Dosimetric analysis of 3D-conformal radiotherapy and intensity modulated radiotherapy for treatment of advanced stage cervical cancer: A comparative study

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

DVH Analysis of Cobalt-60 treatment plans incorporating a recently developed MLC

Purpose: The aim of this investigation was to measure the gain in DVH indices when the recently developed MLC was used for Cobalt-60 treatments.Methods: A prototype multileaf collimator (MLC) that was retrofitted to telecobalt-60 therapy machine was reported and is currently proposed for clinical trials in our institution. Ten patients’ plans that were previously planned through an ECLIPSE® treatment planning system and were treated with open beams from Cobalt-60 machine were imported into Radiation Oncology Planning System [ROPS] and the dose calculations and dose volume histogram (DVH) analysis were performed. The plans were re-planned using the Cobalt-MLC, a feature available in the ROPS planning system. The DVH analysis consisted of conformity index (CI), homogeneity index (HI) and conformation number (CN). The results of this study are presented in this paper. The analysis specifically aimed at measuring the gain in these indices when the MLC was compared with open beams.Results: DVH Comparison of ten sites using open and Cobalt MLC fields showed that the use of MLC results in reduced normal tissue dose, while maintaining the GTV dose. Lower value of CI for normal structures was observed demonstrating the sparing of critical organs when MLC was used. The index HI was studied to show the significance of hot spots outside the PTV. Hot spots were observed even with MLC beams for some cases due to less number of fields.Conclusion: It has been demonstrated through DVH analysis that the use of the recently developed MLC for Cobalt Teletherapy machine results in benefit for the treatment of patients

DVH Analysis of Cobalt-60 treatment plans incorporating a recently developed MLC

Purpose: The aim of this investigation was to measure the gain in DVH indices when the recently developed MLC was used for Cobalt-60 treatments.Methods: A prototype multileaf collimator (MLC) that was retrofitted to telecobalt-60 therapy machine was reported and is currently proposed for clinical trials in our institution. Ten patients’ plans that were previously planned through an ECLIPSE® treatment planning system and were treated with open beams from Cobalt-60 machine were imported into Radiation Oncology Planning System [ROPS] and the dose calculations and dose volume histogram (DVH) analysis were performed. The plans were re-planned using the Cobalt-MLC, a feature available in the ROPS planning system. The DVH analysis consisted of conformity index (CI), homogeneity index (HI) and conformation number (CN). The results of this study are presented in this paper. The analysis specifically aimed at measuring the gain in these indices when the MLC was compared with open beams.Results: DVH Comparison of ten sites using open and Cobalt MLC fields showed that the use of MLC results in reduced normal tissue dose, while maintaining the GTV dose. Lower value of CI for normal structures was observed demonstrating the sparing of critical organs when MLC was used. The index HI was studied to show the significance of hot spots outside the PTV. Hot spots were observed even with MLC beams for some cases due to less number of fields.Conclusion: It has been demonstrated through DVH analysis that the use of the recently developed MLC for Cobalt Teletherapy machine results in benefit for the treatment of patients.</p

2-methoxyestradiol Prevents LNCaP Tumor Development in Nude Mice: Potential Role of G/M Regulatory proteins

Nontoxic naturally occurring metabolite of estrogen namely 2-methoxyestradial (2ME 2 ) found in serum and urine has been shown to be antitumorigenic in various tumor models including the prostate. A recent study conducted in breast cancer cells showed growth stimulatory effect of 2ME 2 when used at low concentrations (10-750 nM). Studies from our laboratory has demonstrated prostate tumor preventive ability of 50 mg/kg 2-ME 2 . In this study we show that concentrations of 2-ME 2 as low as 1 μM is sufficient to inhibit proliferation and induce apoptosis in androgen responsive LNCaP cells. In addition oral administration of doses lower than 50 mg/kg prevented prostate tumor development in LNCaP xenograft model. The observed tumor growth inhibition was associated with induction of apoptosis, increased expression of Wee1 kinase and p34cdc2. In addition administration of 25 mg/kg 2-ME 2 prevented tumor development significantly that is associated with reduction in serum PSA levels