International Journal of Cancer Therapy and Oncology
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Pretreatment CT texture features for prognostication in patient with Stage III Non-Small Cell Lung Cancer
Get PDFPurpose: To determine whether CT texture features can yield prognostic information in addition to conventional prognostic factors in stage III non-small cell lung cancer (NSCLC).Methods: We conducted a retrospective review of 91 patients with stage III NSCLC treated with definitive chemoradiation. All patients received a four-dimensional (4D) CT simulation, where we utilized the average image (average-CT) and an expiratory image (T50-CT), and a diagnostic contrast enhanced CT image (CE-CT). A penalized cox regression model was used for covariate selection and model development. Models incorporating texture features from the 3 image types and clinical factors were compared to models incorporating clinical factors alone for overall survival (OS), local-regional control (LRC), and freedom from distant metastases (FFDM). Predictive Kaplan-Meier curves were generated using leave-one-out cross-validation. Stratification into low-risk and high-risk groups was based on a patient’s predicted outcome being greater or less than the median. Reproducibility of texture features was evaluated using test-retest scans from independent patients. The concordance correlation coefficient (CCC) was used to assess texture feature reproducibility and classification accuracy was used to assess reproducibility of texture features within the context of our models. Results: Models incorporating both texture and clinical features demonstrated a significant improvement in stratification compared to models using clinical features alone in cross-validated Kaplan-Meier curves in terms of OS (p = 0.046), LRC (p = 0.01), and FFDM (p = 0.005). The average CCC was 0.89, 0.91, and 0.67 for texture features extracted from the average-CT, T50-CT, and CE-CT, respectively. Incorporating reproducibility uncertainties within our model yielded 80.4 (SD = 3.7), 78.3 (SD = 4.0), and 78.8 (SD = 3.9) percent classification accuracy for OS, LRC, and FFDM, respectively. Conclusion: Pretreatment tumor texture may provide prognostic information in additional to routinely obtained clinical features. Reproducibility of CE-CT appears inferior to average-CT and T50-CT; however model classification accuracy rates of ~80% were still achieved.----------------------Cite this article as: Fried DV, Tucker SL, Zhou S, Liao ZX, Ibbott GS, Court LE. Pretreatment CT texture features for prognostication in patient with Stage III Non-Small Cell Lung Cancer. Int J Cancer Ther Oncol 2014; 2(2):020223. DOI: 10.14319/ijcto.0202.2
Computational system to create an entry file for replicating I-125 seeds simulating brachytherapy case studies using the MCNPX code
Get PDFPurpose: A computational system was developed for this paper in the C++ programming language, to create a 125I radioactive seed entry file, based on the positioning of a virtual grid (template) in voxel geometries, with the purpose of performing prostate cancer treatment simulations using the MCNPX code.Methods: The system is fed with information from the planning system with regard to each seed’s location and its depth, and an entry file is automatically created with all the cards (instructions) for each seed regarding their cell blocks and surfaces spread out spatially in the 3D environment. The system provides with precision a reproduction of the clinical scenario for the MCNPX code’s simulation environment, thereby allowing the technique’s in-depth study.Results and Conclusion: The preliminary results from this study showed that the lateral penumbra of uniform scanning proton beams was less sensitive In order to validate the computational system, an entry file was created with 88 125I seeds that were inserted in the phantom’s MAX06 prostate region with initial activity determined for the seeds at the 0.27 mCi value. Isodose curves were obtained in all the prostate slices in 5 mm steps in the 7 to 10 cm interval, totaling 7 slices. Variance reduction techniques were applied in order to optimize computational time and the reduction of uncertainties such as photon and electron energy interruptions in 4 keV and forced collisions regarding cells of interest. Through the acquisition of isodose curves, the results obtained show that hot spots have values above 300 Gy, as anticipated in literature, stressing the importance of the sources’ correct positioning, in which the computational system developed provides, in order not to release excessive doses in adjacent risk organs. The 144 Gy prescription curve showed in the validation process that it covers perfectly a large percentage of the volume, at the same time that it demonstrates a large decline for short distances.------------------------------Cite this article as: Boia LS, Junior J, Menezes AF, Silva AX. Computational system to create an entry file for replicating I-125 seeds simulating brachytherapy case studies using the MCNPX code. Int J Cancer Ther Oncol 2014; 2(2):02023.DOI: http://dx.doi.org/10.14319/ijcto.0202.
Validation of an integrated patient positioning system: Exactrac and iViewGT on Synergy Platform
Get PDFPurpose: Evaluation of the newly integrated system for its validation and designing a quality assurance frame work to assess its geometrical, radiological and mechanical accuracy.Methods: Isocentric accuracy of two independent imaging modalities, kV based ExacTrac and MV based iViewGT was evaluated using Winston-Lutz test. A pelvic humanoid phantom was used for the radiological end-to-end test for its clinical utilization. Image quality for the systems was evaluated using Las Vegas Phantom and ETR-1 plate. The kV system was also assessed for kVp accuracy, kVp - dose linearity, mAs-dose linearity and timer linearity and its accuracy. The system was tested for total filtration and output consistency. Tests for uniformity and noise measurement of kVp accuracy and its reproducibility, linearity test between applied kVp and the x-ray dose, linearity Test between applied mAs and the x-ray dose were also done. Results: Winston-Lutz test gave the isocentric deviation of 0.058 ± 0.015 mm with the average lateral deviation as 0.028 ± 0.021 mm, average longitudinal deviation as 0.032 ± 0.015 mm and average vertical deviation as 0.030 ± 0.016 mm. With the phantom test, the minimum measured displacement of Exactrac positioning was 0.2 ± 0.3 mm, 0.0 ± 0.2 mm and 0.1 ± 0.3 mm in longitudinal, lateral and vertical directions respectively. In image quality test, visible smallest visible hole size seen by both Exactrac and EPID imaging system was 5 mm and can resolve 1.5 lp/mm or better. The image uniformity was found to be 132.9 ± 3.06 pixels for MV images and 139 ± 4.41 pixels for kV images with the associated noise of ≤1% both for 120 kV-20 mAs and 4 MV beam energy of ExacTrac and iViewGT respectively. The uniformity and noise test, measured pixel intensity values for various points on MV and kV images separately were found to agree within ± 1% with respect to the central axis pixel value. The kVp accuracy and its reproducibility were tested for kV imager only. The deviation of kVp was found to be than ± 1% and its precision was seen to be even lesser than ± 0.1%. Linearity test between applied kVp and the x-ray dose and applied mAs and x-ray dose were tested only for the ExacTrac. Both the coefficient of linearity for kVp as well as mAs was found to be < 0.1. Conclusion: It is feasible to install ExacTrac imaging system with an Elekta linear accelerator. Both the imaging systems were found to be compatible in terms of image quality test and isocentric accuracy and can be used for the patient imaging in the same Linear accelerator.-----------------------------Cite this article as: Jassal K, Munshi A, Sarkar B, Paul S, Sharma A, Mohanti BK, Ganesh T, Chougule A, Sachdev K. Validation of an integrated patient positioning system: Exactrac and iViewGT on Synergy Platform. Int J Cancer Ther Oncol 2014; 2(2):020212. DOI: 10.14319/ijcto.0202.1
Painless pulsatile mass as first presentation of renal cell carcinoma
Get PDFRenal cell carcinoma rarely presents with typical features of abdominal pain, flank mass and haematuria, and up to 30% of patients present with metastases. We present the case of an 81 year old man who presented with a painless, pulsatile sternal metastasis as an initial presentation of renal cell carcinoma. This case highlights the importance of recognizing even unusual presentations of renal cell carcinoma, and that although sternal metastases are rare, when they do occur there should be a low threshold for ruling out renal cell carcinoma.-------------------------------Cite this article as: Hoyland K, Vasdev N, Nathan P, Hanbury D. Painless pulsatile mass as first presentation of renal cell carcinoma. Int J Cancer Ther Oncol 2014; 2(3):02036. DOI: 10.14319/ijcto.0203.
Bilateral pulmonary nodules after the successful treatment of a mediastinal seminoma
Get PDFGerm cell tumors are unusual, but they represent the most common neoplasm in young men. Since the introduction of cisplatin-based chemotherapy, most cases are expected to be cured today. Intensive monitoring of these patients during follow-up is required to rule out relapses or late complications of therapy. We present the case of a 21-year-old male who developed extensive lung dissemination by Langerhans cell histiocytosis eight months after the successful treatment of a bulky mediastinal seminoma.
Extended distance non-isocentric treatment in stereotactic body radiation therapy (SBRT) for lung cancer
Get PDFPurpose: To obtain the maximum differential non-coplanar beams angle for a faster dose dropping outside Plan Target Volume (PTV) for lung cancer treated by Stereotactic body radiation therapy (SBRT), an extended distance non-isocentric (EDNI) treatment method was explored and developed.Methods: The EDNI requires delivering of the treatment beam at 120 cm or farther for sauce axial distance (SAD) instead of standard 100 cm. This change provides a more compact dose distribution around PTV and the lower toxicity to organs at risk (OAR) due to benefit of 120 cm SAD and more choice of beam and couch angle. A hand calculation formula for the translation between 100 SAD and EDNI was used to verify the treatment plan results. A phantom for end to end study based on this EDNI technique was used to compare with standard 100 SAD deliveries for SBRT. Three patients who underwent SBRT treatment were randomly chosen to demonstrate the benefits of EDNI technique. These treatment re-plans were applied to EDNI and evaluated for conformal index (CI) of PTV, R50% of PTV, 2 cm distance (D2cm) of PTV and Maximum dose (Dmax)of OARs to compare with original clinical plans.Results: All of the cases delivered by the EDNI technique satisfied dose requirements of RTOG 0263 and showed a faster dose dropping outside of PTV than standard SAD deliveries. The distance from PTV after 1.5 cm for the EDNI technique had a smaller maximum dose and much lower standard deviation for dose distribution. The EDNI applied plans for patients showed less R50% and D2cm of PTV (P≤ 0.05), also similar results for Dmax of esophagus, trachea and spinal cord.Conclusion: The EDNI method enhances the capabilities of linear accelerators as far as the increased gradient of dose drop-off outside of PTV is concerned. More angular separation between beams leads to more compact dose distributions, which allow decreasing volume of high dose exposure in SBRT treatments and better dose distribution on sensitive organs to minimize the treatment toxicity
In vivo fluorescence spectroscopic monitoring of radiotherapy in cancer treatment
Get PDFPurpose: The primary purpose of this study is to introduce fluorescence spectroscopy technology as a tool for optical biopsy and to evaluate the reliability of this real-time non-invasive technique in assessing tumor therapeutic response in radiotherapy.Methods: Four oral cancer patients with inflammatory conditions of the oral cavity volunteered to participate in the study. Using FastEEM (Excited Emission Matrix), spectra were taken from both normal and tumor regions. Then the second optical diagnostic was taken from the tumor regions in 4 patients with time delay of 4 weeks. The fluorescence spectroscopy optical biopsy turned out to be more suitable for tumor diagnostics as there was a significant difference in fluorescence spectra. Results: The first fluorescence intensity of cancerous tissue was higher compared to the second fluorescence intensity of optical biopsy of cancerous oral tissue. From this result, it can be concluded that the fluorescence spectroscopy optical biopsy, which is a technique that does not require removal of tissue sample from body, is a reliable tool to be used in radiotherapy. Conclusion: FastEEM, which is a tool for fluorescence spectroscopy, enables a real-time non-invasive assessment of the chemical, biological, as well as morphological variations in the tissue composition following radiotherapy
Solitary bone metastasis to the tibia from colorectal cancer- A case report
Get PDFThe onset of osseous metastases during the course of colorectal cancer is not common. Although rare, they usually appear in the axial skeleton. In our report, we refer to the case of a 48-year-old patient who presented with colon cancer and eventually developed a solitary bone metastasis in the upper end of left tibia. At the time of diagnosis and staging investigations, the patient had only a primary disease.------------------------------------------------Cite this article as:Alnajjar A, Mohanty AK. Solitary bone metastasis to the tibia from colorectal cancer- A case report. Int J Cancer Ther Oncol 2014; 2(4):02045. DOI: 10.14319/ijcto.0204.
Digit Ratio (2D:4D) and cancer: What is known so far?
Get PDFThe ratio between the second and fourth digits is a proxy marker for prenatal exposure and sensitivity to sexual hormones, which can be genetically influenced. The influence of prenatal hormone exposure can reflect on adult life traits such as psychological traits, athletic performance and diseases such as cardiovascular. An important and newly explored field on digit ratio research is its correlation to different types of cancer, as a marker for prevalence and severity. In this review, the different types of cancer already correlated to digit ratios are discussed.----------------------------------------------Cite this article as: Hopp RN, Lima N, Filho J, Sena-Filho M, Samuel RO, Amaral JG, Jorge J. Digit Ratio (2D:4D) and cancer: What is known so far? Int J Cancer Ther Oncol 2014; 2(1):020111.DOI: http://dx.doi.org/10.14319/ijcto.0201.1
Geometrical determinations of IMRT photon pencil-beam path in radiotherapy wedges and limit divergence angle with the Anisotropic Analytic Algorithm (AAA)
Get PDFPurpose: Static wedge filters (WF) are commonly used in radiation therapy, forward and/or inverse planning. We calculated the exact 2D/3D geometrical pathway of the photon-beam through the usual alloy WF, in order to get a better dose related to the beam intensity attenuation factor(s), after the beam has passed through the WF. The objective was to provide general formulation into the Anisotropic Analytical Algorithm (AAA) model coordinates system (depending on collimator/wedge angles) that also can be applied to other models. Additionally, second purpose of this study was to develop integral formulation for 3D wedge exponential factor with statistical approximations, with introduction for the limit angle/conformal wedge.Methods: The radiotherapy model used to develop this mathematical task is the classical superposition-convolution algorithm, AAA (developed by Ulmer and Harder). We worked with optimal geometrical approximations to make the computational IMRT calculations quicker/reduce the planning-system time. Analytic geometry/computational-techniques to carry out simulations (for standard wedges) are detailed/developed sharply. Integral developments/integral-statistical approximations are explained. Beam-divergence limit Angle for optimal wedge filtration formulas is calculated/sketched, with geometrical approximations. Fundamental trigonometry is used for this purpose.Results: Extent simulation tables for WF of 15º, 30º, 45º, and 60º are shown with errors. As a result, it is possible to determine the best individual treatment dose distribution for each patient. We presented these basic simulations/numerical examples for standard manufacturing WF of straight sloping surface, to check the accuracy/errors of the calculations. Simulations results give low RMS/Relative Error values (formulated) for WF of 15º, 30º, 45º, and 60º.Conclusion: We obtained a series of formulas of analytic geometry for WF that can be applied for any particular dose delivery model. Simulations results gave acceptable trigonometrical approximations/data that can be used for LINAC applications/planning-system software. The integral formulas presented are practical for dose delivery calculations/3D-approximations when using WF/other similar types of beam modification devices. Limit angle formulation and conformal wedge concept was also presented...................................................Cite this article as: Casesnoves F. Geometrical determinations of IMRT photon pencil-beam path in radiotherapy wedges and limit divergence angle with the Anisotropic Analytic Algorithm (AAA). Int J Cancer Ther Oncol 2014; 2(3):02031. DOI:10.14319/ijcto.0203.