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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)
Journal Cover International Journal of Cancer Therapy and Oncology
  [6 followers]  Follow
    
  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]
  • Estimation of linear quadratic (LQ) model parameter alpha/beta (α/β) and
           biologically effective dose (BED) for acute normal tissue reactions in
           head and neck malignancies

    • Authors: Mirza Athar Ali, Shankar Lal Jakhar, Dharam Pal Punia, MR Bardia, Ajay Sharma, HS Kumar, Sandeep Jain, Neeti Sharma, Vinod Agrawal, Kamlesh Kumar Harsh, Ashok Kumar Kalwar, Muntimadugu Babaiah, Prabhakar Mariappan, N Madhusudhan, Sujana Priya Vuba
      Abstract: Purpose: Linear-Quadratic (LQ) model has been widely used for describing radiobiological effectiveness of various fractionation schedules on tumour as well as normal tissues. This study estimates α/β for acute normal tissue reactions using Fe-plot method.Methods: 50 cases of locally advanced head and neck squamous cell carcinoma (stage III and IV) treated with external beam radiotherapy were included in this study. Patients were randomly distributed into Hyper-fractionation (HF) arm (1.2 Gy/fraction, twice daily, 6 hours apart) and conventional fractionation (CF) arm (2 Gy/fraction, once daily) with 25 cases in each arm. α/β and BED were calculated for acute normal tissue reactions using Fe-plot method.Results: In our study, the estimated values of α/β for RTOG (Radiation Therapy Oncology Group) grade 1, 2 and 3 skin reactions were 11.2 Gy, 10.1 Gy and 9 Gy respectively. Estimated values of α/β for RTOG grade 1, 2 and 3 mucosal reactions were 9.7 Gy, 8.0 Gy and 9.1 Gy respectively. For Hyper-fractionation arm, calculated BED values for grade 1, 2 and 3 skin reactions were 54.45 Gy11.239, 66.90 Gy10.114 and 73.43Gy9.001 respectively and for grade 1, 2 and 3 mucosal reactions were 33.5 Gy9.797, 57.8 Gy8.011 and 70.8 Gy9.106 respectively. For conventional fractionation arm, calculated BED values for grade 1, 2 and 3 skin reactions were 54.09 Gy11.239, 66.88 Gy10.114 and 73.33 Gy9.001 respectively and for grade 1, 2 and 3 mucosal reactions were 33.52 Gy9.797, 57.68 Gy8.011 and 70.73 Gy9.106 respectively.Conclusion: LQ model and the concept of BED provide an excellent tool to compare different fractionation schedules in radiotherapy. The estimated values of α/β for acute reacting normal tissues are in good agreement with the available literature.
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Guanylyl Cyclase C as a tumor marker for detection of circulating tumor
           cells in the peripheral blood of colorectal cancer patients

    • Authors: Meysam Moghbeli, Somaye Chavoshi, Mahmud Tavallaie, Ezzat Dadkhah, Reza Raeissosadati, Moein Farshchian, Mohsen Towliat Kashani, Azita Ganji, Ali Jangjoo, Samaneh Bromand Noughabi, Mohammad Reza Abbaszadegan
      Abstract: Purpose: Guanylyl cyclase C (GCC) is one of the most frequent tumor markers to detect the circulating tumor cells (CTCs) in peripheral blood of colorectal cancer (CRC) patients. It has been proposed as a new marker for the molecular staging of CRC. The level of GCC mRNA expression in peripheral blood of CRC patients was evaluated to explore its probable correlations with the clinicopathological features.Methods: Relative quantitative expression analysis of GCC mRNA was performed on 80 blood samples (40 patients and 40 normal) using the Real-time RT-PCR.Results: GCC mRNA expression was detected in 70% of the CRC blood samples. The level of GCC mRNA expression in peripheral blood of patients was significantly higher than that in the normal cases (p = 0.031). Moreover, there was a significant correlation between the GCC copy number and advanced stages of tumor (p = 0.041). Furthermore, we have observed a significant correlation between tumor sizes and GCC copy numbers (p = 0.050).Conclusion: GCC can be a useful marker not only for detection of CTCs in CRC blood samples, but also for the molecular staging of colorectal cancer. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Role of preoperative 18-FDG- PET/CT in early-stage breast cancer upstaging
           and modification of treatment

    • Authors: Anshu Tewari, Shanmuga Palaniswamy Sundaram, Padma Subramanyam
      Abstract: Purpose: The aim of this study was to assess the diagnostic and therapeutic impact of preoperative positron emission tomography and computed tomography (PET/CT) in the initial staging of patients with early-stage breast cancer.Methods: A total of 72 consecutive patients (age: range 24-78 years, mean 51 years), with newly diagnosed operable breast cancer (Infiltrating Ductal carcinoma: Lobular carcinoma: Others - 49:15:8) with tumor size 10-65 mm were examined preoperatively. All patients underwent conventional assessment imaging modalities like mammography, breast/axillary ultrasound and PET/CT.Results:  PET/CT identified a primary tumor in all but two patients. PET/CT solely detected unsuspected distant metastases (bones, lung, brain etc) in 9 patients and new primary cancers (endometrium and lung) in another two patients, as well as 11 cases of extra-axillary lymph node involvement. In 6 patients, extra-axillary malignancy was detected by PET/CT only, leading to an upgrade of initial staging in 9% (6/70) and ultimately a modification of planned treatment in 12% (9/70) of patients. PET/CT evaluation led 5 patients of stage II A to stage IV, 3 patients of stage II B to stage IV and 1 patient to Stage IIIB which further modified treatment plan from an adjuvant to a metastatic approach.Conclusion: PET/CT is a valuable tool to provide information on extra-axillary lymph node involvement, distant metastases and other occult primary cancers. Preoperative 18F fluorodeoxyglucose PET/CT has a substantial impact on initial staging and on clinical management in patients with early-stage breast cancer.
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Dose-to-medium vs. dose-to-water: Dosimetric evaluation of head and neck
           VMAT cases using Monaco treatment planning system

    • Authors: Saravana Kumar Gopal, Purendra Chandra Dash
      Abstract: Purpose: In this paper, we evaluate the dosimetric differences between absorbed dose to water and absorbed dose to medium in Monte Carlo (MC)-based calculations used for radiation therapy treatment plans.Methods: Thirty-four treated Head and Neck simultaneously integrated boost cases were analyzed retrospectively. All of them were planned by Monaco treatment planning system (TPS), calculated and reviewed on absorbed dose to medium (Dm) calculations and treated in Elekta Versa HD LINAC. Absorbed dose to medium Dm was converted to absorbed dose to water Dw in Monaco treatment planning system using the procedure based on stopping power ratios and the Bragg-Gray cavity theory. Dosimetric parameters were then compared and analyzed with respect to absorbed dose to medium (Dm) calculations for multiple planning target volumes (PTVs) and critical organs such as brainstem, spinal cord, left and right lens, left and right parotids, larynx, left and right middle ear and lips.Results: It was found that mean and minimum Dw (i.e. Dw mean and Dw min) of organs at risk did not differ much (hardly differing by 0.8-2%) with respect to those of the absorbed dose to medium. However maximum Dw (i.e. Dw max) in case of lips, left and right middle ear were found to differ more than 4% with respect to Dm max. For serial organs brainstem and spinal cord, maximum dose Dw max were found to vary around 1% and 2%, respectively, with respect to absorbed dose to medium dose calculation. In case of PTVs, the mean percentages variation of Dw min and Dw mean were found to be less than 1 %, although the variation of maximum Dw was found to be high around 5-7% with respect to that of Dm.Conclusion: The comparative analysis of dosimetric parameters in the present study shows that the selection of either Dm or Dw in Monaco planning system is less likely to produce any significant clinical effect in tumor control and to the damage of organs at risk.
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Independent absolute dose calculation using the Monte Carlo method on
           CT-based data

    • Authors: Nakorn Phaisangittisakul, Lukkana Apipunyasopon, Wasuma Rakkrai
      Abstract: Purpose: The accuracy of delivered dose is essential to the quality of radiotherapy treatment and tumor response. Generally, there are many types of dosimeter have been used to verify the dose from the treatment; however, most of these dosimeters are impractical for clinical situation. The goal of this study was to assess an absolute dose derived from the Monte Carlo (MC) method for the so-called 6- and 10-MV photon beams obtained from Varian Clinac 2100C linear accelerator.Methods: The deposited doses have been calculated by the EGSnrc code system and, then, were converted into the absolute doses. We were also measured, in water phantom, by an ionization chamber and, in the chest region of Rando phantom, by a thermoluminescense dosimeter (TLD).Results: The simulated data in water phantom agree with the results from both the measurement and previous studies within 2%. By comparing the absolute dose at various positions within the Rando phantom from two-opposing irradiated fields, the difference from MC calculation and TLD measurement was within 2%. Unfortunately, the calculated doses obtained from the collapse cone convolution (CCC) algorithm showed notable difference from that of the MC method. For the interface region within the provided field, it was higher than that from the MC method by almost 5% for the 6-MV and 7% for the 10-MV photon beam.Conclusion: Our findings indicated that the MC method was on the level with the measurement for the dose determination, especially within the delivered field to a heterogeneous phantom.
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Novel strategy for the development of radioresistance breast cancer cell
           line

    • Authors: Madhu Leelavathi Narayana, Shama Rao, Sarojini Balladka Kunhanna
      Abstract: Purpose: Fractionated radiation dose therapy is a routine procedure for the breast cancer treatment. However, despite of continuous improvement, tumor recurrence occurs in high proportion of the patients. There is a need of suitable radioresistance cell line system to study the properties of tumor recurrence. But, developing a radioresistant cancer cell line is a time requiring process. It requires a multiple radiation dosages for a period of three to four months. The present study aims for the new strategy to develop a radioresistant breast cancer MCF-7 cell line.Methods: The cells were exposed to 4Gy dosage of ϒ rays prior to 10Gy dose and subjected for clonogenic assay. The cells survived in the clonogenic assay were pooled and named as RR-MCF-7. These cells were subjected to Bcl-2 analysis, apoptotic assay and LDH assay.Results: Developed cell line, RR-MCF-7 showed enhanced expression of Bcl-2 protein, which resulted in the declined apoptotic cell percentage. Though there was destabilization in the membrane of the irradiated cells, there was no significant difference observed in LDH level. Cloning efficiency of the 10 Gy exposed cells was found to be more when it was given a 4 Gy of prior dosage. The cells survived with this dosage showed the resistant character.Conclusion: The approach followed in the current study for developing radioresistant cell line has reduced the time and dose requirement, also succeeded in obtaining resistant characters in it. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Low-dose versus high-dose radioactive iodine ablation of differentiated
           thyroid carcinoma: a prospective randomized study

    • Authors: Dina Ibrahim, Mohamed Kelaney, Maha Michael, Zeinab El-Sayed
      Abstract: Purpose: Following total thyroidectomy of differentiated thyroid carcinoma (DTC), some patients are ablated with radioactive iodine I-131 (RAI). We compare the success of ablation with 30 millicurie (mCi) versus 80 mCi.Methods: We randomized the patients to 30 mCi or 80 mCi RAI after surgery. T1-T3, N0-N1, M0 tumors were included (based on the AJCC 7th edition). Pre-ablation baseline serum thyroglobulin (sTg), and thyroglobulin antibody (Tg Ab) were performed. Six months post-ablation successful thyroid ablation was defined as a negative whole body scan (WBS) and undetectable sTg.Results: Out of 50 patients with DTC, 45 patients fulfilled the eligibility criteria. Total thyroidectomy was performed in 27/ 45 (60%). 26/45 (57.8%) of patients received 30 mCi while 19/45 (42.2%) patients received 80 mCi. The median age was 37 and 36.5 years in the arms 80 and 30 mCi respectively. Papillary carcinoma predominated in 42/45 (93.3%) of patients. T2 tumors predominated in 10/19 (52.6%), and 15/26 (57.7%) of the 80 and 30 mCi arms respectively. According to the American Thyroid Association (ATA) risk classification, all of the patients had low risk disease. Success of ablation was achieved in 15/19 (78.9%), and in 15/26 (57. 7%) of the arms 80 and 30 mCi respectively. No patients developed distant metastases in both arms. The patients who received 80 mCi had longer hospital isolation than the 30 mCi arm (p 0.008). 6/26 (23.1%) patients in the 30 mCi arm were isolated for 2-4 days, whereas all the 80 mCi arm patients were isolated for 3-5 days.Conclusion: Both 80 mCi and 30 mCi RAI have similar success rate in the ablation of thyroid remnant of low risk DTC patients. The low dose is associated with fewer side effects, shorter hospital admission duration, and is less expensive in low risk DTC patients. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Anti-tumor effects of interferon-beta cell therapy in murine model of
           melanoma

    • Authors: Masaki Nakamura, Lisa Kagawa, Norihiro Nakada, Masashi Satoh, Shotaro Maehana, Fumiaki Kojima, Hideki Amano, Yoshiki Murakumo, Kazuya Iwabuchi, Masataka Majima, Hidero Kitasato
      Abstract: Purpose: Recombinant interferon beta (IFN-β) has been used for a treatment of cancers. However, the efficacy of recombinant IFN-β is limited because of its short half-life and side effects. To overcome these problems, we focused on the efficacy of cell-based therapy (cell therapy) using IFN-β-producing cells in the treatment of melanoma.Methods: IFN-β-producing therapeutic cells were constructed by gene transduction using retrovirus vector. Anti-tumor effects of the cell therapy were investigated by a murine melanoma model.Results: IFN-β cell therapy significantly suppressed the proliferation of B16 melanoma in vitro and the growth of B16-derived tumor in vivo, accompanied with the activation of natural killer (NK) cells. IFN-β cell therapy did not show any systemic side-effects concerning hepatic dysfunction and bone marrow suppression.Conclusion: IFN-β cell therapy could be a candidate as a novel cancer treatment. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • What should we know about photon dose calculation algorithms used for
           radiotherapy' Their impact on dose distribution and medical decisions
           based on TCP/NTCP

    • Authors: Abdulhamid Chaikh, Tamizhanban Kumar, Jacques Balosso
      Abstract: The dose calculation algorithms, integrated in a radiotherapy treatment planning system, use different approximations to swiftly compute the dose distributions. Any biological effect is somehow related to the dose delivered to the tissues. Thus, the optimization of treatment planning in radiation oncology requires, as a basis, the most accurate dose calculation to carry out the best possible prediction of the Normal Tissue Complication Probability (NTCP), as well as Tumor Control Probability (TCP). Presently, a number of bio-mathematical models exist to estimate TCP and NTCP from a physical calculated dose using the differential dose volume histogram (dDVH). The purpose of this review is to highlight the link between any change of algorithms and possible significant changes of DVH metrics, TCP, NTCP and even more of estimated Quality-adjusted life years (QALY) based on predicted NTCP. The former algorithms, such as pencil beam convolution (PBC) algorithm with 1D or 3D density correction methods, overestimated the TCP while underestimating NTCP for lung cancer. The magnitude of error depends on the algorithms, the radiobiological models and their assumed radiobiological parameters setting. The over/under estimation of radiotherapy outcomes can reach up to 50% relatively. Presently, the anisotropic analytical algorithm (AAA), collapsed cone convolution algorithm (CCC), Acuros-XB or Monte Carlo are the most recommended algorithms to consistently estimate the TCP/ NTCP outcomes and QALY score, to rank and compare radiotherapy plans, to make a useful medical decision regarding the best plan. This paper points out also that the values of the NTCP radiobiological parameters should be adjusted to each dose calculation algorithm to provide the most accurate estimates. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Notch Signalling as a Therapeutic Target in Cancer

    • Authors: Ioana Martinas, Edward Thomas Parkin
      Abstract: Notch signalling is a conserved developmental pathway involved, inter alia, in cell-fate decision, morphogenesis and tissue patterning. Extensive research has linked this pathways with a variety of malignancies, cancer stem cell renewal, induction of epithelial-to-mesenchymal transition and tumor angiogenesis. These data indicate that Notch can act as both a tumor suppressor and an oncoprotein, depending upon cellular context and identify it as a potential therapeutic target in cancer treatment. This review discusses the implications of Notch in a number of hematologic and solid malignancies and some of the currently available inhibitors developed against this pathway as potential cancer therapeutics. 
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Long term survival after brain metastases from malignant melanoma

    • Authors: Carmen Salvador-Coloma, Joaquín Montalar, Óscar Mauricio Niño, Alejandro Tormo, Jorge Aparicio
      Abstract: We present the case of a 32-year-old patient with malignant melanoma who relapsed with an unresectable brain metastases (BM). He was managed with whole brain radiotherapy (WBRT) and temozolomide chemotherapy. A metabolic positron emission tomography (PET-scan) complete response was achieved. He is living disease-free more than 6 years after the diagnosis of BM. He is now 51 years old and remains asymptomatic and free of disease since then. However, a pronounced residual image still appears on magnetic resonance imaging (MRI) ant PET-scan.
      PubDate: 2016-12-28
      Issue No: Vol. 4 (2016)
       
  • Uncertainties in the relative biological effectiveness of therapeutic
           proton beams associated with bias towards high doses per fraction in
           radiobiological experiments

    • Authors: Oleg N Vassiliev
      Abstract: Most data supporting the widely accepted relative biological effectiveness (RBE) value of 1.1 for therapeutic proton beams are from radiobiological experiments with relatively high doses per fraction. The purpose of this study was to estimate bias in RBE that differences in dose levels between these experiments and proton radiotherapy treatments may cause. The linear quadratic model was applied to calculate, using prior experimental data, RBE variations with dose and a/b ratio for doses delivered in a standard fractionation regimen. The results suggest that the RBE measured at relatively high doses per fraction typical for a radiobiological experiment underestimates the RBE of proton radiotherapy with a standard fractionation. The bias increases with decreasing radiation dose and decreasing a/b ratio, suggesting that, if differences in dose levels are not accounted for, there may be a large underestimation of biological effects in late-responding tissues exposed to low doses of radiation.
      PubDate: 2016-12-26
      Issue No: Vol. 4 (2016)
       
  • A dosimetric dnalysis of flattening-filter-free mode linear
           accelerator-based stereotactic body radiation therapy and HDR
           brachytherapy for prostate cancer

    • Authors: Andrew Thomas Wong, Tejas Telivala, Matthew Worth, David Schwartz, David Schreiber
      Abstract: Purpose: Prior studies have reported that linear accelerator (LINAC)-based stereotactic body radiation therapy (SBRT) plans for prostate cancer are unable to achieve comparable intraprostatic doses to high-dose-rate brachytherapy (HDR).  However, the utilization of flattening-filter-free (FFF) beams provides superior dose distributions compared with flattened beams. The purpose of this study was to test the feasibility of achieving the high intraprostatic doses observed in HDR by utilizing LINAC - based SBRT with FFF beams.Methods: We randomly selected 10 patients with localized prostate cancer previously treated at our institution in 2013. FFF-mode LINAC-based SBRT and simulated HDR (using virtual HDR catheters) plans were generated for each patient. The planning target volume (PTV) V100, V125, V150 and V200 values were compared between the two plans using the two-sided paired samples t-test.Results: Regarding the PTV coverage, the mean V100 was slightly higher for SBRT at 96.47% compared with 94.68% for HDR (p = 0.003). The V125 (61.69% versus 66.51%, p = 0.004) and V200 (15.06% versus 19.66%, p < 0.001) were slightly lower for SBRT. There were no significant differences in V150 between the two plans (47.59% versus 49.8%, p = 0.375). Rectal and bladder dosimetry were also comparable between the two modalities, though the rectal maximum dose was lower in the SBRT plan (99.6% versus 103.66%, p = 0.006) and the dose to 15cc of bladder was lower in the HDR plan (96.34% versus 78.18%, p = 0.005).Conclusion: Utilization of FFF mode LINAC-based SBRT allows for achievable dosimetry that is very similar to high dose rate brachytherapy. Further studies are warranted regarding the safety and efficacy of this modality. 
      PubDate: 2016-12-26
      Issue No: Vol. 4 (2016)
       
  • Dosimetric analysis of 3D-conformal radiotherapy and intensity modulated
           radiotherapy for treatment of advanced stage cervical cancer: A
           comparative study

    • Authors: Gangarapu Sri Krishna, Marella Venkata Ramireddy, Komanduri Ayyangar, Palreddy Yadagiri Reddy
      Abstract: Purpose: The purpose of this study is to analyze the dosimetric parameters of three dimensional conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT) with seven and nine fields (7F-IMRT, 9F-IMRT) in selected advanced stage cervical cancer cases.Methods: Fifteen cases of cervical cancer (IIB to IIIB) were selected for retrospective analysis. All the cases were previously treated with 3DCRT technique with prescribed dose of 50 Gy in 25 fractions.  For this study, plans with seven fields IMRT and nine fields IMRT were generated for all patients following Radiation Therapy Oncology Group (RTOG) guidelines. The plans were compared on the basis of planning target volume (PTV) coverage (dose to 1%, 5%, 95% and 99% of target), maximum dose and mean dose to organs at risk (OARs) and also doses at different volumes of OARs. Apart from this, uniformity index (UI), homogeneity index (HI), conformity index (CI) and dose spillage index (R50%) were also calculated with respect to PTV coverage.Results: The average dose value of PTV coverage for all three techniques were comparable and all the DVH indices for 7field IMRT (UI (1.04±0.01), HI (0.07 ±0.02), CI (0.75±0.03) and R50% (4.47±0.36)) were better than 3DCRT and 9F-IMRT techniques. All OAR doses were significantly reduced in 7F- IMRT compared to 3DCRT and 9F- IMRT. The target volumes ranged from 769.2 ml to 1375.6 ml with average target volume of 1071.9 ml (SD: 205.38 ml).Conclusion: This study showed that significant dose reduction to OARs could be achieved with seven field IMRT plans by maintaining the PTV coverage compared to 3DCRT or 9F- IMRT for treating cervical cancer in advanced stages particularly from IIB to IIIB.
      PubDate: 2016-12-26
      Issue No: Vol. 4 (2016)
       
  • Dose-volume consistency and radiobiological characterization between
           prostate IMRT and VMAT plans

    • Authors: James Chow, Runqing Jiang, Alexander Kiciak
      Abstract: Purpose: Dose-volume consistency of the planning target volume (PTV) and rectum for the prostate intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were evaluated and compared. Dependences of radiobiological parameters of the prostate and rectum on the PTV and rectal volume were also investigated.Methods: From 40 prostate IMRT and 50 VMAT patients treated with the same prescription (78 Gy per 39 fractions) and dose-volume criteria in the inverse planning, the prostate tumour control probability (TCP), rectal equivalent uniform dose (EUD) and rectal normal tissue complication probability (NTCP) were calculated. The dose-volume consistency of the PTV and rectum, demonstrating the variability of dose-volume histogram (DVH) among patients, was defined and calculated as per the deviation between the corresponding and mean DVH.Results: For the IMRT plans, the prostate TCP was found increasing with the PTV with a rate equal to 1.05 × 10-3 % cm-3, which was lower than 1.11 × 10-3 % cm-3 for the VMAT plans. Both the rectal EUD and rectal NTCP were found decreasing with the rectal volume. The decrease rates for the IMRT plans (EUD = 0.47 × 10-3 Gy cm-3 and NTCP = 3.94 × 10-2 % cm-3) were higher than those for the VMAT (EUD = 0.28 × 10-3 Gy cm-3 and NTCP = 2.61 × 10-2 % cm-3).Conclusion: For the dose-volume consistency, small prostate TCP variation could be achieved by decreasing the dose-volume variability among the IMRT and VMAT plans. However, dependences of the rectal EUD and rectal NTCP on the dose-volume variability were not significant. It is concluded that maintaining a good dose-volume consistency in prostate plans can decrease the prostate TCP variation among the IMRT and VMAT patients. However, dose-volume variability is not affected by variations of the rectal EUD and rectal NTCP. 
      PubDate: 2016-12-26
      Issue No: Vol. 4 (2016)
       
  • A phantom study for in-vivo dosimetry of high dose rate brachytherapy
           applicators

    • Authors: Muhammad Asghar Gadhi, Saeed Ahmad Buzdar, Muhammad Arshad, Muhammad Akram, Farooq Aziz, Aziz-Ur Rehman, Shahab Fatmi
      Abstract: Purpose: The aim of the current investigation was to calibrate the diode in-vivo dosimetry (IVD) system for high-dose-rate (HDR) brachytherapy and to design a phantom study for in-vivo dosimetry of HDR brachytherapy applicators.Methods: Gamma Med Plus with Abacus 3.1 treatment planning system (TPS), and diode dosimetry system has been used in this study. Calibration and different correction factors of diode have been measured in water phantom. Treatment simulation, planning of different applicators for esophagus, rectum/vagina and cervix (fletcher & ring), dose delivery and finally in-vivo verification at prescription point using diode in water phantom has been performed.Results: The mean calibration factor for diode for Ir-192 HDR source is 1.256 (N=15) with σ ± 0.0015. The overall average percentage difference between TPS dose and diode dose was 1.87% (σ ± 2.64) for all measurements, 1.86% (σ ± 2.73) for esophagus, 1.86% (σ± 2.94) for rectum/vagina and 1.67% (σ ±2.81) for fletcher and 2.07% (σ ± 2.26) for ring applicators, respectively. These results advocate that the dose calculated by TPS and dose measured using diode for the various clinical situations deliberated here are in good agreement (~2%) at the points of clinical importance.Conclusion: The in-vivo phantom dosimetry study gives both a confidence that the treatments are being delivered as prescribed and enhance the reliability of the HDR brachytherapy treatment. This may be used for acceptance testing/commissioning of new treatment planning system and to validate the new brachytherapy techniques in the clinics. 
      PubDate: 2016-12-04
      Issue No: Vol. 4 (2016)
       
  • Role of Interleukin-18 in Thyroid tumorigenesis

    • Authors: Toral Kobawala, Trupti Trivedi, Kinjal Gajjar, Girish Patel, Nandita Ghosh
      Abstract: Purpose: Although the significance of Interleukin-18 (IL-18) has been studied in pathogenesis of different cancers including, ovarian, gastric, breast, lung carcinoma and melanoma, its role in thyroid cancer- the most common endocrine malignancy has not yet been looked at extensively. Hence, this study intended to examine the role of IL-18 in thyroid tumorigenesis.Methods: Sixty seven patients with benign thyroid diseases and 106 thyroid cancer patients (including 83 papillary, 6 follicular, 9 medullary and 8 anaplastic thyroid carcinoma patients) were enrolled in the study. To accomplish the aim, the circulating levels of IL-18 were estimated by enzyme linked immunosorbent assay (ELISA) from all patients and compared with controls. Further, protein expression of IL-18 was determined from the primary tumors of the patients using immunohistochemistry.Results: It was observed that the circulating levels of IL-18 were significantly higher in all patients: benign thyroid diseases (p = 0.006), papillary (p < 0.001), follicular (p = 0.023), medullary (p = 0.002) and anaplastic thyroid cancer (p < 0.001) than the controls. In addition to this, IL-18 could well discriminate papillary (AUC = 0.627, p =0.008) and anaplastic thyroid carcinoma patients (AUC = 0.777, p = 0.011) from patients with benign thyroid diseases. However, the difference between tumoral protein expression of IL-18 in patients with benign thyroid diseases and thyroid carcinoma was not significant. The Kaplan - Meier survival analysis revealed that neither the circulating nor the tumoral protein expression of IL-18 was the significant predictor of disease free survival (DFS) or overall survival (OS) in papillary thyroid cancer patients.Conclusion: Though not a significant prognosticator, circulating IL-18 may be useful as a differentiating factor in thyroid tumorigenesis and the increase in serum IL-18 levels may be provoked in response to the tumor. Thus, including IL-18 along with the current treatment practice may have a significant role in better management of the disease. However, further exploration of this interleukin is required in a larger series of patients with longer follow up period.
      PubDate: 2016-12-04
      Issue No: Vol. 4 (2016)
       
  • An experimental method to calculate the on-axis dose in small field for
           stereotactic radiotherapy

    • Authors: Talal Abdul-Hadi, Rezart Belshi, Gauthier Bouilhol, Abdulhamid Chaikh, Pascal François
      Abstract: Purpose: The use of small fields in advanced radiotherapy techniques has increased, in particular in stereotactic treatments. However, measuring on-axis dose in such fields is challenging. In this study, we developed an analytic model to accurately estimate the on-axis dose in small fields.Methods: Our study was carried out using 6 MV photon beams from four linear accelerators and with three dosimeters placed in a water tank: EBT3 Gafchromic films, a 31016 PinPoint ionization chamber and a 60017 E diode. The out-of-field leakage factor defined as the ratio of the central axis dose to the off-axis dose was modeled. On-axis doses estimated from out-of-field measurements were compared with the measured ones.Results: The experimental validation of the present method was performed for square and rectangular fields with sizes ranging from 0.5 ⨯ 0.5 cm2 to 10 ⨯ 10 cm2. We found the leakage factor exhibits an exponential decrease independent of the accelerator. This behavior can be integrated in the model to estimate the on-axis dose with an agreement better than 2% compared to EBT3 film measurements at a 10 cm depth and an 8 cm cross-plane off-axis distance.Conclusion: We have developed an analytic model to estimate the on-axis dose in small fields based on the out-of-field leakage measurement. This model can be used to validate dose and output factor measurements.
      PubDate: 2016-10-30
      Issue No: Vol. 4 (2016)
       
 
 
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