Introduction: The fundamental principle of the Fricke gel dosimeter involves the oxidation of ferric ions upon exposure to radiation. However, a significant limitation of this dosimeter is the post-irradiation diffusion of ferric ions, which can result in the degradation of spatial dose information. Material and Methods: Gels were prepared using 300 bloom gelatin, deionized water, sulfuric acid, ferrous ammonium sulfate, and xylenol orange dye (Sigma-Aldrich). The solution was then poured into 10 ml plastic cuvettes.. The gel samples were refrigerated at various temperatures for 1 to 10 days and irradiated within a water bath environment utilizing a telecobalt unit (Phoenix, Theratronics) employing parallel opposed beams. Spectrophotometric analysis at a wavelength of 585 nm was used to measured optical density changes with dose.. This procedure was repeated across gel formulations prepared under differing pH conditions. Results: The gel's optimum pH value, which was stored for 10 days at 5° C, showed a linear response up to 10 Gy, although the storage time was longer than that of the gels with low (0.3) and high pH (1.3). The auto oxidation rate was determined and found to be less for non-irradiated gel batches stored at 5° C in relation to the gel samples at room temperature and freezing temperature. Conclusion: The dose response of the dosimeter is highly dependent on its pH, composition, alkaline residuals, and pre-irradiation storing conditions.. We observed the optimum pH is 1, at which the dosimeter shows a maximum response. Storing gel samples at 5°C notably reduces the Fe2+ to Fe3+ auto-oxidation rate.

Purpose: A simple planning technique for craniospinal irradiation using Eclipse treatment planning system. Material and methods: In RT treatment planning, base plan optimization feature is used in sequential RT planning by anticipating the dose delivered to organ at risk (OAR) & planning target volume (PTV) in the base plan. In hybrid planning technique, the whole PTV is divided into two parts, Brain PTV & Spine PTV. Spine PTV is overlapped minimum 2-3 cm over the Brain PTV at their junction while creating structures for RT planning. Brain PTV is planned with conventional RT technique & the Spine PTV planned with rapid arc technique (VMAT). In the plan optimization process of spine PTV, first base plan is selected then the optimization parameter is set accordingly as per total prescribed dose of 36 Gy for both the PTVs. The base plan is the dose calculated plan which is incorporated in the rapid arc plan optimization hence the pre-existed doses of Brain PTV & OAR help to understand the plannerfor achieving desired planning objectives during Spine PTV, RT plan optimization. Finally for the dose calculation of Spine PTV RT plan, planner has to copy fields of Brain PTV & paste it in Spine PTV plan and need to calculate dose for these copied fields. The final plan contains a dose calculated of Brain PTV fields and Spine PTV fields termed as hybrid plan. Result: Reduction in the total number of monitor units is observed for the hybrid plan compared to single VMAT plan, which is statistically significant (p<0.05). Conclusion: Present study introduced the hybrid planning technique which can exploit benefits of conventional and modern techniques.

Introduction: The present study demonstrated role of overall treatment time when estimating tumor control probability (TCP) and normal tissue complication probability (NTCP) for moderately hypofractionated and accelerated fractionation schedules in head & neck treatment plans. Repopulation effect in the squamous cell carcinoma is an influencing factor that should be considered when evaluating TCP and NTCP in early responding tissue. This effect can be incorporated by the means of overall treatment time in days. Material and Methods: The proposed study separated in two parts. In the first case, we assumed four moderately hypofractionated schedules for demonstration, including conventional fractionation schedule (CFS) (70Gy/35 #), fractionation schedule 1 (66Gy/30#), fractionation schedule 2 (60Gy/24#) & fractionation schedule 3 (55Gy/20#). Four independent volumetric modulated arc treatment plans were generated at different fractionation schedules for 15 patient’s data set and therefore led to a total of 60 treatment plans. The treatment plan created for CFS is the reference plan for comparison of calculated TCP & NTCP amongst the four plans. The rest three plans for each patient were created simply by changing the dose prescription for FS1, FS2 & FS3, the mean total dose and dose per fraction. In the second scenario, conventional fractionation schedule (66Gy/33# with five fractions per week) compared against accelerated fractionation schedule (66Gy/33# with six fractions per week). The cumulative dose volume histogram for all treatment plans were used for TCP/NTCP estimation by Niemierko EUD, Poisson model and LKB model. The TCP/NTCP calculated in two different way for tumor & oral mucosa of head & neck site. Contrary to the second case, the overall treatment time (OTT) in days not accounted in the first case. Results: It was statistically significant difference (p<0.05) obtained between calculated TCP/NTCP in both moderately hypofractionated and accelerated fractionation schedules. Conclusion: There is significant impact of OTT and it should be considered when evaluating TCP/NTCP for early responding tissue.

This study aimed to evaluate the survival outcomes and identify prognostic factors for patients with oral cavity cancer (OCC) who underwent adjuvant treatment with volumetric arc therapy (VMAT) using simultaneous integrated boost (SIB). Data was collected for post-operated patients of carcinoma of oral cavity who received adjuvant VMAT with SIB between June 2018 and December 2022. The data was entered and analyzed using SPSS software version 20.0. Survival rates were estimated using Kaplan Meier method. To determine survival difference between the groups, log rank test was used. Multivariate analyses were performed with Cox proportional hazard model and p value < 0.05 was considered as significant. A total of 178 patients were included in the study. The median follow-up period was 26 months (range 3–56 months). The 3-year OS, DFS, and LRC rates were 78

Purpose:Development and validation of a simple and convenient computational program in MATLAB environment for estimating the tumor control probability (TCP) and the normal tissue complication probability (NTCP), as a decision support system for routine plan evaluation. Materials and Methods:We developed an in-house software using MATLAB 2016b (Mathworks) for estimating TCP and NTCP named as RBMODELV1. The program contains Niemierko free equivalent uniform dose (EUD) program code provided in authors research article. For rest of radiobiological (RB) models in the software separate coding is performed. The program accepts cumulative dose-volume histogram file in (.txt) format containing two columns dose and volume. A set of two RB parameters were prepared, default and user-dependent in excel sheet named as RBDATA. We cross-validated results of RBMODELV1 software with BioSuite software for Poisson's TCP model and Lyman-Kutcher-Burman (LKB) model. A set of total 20 patient's data of head and neck site took under study and respective TCP and NTCP calculated by all the RB models and compared. Results:This is the first study in which we tried to establish correlation between the mean doses (EUD) received by parallel structure (parotid gland and oral cavity) and predicted percentage of NTCP values. It is found that mean dose in the range of 35-40 Gy for parotid gland can result in more than 50% NTCP predicted by all four RB models. Similarly oral cavity receiving mean dose in the range of 53-58 Gy can results in more than 35% NTCP predicted by all the four models. There is <3% variation observed between TCP calculated by BioSuite and RBMODELV1 software and <4% variation observed between predicted NTCP for parotid gland and oral cavity OAR from LKB model by both the software. Conclusion:We created simple software RBMODELV1 which can be used as a research tool as well as decision support system.

AIM: - The aim of this study is to assess the QOL in breast cancer patients during different stages, mastectomy surgery, chemotherapy, radiation therapy. To evaluate quality of life of females after mastectomy and factors affecting the same in various domain of life MATERIAL AND METHOD:-60 breast cancer patients (mastectomy=20, chemotherapy=20, radiotherapy=20) from May 2019 to Nov 2020. Translated version of a customized questionnaire based on the Royal College of surgeons, quality of life Instrument- Breast cancer patient version (QOL-BC), self-designed questionnaire. Questionnaire is used assess quality of life these patients. Prospective study after whole breast radiation therapy (50Gy plus a 10Gy boost). Patient data collected before beginning of cancer treatment, and at every stage of treatment surgery, chemo and radiation and 3 months after complete treatment. During the interview, we collected information on demographic characteristics, treatment method for breast cancer patient's mastectomy, chemotherapy, and radiotherapy social well-being and quality of life chemotherapy & radiotherapy patients. Statistical analysis performed for the demographic characteristics of social well-being quality of life of mastectomy, chemo therapy and radiotherapy status were summarized using frequency and percentage for categorical variables, means and standard deviation (SD) for continuous variables. Analysis of variance (ANOVA) was used to compare mean of the total QOL scores in three study groups. Data analyses was done using SPSS version 16.0 software. RESULT:- For mastectomy surgery body image, pain, activity daily living, treatment, the mean QOL score coming out to be above the 50 percent of total QOL score, psychological aspect almost 50 percent score and sexual life less than 50 percent score .QOL chemotherapy total score coming out almost 50 percent and radiotherapy less than 50 percent score. CONCLUSION: Adequate social support from family members, friends and neighbors, and higher scores of social well-beings, were associated with signicantly improved quality of life Breast cancer patients.

Purpose: To classify the available plan evaluation indices and compare the dosimetric suitability of these indices. Materials and Methods: Available published plan evaluation indices were categorized. Conformity index (CI) into two groups, one group contains those CI formulas which do not consider critical structure and other group contains those CI formulas which consider planning target volume (PTV) coverage, normal tissue and critical structure sparing simultaneously. Various homogeneity index (HI) formulas extracted from literature. Structure data sets of 25 patients were taken under consideration comprising of various sites. For each patient, two plans were created using Volumetric Arc Therapy technique. First type of plan (Plan-A) were generated considering all tissue objectives for targets and Organ at Risks (OARs) whereas second type of plan (Plan-B) were generated considering only targets tissue objectives and excluding OARs tissue objectives during plan optimization and dose calculation. Planning evaluation parameters were compared between Plan-A and Plan-B. Results: CI calculated by various formulas in two different scenarios presented <2% variation. Any commonly used CI formula failed to differentiate the two different planning situations. On comparison between HI of two different scenario, it is observed that there are four formulas of HI which showed negligible variation but two formulae: S-index and HI (D) showed marginal variation. It is also observed that when OARs are removed from optimization dose homogeneity improved which is specifically pointed by sigma index formula. Conclusion: CI, which has assimilated the presence of OAR in their formulation, shows more reliability in plan evaluation. Sigma index was found to be more efficient formula while evaluating homogeneity of a treatment plan.

The purpose of this study is to introduce and demonstrate a novel graphical method to determine effective bremsstrahlung focal spot size and shape of the therapeutic beam from a linear accelerator. The energy distribution within the beam spot allows in determining effective bremsstrahlung size and shape of beam spot. The transverse and radial dose profiles were measured for a range of field sizes in an isocentric setup. The Length of direct focal region (LDFR) on either side of profiles were determined through the de-convolution of dose profile. The graph plotted for LDFR versus field size helps in determining properties of beam spot. The dimensions of FWHM of effective bremsstrahlung focal spot were found elliptical in nature close to the order of 1 mm. This method allows determination of FWHM of the effective bremsstrahlung focal spot that fairly falls within the range of dimension of FWHM of beamspot published in literature.

PURPOSE: This study is a comparison between revised Manchester Point A and International Commission on Radiation Units and measurements (ICRU) 89 report-recommended Point A absorbed-dose reporting in intracavitary brachytherapy for patients with cervical carcinoma.METHODS AND MATERIALS: The retrospective dosimetric study is based on the data of 32 patients with cervical carcinoma treated with high-dose-rate brachytherapy. Patients received 21 Gy in three fractions (7.0 Gy X three fractions) to Point A (A(flange), revised Manchester definition). All the patients were replanned with a new Point A (A(icru89)) defined on CT images as per the American Brachytherapy Society/ICRU-89. The data collected were compared with the data obtained from Point A (A(flange)).RESULTS: When using the A(flange) plan normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 820.79 +/- 207.47 cGy, 654.66 +/- 152.69 cGy, and 588.91 +/- 136.35 cGy, respectively. Likewise, when using the ICRU-89 Point A(icru89) normalization method, the mean dose of 0.1 cc, 1 cc, and 2 cc bladder volumes was 869.30 +/- 224.67 cGy, 693.24 +/- 166.20 cGy, and 616.61 +/- 150.32 cGy, respectively. For the rectum, Point A(flange) normalization plans, the mean dose of 0.1 cc, 1 cc, and 2 cc volumes was 589.37 +/- 163.26 cGy, 487.51 +/- 126.03 cGy, and 442.70 +/- 111.43 cGy, respectively. Likewise, using the A(icru89) plan, the mean 0.1 cc, 1 cc, and 2 cc rectum volume was 625.07 +/- 171.31 cGy, 517.50 +/- 131.05 cGy, 464.94 +/- 121.81 cGy, respectively. The statistical mean difference of Total Reference Air Kerma rate, V-100 (cc), bladder, rectum and sigmoid, was found significant.CONCLUSIONS: It has been found that the position of revised Manchester (A(flange)) and ICRU-89 Point A does not match on CT images/radiograph, which resulted in variation in doses to the tumor, V-100 (cc), organ at risk, and Total Reference Air Kerma. (c) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Purpose. - To explore the possibility of revising the spinal cord tolerance dose in Simultaneously Integrated Boost (SIB) intensity modulated treatment plan of locally advanced head and neck (H&N) cancer and assessment of achieved planning gain due to the revision. In SIB regimen, the Organ at Risk (OARs) tolerance dose is equally distributed throughout the treatment. Clinicians have usually considered the spinal cord tolerance to be the same as in conventional technique. However, in SIB fractionation regimen with intensity modulation treatment, the spinal cord may receive a physical dose of 45 Gy, with much lesser dose per fraction than 2 Gy per fraction. So when the dose of spinal cord is distributed throughout the treatment, the tolerance dose limit of physical dose can be considered higher than the usual conventional dose limits. In this study, an attempt has been made to explore the possibilities of dose escalation and treatment planning benefits while exploiting this "Window of Opportunity (WoO)" of increase in spinal cord and Planning Risk Volume (PRV) spinal cord tolerance dose. Material and methods. - A total of 12 patients CT data set along with approved structure set of H&N cancer used for treatment planning in. Three independent SIB VMAT plans named as SPC, SPR and SPDE were generated for the 12 patients. First plan (SPC) was generated by considering standard spinal cord tissue constraint of maximum dose of 45 Gy and PRV spinal cord maximum dose 50 Gy as per QUANTEC summary and second plan (SPR) was generated considering spinal cord tissue constraint of maximum dose 52.50 Gy and PRV spinal cord maximum dose 56.35 Gy while optimization and dose calculation. The objectives for rest of the Organ at Risk (OAR) were kept same in both the plans during optimization and dose calculation. The SPC plan was copied for creation of third plan (SPDE) in which dose was escalated by increasing dose per fraction for target volumes such that dose to spinal cord reached a maximum dose of 52.50 Gy and PRV spinal cord maximum dose of 56.35 Gy. In this plan there have been changes to only dose per fraction, however dose optimization and dose calculation have not been performed. Radiobiological parameters TCP and NTCP were also calculated by using indigenously developed software. Results. - Considering the increase of spinal cord tolerance dose as "window of opportunity", a sufficient escalation in physical dose, Biological Effective Dose (BED) and Tumor Control Probability (TCP) was observed for all target volumes with acceptable level of NTCP values. Conclusion. - Sufficient dose escalation and increased in TCP for target volumes or effective planning benefits can be achieved by revising the spinal cord tolerance dose in intensity modulated SIB treatment of locally advanced H&N cancers. (C) 2020 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

Objective Pretreatment imaging plays a crucial role in determining geometric positional uncertainty of the patient during radiotherapy. Our purpose is to investigate the effect of frequent pretreatment imaging protocol (scenario) on actual dose delivery in radiotherapy. This paper presents a critical analysis of frequent imaging protocol with respect to Idealized daily imaging protocol (IDIP). Methods and materials Retrospective patients of Ca-carcinoma cervix, Ca-buccal mucosa, Ca-tongue treated with intensity-modulated radiation therapy (IMRT) undergoing daily cone beam computed tomography (CBCT) imaging protocol was selected for this study. Every treated fraction of these patients was simulated considering its daily geometrical setup uncertainties occurred. Indirect evaluation of virtual treatment plans was conducted in the treatment planning system (TPS) for 3 days a week, 2 days a week, and 1 day a week frequency imaging protocols. Results obtained from these frequent imaging protocols were compared with IDIP. Result Deviation between predicted and delivered dose found increasing with decreasing frequency of imaging. Significant deviations were observed in all the estimated plan quality parameters for patients treated with frequent imaging protocols and IDIP. Deviations were found more in case of pelvis sites than head and neck sites. Conclusion This study plays a vital role in establishing optimum pretreatment imaging protocols in busy clinics. Three days a week imaging protocol is the best suit protocol found with minimal deviation and ample implementation feasibility. This study proposed an opinion pertaining to the revision of setup margin formula in order to accommodate variation due to imaging techniques and frequency of imaging attempted during radiotherapy.

AIM:A systemic review and analysis of evolution journey of indices, such as conformity index (CI), homogeneity index (HI) and gradient index (GI), described in the literature.BACKGROUND:Modern radiotherapy techniques like VMAT, SRS and SBRT produce highly conformal plans and provide better critical structure and normal tissue sparing. These treatment techniques can generate a number of competitive plans for the same patients with different dose distributions. Therefore, indices like CI, HI and GI serve as complementary tools in addition to visual slice by slice isodose verification while plan evaluation. Reliability and accuracy of these indices have been tested in the past and found shortcomings and benefits when compared to one another.MATERIAL AND METHODS:Potentially relevant studies published after 1993 were identified through a pubmed and web of science search using words "conformity index", "Homogeneity index", "Gradient index"," Stereotactic radiosurgery"," stereotactic Body radiotherapy" "complexity metrics" and "plan evaluation index". Combinations of words "plan evaluation index conformity index" were also searched as were bibliographies of downloaded papers.RESULTS AND CONCLUSIONS:Mathematical definitions of plan evaluation indices modified with time. CI definitions presented by various authors tested at their own and could not be generalized. Those mathematical definitions of CI which take into account OAR sparing grant more confidence in plan evaluation. Gradient index emerged as a significant plan evaluation index in addition to CI whereas homogeneity index losing its credibility. Biological index base plan evaluation is becoming popular and may replace or alter the role of dosimetrical indices.

Aim: Objective of present study is to determine optimum value of DLG and its validation prior to being incorporated in TPS for Varian TrueBeam (TM) millennium 120 leaves MLC. Background: Partial transmission through the rounded leaf ends of the Multi Leaf Collimator(MLC) causes a conflict between the edges of the light field and radiation field. Parameter account for this partial transmission is called Dosimetric Leaf Gap (DLG). The complex high precession technique, such as Intensity Modulated Radiation Therapy (IMRT), entails the modeling of optimum value of DLG inside Eclipse Treatment Planning System (TPS) for precise dose calculation. Materials and methods: Distinct synchronized uniformed extension of sweeping dynamic MLC leaf gap fields created by Varian MLC shaper software were use to determine DLG. DLG measurements performed with both 0.13 cc semi-flex ionization chamber and 2D-Array I-Matrix were used to validate the DLG; similarly, values of DLG from TPS were estimated from predicted dose. Similar mathematical approaches were employed to determine DLG from delivered and TPS predicted dose. DLG determined from delivered dose measured with both ionization chamber (DLG(Ion)) and I-Matrix (DLGI-Matrix) compared with DLG estimate from TPS predicted dose (DLG(TPS)). Measurements were carried out for all available 6MV, 10MV, 15MV, 6MVFFF and 10MVFFF beam energies. Results: Maximum and minimum DLG deviation between measured and TPS calculated DLG was found to be 0.2 mm and 0.1 mm, respectively. Both of the measured DLGs (DLG(Ion) and DLG(I-Matrix)) were found to be in a very good agreement with estimated DLG from TPS (DLGTPS). Conclusions: Proposed method proved to be helpful in verifying and validating the DLG value prior to its clinical implementation in TPS. (C) 2017 Greater Poland Cancer Centre. Published by Elsevier Sp. z o.o. All rights reserved.

Purpose: The purpose of the study was to present the quantitative and qualitative evaluation of newly incorporated photon optimizer (PO) versus previously was used independent dose volume optimizer (DVO) for intensity modulated radiation therapy (IMRT) and progressive resolution optimizer (PRO) for Rapid-arc/ volumetric modulated arc therapy (VMAT) in version 13.5 of Eclipse treatment planning system (ETPS). Methods: We accomplished this study with the help of cylindrical virtual phantom created in the ETPS. Six individual phantoms study sets (PSS) were generated and different material density value was assigned in order to evaluate the behavior optimizers in the presence of tissue heterogeneity. Several independent plans were generated for IMRT and Rapid-arc by changing optimizer module PO, DVO, and PRO for 6 MV, 15 MV flattened beam and 6 MV-flattening filter free (FFF) beam. Results: The self-governing evaluations of PO versus DVO for IMRT plan and PO versus PRO for Rapid-arc/VMAT plans were performed. We estimated and compared various distinct parameters such as maximum dose, minimum dose, mean dose, conformity index (CI), quality index (QI), homogeneity index (HI), integral plan monitor unit (MU) and dose volume histogram (DVH). The percentages of the average variation over all PSS and beam energy between PO versus DVO optimized plan quality parameters such as planning target volume (PTV) maximum, minimum, mean doses, CI, QI and HI were 0.23%, 1.67%, 0.09%, 20.4%, 0.77% and 0.52% , respectively, whereas for PO versus PRO were 1.18%, 3.38%, 0.19%, 8.11%, 2.78%, and 1.28%, respectively. Conclusion: The results presented in this study showed that PO generates plans with better quality in shorter time compared to DVO and PRO for both IMRT and Rapid-arc/VMAT, respectively.

Motive of the study is to present quantitative and qualitative analysis and comparison of beam data measurement with FF (flattening filter) and FFF (flattening filter free) beam in a Varian TrueBeamTM Medical Linear Accelerator. Critique of beam characterization and evolution of dosimetric properties for 6 MV, 10 MV, 15 MV FF beam and 6 MVFFF, 10 MVFFF FFF beam has been carried out. We performed the comparison of photon beam data for two standard FF photon energy 6 MV, 10 MV verses 6 MVFFF, and 10 MVFFF FFF beam. Determination and comparison of parameter involved PDD (Percentage depth dose), Depth dose profile, Symmetry, Flatness, Quality index, Relative output factor, Penumbra, Transmission factor, DLG (Dosimetric leaf gap), in addition to degree of Un-flatness and off-axis ratio of FFF beam. Outcomes of presenting study had shown that change of various parameters such as Percentage depth dose curves, Shape of the depth dose profile, Transmission, Value of quality index and significant rise in surface dose for FFF in comparison with FF beam. Differences in the output factor at lower and higher field sizes for FFF beam compared to that of FF beam were found. The maximum output factor deviation between 6 MV and 6 MVFFF was found to be 4.55%, whereas in 10 MV and 10 MVFFF was 5.71%. Beam quality TPR20/10 for FFF beam was found to be lesser in magnitude, 5.42% for 6 MVFFF whereas 4.50% for 10 MVFFF compared to 6 MV and 10 MV FF beam respectively. Jaw transmission and interleaf leakage for FFF beam were found to be lesser than FF beam. Also DLG for FFF beam was found to be lesser in magnitude comparable to that of flattened beam. This study is mainly inclined towards evaluation and comparison of the FF and FFF beam. It has been observed that, the outcome of a commissioning beam data generation fully complies with vendor specification and published literature.