textHigh impact papers from a particular Issue are selected based on the quality of the article and the number of citations. High impact papers are typically recognized once the Issue completes the publication time period of 12 months.Following articles are recognized as High Impact Papers from July - September, 2014: Barbosa NA, da Rosa LAR, de Menezes AF, Reis JP, Facure A, Braz D. Assessment of ocular beta radiation dose distribution due to 106Ru/106Rh brachytherapy applicators using MCNPX Monte Carlo code. Int J Cancer Ther Oncol 2014; 2(3):02038. DOI: 10.14319/ijcto.0203.18Read Download Citations Chaikh A, Giraud JY, Balosso J. A 3D quantitative evaluation for assessing the changes of treatment planning system and irradiation techniques in radiotherapy. Int J Cancer Ther Oncol 2014; 2(3):02033. DOI: 10.14319/ijcto.0203.3Read Download CitationsCan an alternative backround-corrected [18F] fluorodeoxyglucose (FDG) standard uptake value (SUV) be used for monitoring tumor local control following lung cancer stereotactic body radiosurgery? DOI: 10.14319/ijcto.0203.17Read Download Citations (High impact papers from October-December, 2014 will be recognized in the next Issue of the IJCTO