Publications by authors named "Rimpa Basu Achari"

8 Publications

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Setting up a lung stereotactic body radiotherapy service in a tertiary center in Eastern India: The process, quality assurance, and early experience.

J Cancer Res Ther 2020 Jul-Sep;16(4):888-899

Department of Radiation Oncology, Tata Medical Center, Kolkata, West Bengal, India.

Context: Stereotactic body radiotherapy (SBRT) is increasingly being used for early-stage lung cancer and lung oligometastases.

Aims: To report our experience of setting up lung SBRT and early clinical outcomes.

Settings And Design: This was a retrospective, interventional, cohort study.

Subjects And Methods: Patients were identified from multidisciplinary tumor board meetings. They underwent four-dimensional computed tomography-based planning. The ROSEL trial protocol, the Radiation Therapy Oncology Group (RTOG) 0236, and the UK-Stereotactic Ablative Body Radiotherapy Consortium guidelines were used for target volume and organs-at-risks (OARs) delineation, dosimetry, and plan quality assessment. Each SBRT plan underwent patient-specific quality assurance (QA). Daily online image guidance using KVCT or MVCT was done to ensure accurate treatment delivery.

Statistical Analysis Used: Microsoft Excel 2010 was used for data analysis.

Results: Fifteen patients were treated to one or more lung tumors. One patient received helical tomotherapy in view of bilateral lung oligometastases at similar axial levels. All the remaining patients received volumetric modulated arc therapy (VMAT)-based treatment. The prescription dose varied from 40 to 60 Gy in 5-8 fractions with alternate-day treatment. The mean and median lung V20 was 5.24% and 5.16%, respectively (range, 1.66%-9.10%). The mean and median conformity indexes were 1.02 and 1.06, respectively (range, 0.70-1.18). After a median follow-up of 17 months, the locoregional control rate was 93.3%.

Conclusions: SBRT was implemented using careful evaluation of OAR dose constraints, dosimetric accuracy and plan quality, patient-specific QA, and online image guidance for accurate treatment delivery. It was safe and effective for early-stage nonsmall cell lung cancer and lung metastases. Prospective data were collected to audit our outcomes.
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November 2020

De-Identification of Radiomics Data Retaining Longitudinal Temporal Information.

J Med Syst 2020 Apr 2;44(5):99. Epub 2020 Apr 2.

CSE, IIT Kharagpur, Kharagpur, India.

We propose a de-identification system which runs in a standalone mode. The system takes care of the de-identification of radiation oncology patient's clinical and annotated imaging data including RTSTRUCT, RTPLAN, and RTDOSE. The clinical data consists of diagnosis, stages, outcome, and treatment information of the patient. The imaging data could be the diagnostic, therapy planning, and verification images. Archival of the longitudinal radiation oncology verification images like cone beam CT scans along with the initial imaging and clinical data are preserved in the process. During the de-identification, the system keeps the reference of original data identity in encrypted form. These could be useful for the re-identification if necessary.
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April 2020

Challenges in the management of localized intracranial ependymoma in children: Experience from a referral oncology center in Eastern India.

Pediatr Hematol Oncol 2018 Aug - Sep;35(5-6):369-372. Epub 2019 Jan 20.

a Departments of Paediatric Haematology-Oncology , Tata Medical Centre , Kolkata.

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March 2019

Development and validation of a decision support tool to select IMRT as radiotherapy treatment planning modality for patients with locoregionally advanced non-small cell lung cancers (NSCLC).

Br J Radiol 2019 Feb 9;92(1094):20180431. Epub 2018 Nov 9.

1 Department of Radiation Oncology, Tata Medical Center , Rajarhat, Kolkata , India.

Objective:: Radiation planning for locally-advanced non-small cell lung cancer (NSCLC) can be time-consuming and iterative. Many cases cannot be planned satisfactorily using multisegment three-dimensional conformal radiotherapy (3DCRT). We sought to develop and validate a predictive model which could estimate the probability that acceptable target volume coverage would need intensity modulated radiotherapy (IMRT).

Methods:: Variables related to the planning target volume (PTV) and topography were identified heuristically. These included the PTV, it's craniocaudal extent, the ratio of PTV to total lung volume, distance of the centroid of the PTV from the spinal canal, and the extent PTV crossed the midline. Metrics were chosen such that they could be measured objectively, quickly and reproducibly. A logistic regression model was trained and validated on 202 patients with NSCLC. A group of patients who had both complex 3DCRT and IMRT planned was then used to derive the utility of the use of such a model in the clinic based on the time taken for planning such complex 3DCRT.

Results:: Of the 202 patients, 93 received IMRT, as they had larger volumes crossing midline. The final model showed a good rank discrimination (Harrell's C-index 0.84) and low calibration error (mean absolute error of 0.014). Predictive accuracy in an external dataset was 92%. The final model was presented as a nomogram. Using this model, the dosimetrist can save a median planning time of 168 min per case.

Conclusion:: We developed and validated a data-driven, decision aid which can reproducibly determine the best planning technique for locally-advanced NSCLC.

Advances In Knowledge:: Our validated, data-driven decision aid can help the planner to determine the need for IMRT in locally advanced NSCLC saving significant planning time in the process.
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February 2019

Resource requirements and reduction in cardiac mortality from deep inspiration breath hold (DIBH) radiation therapy for left sided breast cancer patients: A prospective service development analysis.

Pract Radiat Oncol 2018 Nov - Dec;8(6):382-387. Epub 2018 Mar 21.

Department of Surgical Oncology, Tata Medical Center, Newtown, Kolkata, West Bengal.

Introduction: Use of deep inspiration breath hold (DIBH) radiation therapy may reduce long-term cardiac mortality. The resource and time commitments associated with DIBH are impediments to its widespread adoption. We report the dosimetric benefits, workforce requirements, and potential reduction in cardiac mortality when DIBH is used for left-sided breast cancers.

Methods And Materials: Data regarding the time consumed for planning and treating 50 patients with left-sided breast cancer with DIBH and 20 patients treated with free breathing (FB) radiation therapy were compiled prospectively for all personnel (regarding person-hours [PH]). A second plan was generated for all DIBH patients in the FB planning scan, which was then compared with the DIBH plan. Mortality reduction from use of DIBH was calculated using the years of life lost resulting from ischemic heart disease for Indians and the postulated reduction in risk of major cardiac events resulting from reduced cardiac dose.

Results: The median reduction in mean heart dose between the DIBH and FB plans was 166.7 cGy (interquartile range, 62.7-257.4). An extra 6.76 PH were required when implementing DIBH as compared with FB treatments. Approximately 3.57 PH were necessary per Gy of reduction in mean heart dose. The excess years of life lost from ischemic heart disease if DIBH was not done in was 0.95 per 100 patients, which translates into a saving of 12.8 hours of life saved per PH of work required for implementing DIBH. DIBH was cost effective with cost for implementation of DIBH for all left-sided breast cancers at 2.3 times the annual per capita gross domestic product.

Conclusion: Although routine implementation of DIBH requires significant resource commitments, it seems to be worthwhile regarding the projected reductions in cardiac mortality.
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January 2019

TP53 Mutation, MYCN Amplification, and Large Cell/Anaplastic Histology in Medulloblastoma.

Indian J Pediatr 2018 08 15;85(8):684-685. Epub 2017 Nov 15.

Department of Radiation Oncology, Tata Medical Centre, Kolkata, India.

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August 2018

NK/T Cell Lymphoma: A Tertiary Centre Experience.

Indian J Hematol Blood Transfus 2017 Mar 21;33(1):69-73. Epub 2016 Apr 21.

Department of Clinical Haematology, Tata Medical Center, Kolkata, India.

Extranodal NK/T-cell lymphoma (ENKTL), nasal type, is a rare type of non-Hodgkin lymphoma that is commonly seen in East Asian countries and is associated with Epstein-Barr virus infection. This is a retrospective study where we describe nine cases of ENKTL; nasal type diagnosed and treated at our center over a period of 2 years. These cases were analyzed retrospectively for clinical presentation (age, sex, site of involvement), immunophenotype, treatment, response and toxicity profile. Sino-nasal symptoms (blocked nose, headache, epistaxis, regurgitation) were the most common presenting complaints (n = 8). Almost 67 % (n = 6/9) of the cases were referred from Bhutan. Necrosis and angiocentricity were the commonest histological features. Depending on the stage of the disease patient were initially treated with chemotherapy (SMILE/CHOP) and Radiotherapy (IFRT). We describe our experience of management of ENKTL, where we observe that Bhutan could be endemic region for this rare tumour.
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March 2017