Challapalli Srinivas

• Doctor of Philosophy
• Professor at Manipal Academy of Higher Education

Goal of the present study was to develop and build a phantom that replicates the air gaps under a gel bolus and to estimate the surface dose (Dsurf) under normal incidence with a 6 MV photon beam. For this, an acrylic phantom with 10 plates, each including five open slots (one in the centre and four off axis) with a size of 2 cm × 2 cm at depths of...

Background/Aim To examine the clinical correlation of p16 expression with Epithelial–Mesenchymal Transition (EMT) markers and lymphatic invasion in OPSCC patients in terms of clinical status at presentation, subsequent progression, and survival. Methods Tissue blocks of biopsy-proven Oropharyngeal Squamous Cell Carcinoma were subjected to Immunohi...

Background Cervical cancer poses a significant public health challenge, particularly in low and middle-income countries. Despite advancements in treatment, the disease remains a leading cause of cancer-related deaths among women globally. Chemoradiation utilizing cisplatin has been the cornerstone therapy for locally advanced cervical cancer. Progn...

Introduction: Synovial sarcoma is a rare and aggressive soft-tissue sarcoma that often presents in young adults but can occur at any age. It typically affects the extremities but can also be found in the trunk or head and neck. Characterized by the chromosomal translocation T (X; 18) (P11; Q11) and SYT-SSX gene fusion, the diagnosis and management...

Background: Cervical cancer poses a significant public health challenge, particularly in low- and middle-income countries. Despite advancements in treatment, the disease remains a leading cause of cancer-related deaths among women globally. Chemoradiation utilizing cisplatin has been the cornerstone therapy for locally advanced cervical cancer. Pro...

Purpose: Cervical cancer is a significant global health issue affecting approximately 600,000 women each year. This study aimed to address the knowledge gaps surrounding the influence of treatment time parameters, including the duration of external beam radiotherapy (EBRT) to brachytherapy and overall treatment duration, on early recurrences.Materi...

Background High dose rate (HDR) image-guided brachytherapy with Cobalt-60 isotope is a relatively recent approach. The aim of the study is to evaluate the clinical and dosimetric parameters in terms of tumour response, bladder, and rectal toxicity in patients undergoing Co-60 HDR brachytherapy. Materials and Method All patients were initially trea...

There has been growing interest in the use of epidermal growth factor receptor inhibitors in various cancers. The study was conducted to evaluate the efficacy and safety of gefitinib as a monotherapy in patients with recurrent or metastatic cervical cancer. Patients with cervical carcinoma who experienced locoregional recurrence or distant metastas...

A BSTRACT Introduction Breast cancer is the most common cancer among women in urban areas in India, which is treated with external beam radiotherapy as a part of a multimodality treatment approach. Delivering external beam radiation therapy to the chest wall and nodal basins is challenging because of the anatomical morphology of the chest wall as...

Purpose: Geographic access to medical care varies for nearly every specialty in India. Given the special nature of its treatments, which sometimes necessitate numerous visits over a lengthy period, and the substantial-high fixed cost infrastructure requirements for radiation facilities, radiation oncology is particularly prone to regional inequiti...

Background: To develop a dosimetric tool to estimate the dose delivered in the presence of air pockets with EBT3 film while simulating the conditions of vaginal vault brachytherapy (VVBT) with 3.0 diameter cylindrical applicator at a prescription dose distance of 5mm from the surface of it. Materials and method: Six acrylic plates (10 cm x 10 cm...

Background: To assess and compare the local control and toxicities between HDR Intracavitary Brachytherapy with 7.5 Gy and 9 Gy per fraction after EBRT in treatment of carcinoma cervix. Methodology: A total of 180 patients were randomly assigned to 2 arms. Arm A received HDR intracavitary brachytherapy with a dose of 7.5 Gy per fraction, 1 fract...

Background: A semiconductor rectal probe was used to compare planned and measured rectal doses during Co-60 high dose rate (HDR) CT-based intracavitary brachytherapy applications (ICBT) of cervical cancer. Materials and methods: A total of 22 HDR brachytherapy applications were included from 11 patients who were first treated with EBRT to the wh...

Background: Aim of this study is to evaluate the efficacy of inhomogeneity corrections calculated by radiotherapy treatment planning system (TPS) using various densities of materials. Materials and methods: Gammex Computed tomography electron density inserts (EDI's; 14 no's) were used to generate the CT to ED curve with high speed GE CT scanner...

Background: The aim of this study is to design and fabricate a thorax phantom with irregularly shaped trapezoidal slots across the left side of the chest wall, allowing for the creation of unwanted air gaps under the bolus. Method: Surface dose (Dsurf) measurements were made with Gaf Chromic EBT3 films at air gaps (0.0, 5.0, 10.0 and 15.0 mm) un...

Aim: A tissue-equivalent bolus of sufficient thickness is used to overcome build up effect to the chest wall region of postmastectomy radiotherapy (PMRT) patients with tangential technique till Radiation Therapy Oncology Group (RTOG) Grade 2 (dry desquamation) skin reaction is observed. The aim of this study is to optimize surface dose delivered t...

The aim of this study was to design and fabricate a thorax phantom to quantify the radiation doses to the region of the chest wall (with 3 ionization chambers), the organ at risk (OAR) (lung), and the surface using radiochromic films (EBT3) for three different 3D CRT treatment planning techniques. Anthropomorphic phantoms are one of the best tools...

EVWUDFW 7HFKQLFDO 1RWH 1 1 In some clinical radiation oncology treatments involving megavoltage (MV) photon beam, it is important to use tissue-equivalent material (bolus) on treatment surface to enhance the DFH GR H) if the tumor or fungating lymph node extends upto the skin. Precise measurement of "D " will provide useful information for clinical...

Technical Note

Purpose: The aim of this study is to estimate delivered radiation doses inside planning tumor volume (PTV) using the in vivo (mid-plane dose) measurement and transit measurement methods in gynecological malignancy patients undergoing three-dimensional conformal radiotherapy (3DCRT) using calibrated ionization chambers. Materials and methods: Six...

Objective: This study presents the dosimetric data taken with radiochromic EBT3 film with brass mesh bolus using solid water and semi-breast phantoms, and its clinical implementation to analyze the surface dose estimates to the chest wall in postmastectomy radiotherapy (PMRT) patients. Materials and Methods: Water-equivalent thickness of brass bolu...

Objective: This study presents a method to estimate midplane dose (Diso, transit) in vivo from transit signal (St) measured with thimble ionization chamber in cancer of the middle-third esophagus patients treated with three-dimensional radiotherapy (RT). This detector is positioned at the level of electronic portal imaging device in the gantry of...

Kasturi D. Quality assurance of simultaneous treatment of two targets in pelvic region planned with single isocenter using three dimensional conformal radiotherapy (3DCRT) technique. Int J Cancer Ther Oncol 2015; 3(3):3315. Abstract Purpose: The purpose of this study was to conduct quality assurance of a three dimensional conformal radiotherapy (3D...

This study aims at determining the dose of X-ray delivered through linear accelerator (LINIAC) that results in the 50 % survival of animals after an observation period of 30 days, following exposure to whole body irradiation in rat model. Animals were exposed to several doses of radiation (2, 4, 6, 8, 10 Gy) after which they were monitored for surv...

External beam radiotherapy (EBRT) for carcinoma of uterine cervix is a basic line of treatment with three dimensional conformal radiotherapy (3DCRT) in large number of patients. There is need for an established method for verification dosimetry. We tried to document absorbed doses in a group of carcinoma cervix patients by inserting a 0.6 cc Farmer...

Purpose: Tissue obliquity is a common problem in conventional radiotherapy to head and neck region. This results in generation of hot spots and non‐uniformity of dose in the planned treatment volumes. Ellis compensators made of non divergent aluminum metal rods have been suggested. The purpose of this study is to develop a divergent wax based tissu...

Purpose: Designing a wedge shaped midline block (WMLB) for teletherapy treatments in early cervical cancers, its dosimetric verification and clinical implementation. Methods: The method of designing a WMLB is discussed based on the dose distribution in coronal plane obtained from treatment planning system (TPS) for manual afterloading intracavitary...

To report our experience of stereotactic radiosurgery (SRS) in consecutively treated patients with arteriovenous malformations (AVMs). Of the 87 patients, 23 patients qualified and were treated with SRS as per predefined protocol according to AVM size, location, neurological status, prior bleeding, and the AVM score. All had Spletzer-Martin grade I...

The spent ion exchange resin poses a disposal problem. A novel process, dissolution followed by wet oxidation (WO), for mineralization of the cation exchange resin (gel type) was studied by using homogeneous CuSO4 as the catalyst. The waste obtained after copper catalyzed dissolution of ion exchange resin by H2O2 was then further treated by wet oxi...

Medulloblastoma is the most common malignant brain tumor of childhood, with a propensity for neuraxial spread via the cerebrospinal fluid. However, systemic metastases can occur in a small minority of patients. Very rarely such metastases can involve the mandible and present with intra-oral swelling. One such occurrence in a patient with medullobla...

A hybrid process of Fenton dissolution followed by sonication and wet air oxidation (WAO), has been demonstrated to mineralize strongly basic anion exchange resin (gel type). The solid anion exchange resin beads could be dissolved in water by Fenton process wherein the copper-catalyzed hydrogen peroxide (H2O2) reaction makes the resin hydrophilic b...

Haemangiopericytomas of central nervous system (CNS) were first defined as a separate entity in 1942. Previously they were either considered to be a histological variant of an angioblastic meningioma or a distinctive mesenchymal neoplasm. Most commonly they are located in parasagittal and falcine region. Tumours in the sellar/parasellar location ar...

Head and neck cancer management has undergone several paradigm shifts for several relevant reasons. From the dismal experience with the use of radiotherapy as the sole modality in the treatment of this group of patients with advanced disease, radiotherapy has been evaluated as an adjuvant for the same group of patients who had undergone successful...

This paper deals with the treatment method for the management of spent solvents of reprocessing origin (30% tri-n-butyl phosphate in n-dodecane) using the ‘alkaline hydrolysis process’. The consolidated work reported herein has established total conversion of TBP to aqueous soluble reaction products and transfer of near total radioactivity associat...

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process f...

A b s t r a c t The paper presents the feasibility studies on wet air oxidation studies being carried out using the dissolved resin feed having COD value upto 50000 ppm on pilot scale set-up under a pressure upto 20 bars for various durations. This paper also presents comparison of various industrial practices being adopted for treatment of spent r...