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Agarwal JP, Krishnatry R, Panda G, Pathak R, Vartak C, Kinhikar RA, James S, Khobrekar SV, Shrivastava SK, D'Cruz AK, Deshpande DD. An Audit for Radiotherapy Planning and Treatment Errors From a Low-Middle-Income Country Centre. Clin Oncol (R Coll Radiol) 2018; 31:e67-e74. [PMID: 30322681 DOI: 10.1016/j.clon.2018.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 10/28/2022]
Abstract
AIMS To report the findings of an audit for radiotherapy errors from a low-middle-income country (LMICs) centre. This would serve as baseline data for radiotherapy error rates, their severity and causes, in such centres where modern error reporting and learning processes still do not exist. MATERIALS AND METHODS A planned cross-sectional weekly audit of electronic radiotherapy charts at the radiotherapy planning and delivery step for all patients treated with curative intent was conducted. Detailed analysis was carried out to determine the step of origin of error, time and contributing factors. They were graded as per indigenous institutional (TMC) radiotherapy error grading (TREG) system and the contributing factors identified were prioritised using the product of frequency, severity and ease of detection. RESULTS In total, 1005 consecutive radically treated patients' charts were audited, 67 radiotherapy errors affecting 60 patients, including 42 incidents and 25 near-misses were identified. Transcriptional errors (29%) were the most common type. Most errors occurred at the time of treatment planning (59.7%), with "plan information transfer to the radiation oncology information system" being the most frequently affected sub-step of the radiotherapy process (47.8%). More errors were noted at cobalt units (52/67; 77.6%) than at linear accelerators. Trend analysis showed an increased number of radiotherapy incidents on Fridays and near-misses on Mondays. Trend for increased radiotherapy errors noted in the evening over other shifts. On severity grading, most of the errors (54/60; 90%) were clinically insignificant (grade I/II). Inadequacies and non-adherence towards standard operating procedures, poor documentation and lack of continuing education were the three most prominent causes. CONCLUSION Preliminary data suggest a vulnerability of LMIC set-up to radiotherapy errors and emphasises the need for the development of longitudinal prospective processes, such as voluntary reporting and a continued education system, to ensure robust and comprehensive safe practises on par with centres in developed countries.
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Affiliation(s)
- J P Agarwal
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - R Krishnatry
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India.
| | - G Panda
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - R Pathak
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - C Vartak
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - R A Kinhikar
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India; Department of Medical Physics, Tata Memorial Center, Parel, Mumbai, India
| | - S James
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - S V Khobrekar
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India; Tata Memorial Hospital, Parel, Mumbai, India
| | - S K Shrivastava
- Department of Radiation Oncology, Tata Memorial Centre, Parel, Mumbai, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India
| | - A K D'Cruz
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India; Tata Memorial Hospital, Parel, Mumbai, India
| | - D D Deshpande
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, India; Department of Medical Physics, Tata Memorial Center, Parel, Mumbai, India
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Gopalakrishna A, Suryanarayana SV, Naik H, Nayak BK, Patil BJ, Devraju S, Upreti RR, Kinhikar R, Deshpande DD, Maletha P, Kamaldeep, Banerjee S, Saxena A. Production of 99Mo and 64Cu in a mixed field of photons and neutrons in a clinical electron linear accelerator. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-6016-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mishra S, Dixit PK, Selvam TP, Yavalkar SS, Deshpande DD. Monte Carlo Investigation of Photon Beam Characteristics and its Variation with Incident Electron Beam Parameters for Indigenous Medical Linear Accelerator. J Med Phys 2018; 43:1-8. [PMID: 29628627 PMCID: PMC5879818 DOI: 10.4103/jmp.jmp_125_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose A Monte Carlo model of a 6 MV medical linear accelerator (linac) unit built indigenously was developed using the BEAMnrc user code of the EGSnrc code system. The model was benchmarked against the measurements. Monte Carlo simulations were carried out for different incident electron beam parameters in the study. Materials and Methods Simulation of indigenously developed linac unit has been carried out using the Monte Carlo based BEAMnrc user-code of the EGSnrc code system. Using the model, percentage depth dose (PDD), and lateral dose profiles were studied using the DOSXYZnrc user code. To identify appropriate electron parameters, three different distributions of electron beam intensity were investigated. For each case, the kinetic energy of the incident electron was varied from 6 to 6.5 MeV (0.1 MeV increment). The calculated dose data were compared against the measurements using the PTW, Germany make RFA dosimetric system (water tank MP3-M and 0.125 cm3 ion chamber). Results The best fit of incident electron beam parameter was found for the combination of beam energy of 6.2 MeV and circular Gaussian distributed source in X and Y with FWHM of 1.0 mm. PDD and beam profiles (along both X and Y directions) were calculated for the field sizes from 5 cm × 5 cm to 25 cm × 25 cm. The dose difference between the calculated and measured PDD and profile values were under 1%, except for the penumbra region where the maximum deviation was found to be around 2%. Conclusions A Monte Carlo model of indigenous linac (6 MV) has been developed and benchmarked against the measured data.
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Affiliation(s)
- Subhalaxmi Mishra
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, India
| | - P K Dixit
- Radiological Safety Division, Atomic Energy Regulatory Board, Anushaktinagar, Mumbai, India.,Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, India
| | - T Palani Selvam
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, India
| | - Sanket S Yavalkar
- Technology Innovation Department, Society for Applied Microwave Electronics Engineering and Research, Mumbai, India
| | - D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
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Deshpande DD, Fleming TH, Gans ROB, Nawroth PP. Impaired Pro-opiomelanocortin (Pomc) – Mu Opioid Receptor (MOR) axis contributes to painful diabetic neuropathy in Streptozotocin induced mice. DIABETOL STOFFWECHS 2016. [DOI: 10.1055/s-0036-1580825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sahani G, Sharma SD, Sharma PKD, Deshpande DD, Negi PS, Sathianarayanan VK, Rath GK. Acceptance criteria for flattening filter-free photon beam from standard medical electron linear accelerator: AERB task group recommendations. J Med Phys 2014; 39:206-11. [PMID: 25525307 PMCID: PMC4258727 DOI: 10.4103/0971-6203.144482] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 09/25/2014] [Accepted: 09/29/2014] [Indexed: 11/13/2022] Open
Abstract
Medical electron linear accelerators with the capability of generating unflat photon (flattening filter-free, FFF) beams are also available commercially for clinical applications in radiotherapy. However, the beam characteristics evaluation criteria and parameters are not yet available for such photon beams. Atomic Energy Regulatory Board (AERB) of India constituted a Task Group comprising experts from regulatory agency, advisory body/research and technical institutions, and clinical radiotherapy centers in the country to evolve and recommend the acceptance criteria for the flattening filter-free (FFF) photon beams. The Task Group thoroughly reviewed the literature and inputs of the manufactures/suppliers of the FFF linac and recommended a set of dosimetry parameters for evaluating the characteristics of the unflat photon beam. The recommendations included the evaluation of quality index, degree of unflatness, difference in percentage surface dose between flat and unflat photon beams, percentage depth dose at 10 cm depth, off-axis-ratios and radiation beam penumbra. The recommended parameters were evaluated for FFF photon beams generated by three different models of the linac, and it was observed that recommended evaluation methods are simple and easy to be implemented with the existing dosimetry and quality assurance infrastructure of the linac facilities of the radiotherapy departments. Recommendations were also made for periodic quality control check of the unflat photon beams and constancy evaluation in the beam characteristics.
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Affiliation(s)
- G Sahani
- Radiological Safety Division, Atomic Energy Regulatory Board, Niyamak Bhavan, Mumbai, India
| | - S D Sharma
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CTCRS, Mumbai, India
| | - P K Dash Sharma
- Radiological Safety Division, Atomic Energy Regulatory Board, Niyamak Bhavan, Mumbai, India
| | - D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
| | - P S Negi
- Department of Medical Physics, Delhi State Cancer Institute, New Delhi, India
| | | | - G K Rath
- Dr. B. R. Ambedkar Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India
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Sharma PK, Sharma PK, Swamidas JV, Mahantshetty U, Deshpande DD, Manjhi J, Rai DV. Dose optimization in gynecological 3D image based interstitial brachytherapy using martinez universal perineal interstitial template (MUPIT) -an institutional experience. J Med Phys 2014; 39:197-202. [PMID: 25190999 PMCID: PMC4154188 DOI: 10.4103/0971-6203.139015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to evaluate the dose optimization in 3D image based gynecological interstitial brachytherapy using Martinez Universal Perineal Interstitial Template (MUPIT). Axial CT image data set of 20 patients of gynecological cancer who underwent external radiotherapy and high dose rate (HDR) interstitial brachytherapy using MUPIT was employed to delineate clinical target volume (CTV) and organs at risk (OARs). Geometrical and graphical optimization were done for optimum CTV coverage and sparing of OARs. Coverage Index (CI), dose homogeneity index (DHI), overdose index (OI), dose non-uniformity ratio (DNR), external volume index (EI), conformity index (COIN) and dose volume parameters recommended by GEC-ESTRO were evaluated. The mean CTV, bladder and rectum volume were 137 ± 47cc, 106 ± 41cc and 50 ± 25cc, respectively. Mean CI, DHI and DNR were 0.86 ± 0.03, 0.69 ± 0.11 and 0.31 ± 0.09, while the mean OI, EI, and COIN were 0.08 ± 0.03, 0.07 ± 0.05 and 0.79 ± 0.05, respectively. The estimated mean CTV D90 was 76 ± 11Gy and D100 was 63 ± 9Gy. The different dosimetric parameters of bladder D2cc, D1cc and D0.1cc were 76 ± 11Gy, 81 ± 14Gy, and 98 ± 21Gy and of rectum/recto-sigmoid were 80 ± 17Gy, 85 ± 13Gy, and 124 ± 37Gy, respectively. Dose optimization yields superior coverage with optimal values of indices. Emerging data on 3D image based brachytherapy with reporting and clinical correlation of DVH parameters outcome is enterprizing and provides definite assistance in improving the quality of brachytherapy implants. DVH parameter for urethra in gynecological implants needs to be defined further.
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Affiliation(s)
- Pramod Kumar Sharma
- Department of Medical Physics, International Oncology Center, Fortis Hospital, Noida, India ; Department of Radiation Oncology, Shobit University, Meerut, Uttar Pradesh, India
| | - Praveen Kumar Sharma
- Department of Radiation Oncology, International Oncology Center, Fortis Hospital, Noida, India
| | - Jamema V Swamidas
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, India
| | - Umesh Mahantshetty
- Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, India
| | - D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, India
| | - Jayanand Manjhi
- Department of Radiation Oncology, Shobit University, Meerut, Uttar Pradesh, India
| | - D V Rai
- Department of Radiation Oncology, Shobit University, Meerut, Uttar Pradesh, India
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Kinhikar RA, Pandey VP, Jose RK, Mahantshetty U, Dhote DS, Deshpande DD, Shrivastava SK. Investigation on the effect of sharp phantom edges on point dose measurement during patient-specific dosimetry with Rapid Arc. J Med Phys 2013; 38:139-42. [PMID: 24049321 PMCID: PMC3775038 DOI: 10.4103/0971-6203.116373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/18/2013] [Accepted: 07/05/2013] [Indexed: 11/21/2022] Open
Abstract
The objective of this work was to investigate and quantify the effect of sharp edges of the phantom on the point dose measurement during patient-specific dosimetry with Rapid Arc (RA). Ten patients with carcinoma of prostate were randomly selected for this dosimetric study. Rapid Arc plans were generated with 6 MV X-rays in the Eclipse (v 8.6.14) with single arc (clockwise). Dosimetry verification plans were generated for two phantoms (cylindrical and rectangular). The cylindrical phantom was solid water (diameter 34 cm) and the rectangular phantom was a water phantom (25 cm × 25 cm × 10 cm). These phantoms were pre-scanned in computed tomography (CT) machine with cylindrical ionization chamber (FC65) in place. The plans were delivered with Novalis Tx linear accelerator with 6 MV X-rays for both the phantoms separately. The measured dose was compared with the planned dose for both the phantoms. Mean percentage deviation between measured and planned doses was found to be 4.19 (SD 0.82) and 3.63 (SD 0.89) for cylindrical and rectangular phantoms, respectively. No significant dosimetric variation was found due to the geometry (sharp edges) of the phantom. The sharp edges of the phantom do not perturb the patient specific Rapid Arc dosimetry significantly.
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Affiliation(s)
- R A Kinhikar
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
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Affiliation(s)
- D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai - 400 012, India. E-mail:
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Jamema SV, Saju S, Shetty UM, Pallad S, Deshpande DD, Shrivastava SK. Dosimetric comparison of inverse optimization with geometric optimization in combination with graphical optimization for HDR prostate implants. J Med Phys 2011; 31:89-94. [PMID: 21206671 PMCID: PMC3004142 DOI: 10.4103/0971-6203.26694] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Accepted: 06/30/2006] [Indexed: 11/04/2022] Open
Abstract
The purpose of this study is to compare geometric optimization (GO) with anatomy based inverse optimization (ABIO). Five patients of carcinoma prostate treated with HDR interstitial brachytherapy had been studied. Post implant CT scans of 5 mm slice thickness were obtained; target volume and other critical structures rectum, bladder and urethra were drawn by the clinician. Plans were obtained with geometric optimization and anatomy based inversed optimization. Anatomy based inverse planning implemented currently in PLATO BPS version 14.2, is based on geometric and dose point optimization and designed to account for the critical structures. Graphical optimization (GrO) is used to fine-tune the distribution ie to reduce the dose to critical structures and to improve the target coverage in both geometric optimization and anatomy based inverse optimization plans. DVH of target, rectum, bladder and urethra were evaluated and compared, dose homogeneity index and conformity index were also evaluated for all the plans. The mean target coverage was 93.9±7%, 90.3±4%, 82±13%, 91.6±3 for different optimization techniques GO, GO_gr, ABIO and ABIO_gr respectively. The target coverage in ABIO is not clinically acceptable. Maximum dose, dose to 2% of the volume of urethra D(2%,U) was 137±12%, 123.2±2%, 111.5±9, 122.7±4 for GO, GO_gr, ABIO and ABIO_gr respectively. The mean conformity index values were 0.71, 0.76, 0.65, 0.82 for GO, GO_gr, ABIO, ABIO_gr respectively. ABIO_gr has a good conformity over all other optimization techniques. However the difference is not very significant between GO and GO_gr. The mean values of DHI are 0.81, 0.77, 0.65 and 0.75 for GO, GO_gr, ABIO and ABIO_gr respectively. Geometric optimization is highly homogenous compared to all other optimization techniques.To conclude, target coverage in ABIO is not clinically acceptable. However ABIO followed by graphical optimization is much superior in sparing of critical structures and conformity compared to geometrical optimization. Target coverage is marginally better in GO compared to ABIO_gr. Homogeneity is superior in GO compared to ABIO_gr. However ABIO_gr plans were clinically acceptable with respect to homogeneity. Further, dose escalation to the target is possible with ABIO, without exceeding the tolerance dose to urethra. Clinical correlation of genitourinary toxicity has to be studied.
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Affiliation(s)
- Swamidas V Jamema
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai - 400 012, India
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Jamema SV, Saju S, Mahantshetty U, Pallad S, Deshpande DD, Shrivastava SK, Dinshaw KA. Dosimetric evaluation of rectum and bladder using image-based CT planning and orthogonal radiographs with ICRU 38 recommendations in intracavitary brachytherapy. J Med Phys 2011; 33:3-8. [PMID: 20041045 PMCID: PMC2786096 DOI: 10.4103/0971-6203.39417] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 11/08/2007] [Indexed: 11/16/2022] Open
Abstract
The purpose is to compare CT-based dosimetry with International Commission on Radiation Units and Measurements (ICRU 38) bladder and rectum reference points in patients of carcinoma of uterine cervix treated with intracavitary brachytherapy (ICA). Twenty-two consecutive patients were evaluated. Orthogonal radiographs and CT images were acquired and transferred to PLATO planning system. Bladder and rectal reference points were identified according to ICRU 38 recommendations. Dosimetry was carried out based on Manchester system. Patient treatment was done using 192Iridium high dose rate (HDR) remote after-loading machine based on the conventional radiograph-based dosimetry. ICRU rectal and bladder point doses from the radiograph plans were compared with D2, dose received by 2 cm3 of the organ receiving maximum dose from CT plan. V2, volume of organ receiving dose more than the ICRU reference point, was evaluated. The mean (±standard deviation) volume of rectum and bladder was 60 (±28) cm3 and 138 (±41) cm3 respectively. The mean reference volume in radiograph and CT plan was 105 (±7) cm3 and 107 (±7) cm3 respectively. It was found that 6 (±4) cm3 of rectum and 16 (±10) cm3 of bladder received dose more than the prescription dose. V2 of rectum and bladder was 7 (±1.7) cm3 and 20.8 (±6) cm3 respectively. Mean D2 of rectum and bladder was found to be 1.11 (±0.2) and 1.56 (±0.6) times the mean ICRU reference points respectively. This dosimteric study suggests that comparison of orthogonal X-ray-based and CT-based HDR ICA planning is feasible. ICRU rectal point dose correlates well with maximum rectal dose, while ICRU bladder point underestimates the maximum bladder dose.
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Affiliation(s)
- Swamidas V Jamema
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
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Sharma PK, Jamema SV, Kaushik K, Budrukkar A, Jalali R, Deshpande DD, Tambe CM, Sarin R, Munshi A. Electron arc therapy for bilateral chest wall irradiation: treatment planning and dosimetric study. Clin Oncol (R Coll Radiol) 2010; 23:216-22. [PMID: 21185700 DOI: 10.1016/j.clon.2010.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 07/13/2010] [Accepted: 09/10/2010] [Indexed: 10/18/2022]
Abstract
AIMS The treatment of patients with synchronous bilateral breast cancer is a challenge. We present a report of dosimetric data of patients with bilateral chest walls as the target treated with electron arc therapy. MATERIALS AND METHODS Ten consecutive patients who had undergone electron arc therapy to the bilateral chest wall for breast cancer were analysed. After positioning and immobilisation, patients underwent computed tomography scans from the neck to the upper abdomen. Electron arc plans were generated using the PLATO RTS (V1.8.2 Nucletron) treatment planning system. Electron energy was chosen depending upon the depth and thickness of the planning target volume (PTV). For all patients, the arc angle ranged between 80 and 280° (start angle 80°, stop angle 280°). The homogeneity index, coverage index and doses to organs at risk were evaluated. The patient-specific output factor and thermoluminescence dosimetry (TLD) measurements were carried out for all patients. The total planned dose to the PTV was 50Gy/25 fractions/5 weeks. RESULTS The mean PTV (± standard deviation) was 568.9 (±116)cm(3). The mean PTV coverage was 89 (±5.8)% of the prescribed dose. For the right lung, the mean values of D(1) and D(10) were 46 (±7.6) and 30 (±9)Gy, respectively. For the left lung, the mean values of D(1) and D(10) were 45 (±7) and 27 (±8)Gy, respectively. For the heart, the mean values of D(1), D(5) and D(10) were 21 (±15), 13.5 (±12) and 9 (±9)Gy, respectively. The mean values of TLD at various pre-specified locations on the chest wall surface were 1.84, 1.82, 1.82, 1.89 and 1.78Gy, respectively CONCLUSION The electron arc technique for treating the bilateral chest wall is a feasible and pragmatic technique. This technique has the twin advantages of adequate coverage of the target volume and sparing of adjacent normal structures. However, compared with other techniques, it needs a firm quality assurance protocol for dosimetry and treatment delivery.
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Affiliation(s)
- P K Sharma
- Department of Medical Physics & Radiation Safety, International Oncology Centre, Fortis Hospital, Noida, India
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Budrukkar AN, Sarin R, Shrivastava SK, Deshpande DD, Dinshaw KA. Cosmesis, Late Sequelae and Local Control after Breast-Conserving Therapy: Influence of Type of Tumour Bed Boost and Adjuvant Chemotherapy. Clin Oncol (R Coll Radiol) 2007; 19:596-603. [PMID: 17706403 DOI: 10.1016/j.clon.2007.06.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2006] [Revised: 05/16/2007] [Accepted: 06/16/2007] [Indexed: 11/18/2022]
Abstract
AIMS To study the influence of various factors affecting cosmetic outcome and late sequelae in a large cohort of women treated with breast-conserving therapy. MATERIALS AND METHODS Between 1980 and 2000, 1022 pathological stage I/II breast cancer patients underwent breast-conserving therapy. On the basis of the type of tumour bed boost they received after whole breast radiotherapy, these women were assigned to three groups: (A) low dose rate (LDR) brachytherapy of 15-20 Gy (n=383); (B) high dose rate (HDR) brachytherapy of 10 Gy (optimised) in a single fraction (n=153); (C) electron beam 15 Gy/six fractions (n=460). Systemic adjuvant therapy was given to 757 women, of whom 570 received adjuvant chemotherapy. RESULTS Cosmesis at the last follow-up was good or excellent in 77% of women. Post-radiation worsening of cosmesis was observed in 11.5% of women and was similar in the three boost groups. Moderate to severe late breast sequelae were observed in 22% of women in group B, which was significantly higher than the 12% in group A (P=0.002) and 9% in group C (P=0.0001). The actuarial 5-year local control rate was 91% and was 90, 92 and 93% in groups A, B and C, respectively. Tumour size (P=0.049) and adjuvant chemotherapy (P=0.04) were the significant factors affecting cosmetic outcome on univariate analysis. On multivariate analysis, adjuvant chemotherapy was the only factor leading to worsening in the cosmetic outcome, with P=0.03 (hazard ratio 1.65 [95% confidence interval 1.05-2.59]). CONCLUSION The type of tumour bed boost did not have a significant effect on the worsening of cosmetic outcome. However, there were significantly more late breast sequelae in women treated with single fraction HDR implants. Chemotherapy had an adverse effect on the cosmetic outcome, but the late breast sequelae and local control rates were comparable.
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Affiliation(s)
- A N Budrukkar
- Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, India
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Kinhikar RA, Sharma S, Upreti R, Tambe CM, Deshpande DD, Shrivastava SK, Dinshaw KA. Commissioning of motorized wedge for the first equinox-80 telecobalt unit and implementation in the Eclipse 3D treatment planning system. Australas Phys Eng Sci Med 2007; 30:127-34. [PMID: 17682402 DOI: 10.1007/bf03178417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A new model of the telecobalt unit (TCU), Theratron Equinox-80, (MDS Nordion, Canada) equipped with a single 60 degree motorized wedge (MW), four universal wedges (UW) for 15 degrees, 30 degrees, 45 degrees and 60 degrees have been evaluated. MW was commissioned in Eclipse (Varian, Palo Alto, USA) 3D treatment planning system (TPS). The profiles and central axis depth doses (CADD) were measured with Wellhofer blue water phantom for MW and the measured data was commissioned in Eclipse. These profiles and CADD for MW were compared with UW in a homogeneous phantom generated in Eclipse for various field sizes. The dose was also calculated in the same phantom at 10 cm depth. For the particular MW angle and the respective open and MW beam weights, the dose was measured for a field size of 10 cm x 10 cm in a MEDTEC water phantom at 10 cm depth with a 0.13 cc thimble ion chamber (Scanditronix Wellhofer, Uppsala, Sweden) and a NE electrometer (Nuclear Enterprises, UK). Measured dose with ion chamber was compared with the TPS calculated dose. MW angle verification was also done on the Equinox for four angles (15 degrees, 30 degrees, 45 degrees and 60 degrees). The variation in measured and calculated dose at 10 cm depth was within 2%. The measured and the calculated wedge angles were in good agreement within 2 degrees. The motorized wedges were successfully commissioned in Eclipse for four wedge angles.
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Affiliation(s)
- R A Kinhikar
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, India.
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Kinhikar RA, Upreti R, Sharma S, Tambe CM, Deshpande DD. Intensity modulated radiotherapy dosimetry with ion chambers, TLD, MOSFET and EDR2 film. Australas Phys Eng Sci Med 2007; 30:25-32. [PMID: 17508598 DOI: 10.1007/bf03178406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Purpose of this study was to report in a together our experience of using ion chambers, TLD, MOSFET and EDR2 film for dosimetric verification of IMRT plans delivered with dynamic multileaf collimator (DMLC). Two ion chambers (0.6 and 0.13 CC) were used. All measurements were performed with a 6MV photon beam on a Varian Clinac 6EX LINAC equipped with a Millennium MLC. All measurements were additionally carried out with (LiF:Mg,TI) TLD chips. Five MOSFET detectors were also irradiated. EDR2 films were used to measure coronal planar dose for 10 patients. Measurements were carried out simultaneously for cumulative fields at central axis and at off-axis at isocenter plane (+/- 1, and +/- 2 cm). The mean percentage variation between measured cumulative central axis dose with 0.6 cc ion chamber and calculated dose with TPS was -1.4% (SD 3.2). The mean percentage variation between measured cumulative absolute central axis dose with 0.13 cc ion chamber and calculated dose with TPS was -0.6% (SD 1.9). The mean percentage variation between measured central axis dose with TLD and calculated dose with TPS was -1.8% (SD 2.9). A variation of less than 5% was found between measured off-axis doses with TLD and calculated dose with TPS. For all the cases, MOSFET agreed within +/- 5%. A good agreement was found between measured and calculated isodoses. Both ion chambers (0.6 CC and 0.13 CC) were found in good agreement with calculated dose with TPS.
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Affiliation(s)
- R A Kinhikar
- Department of Medical Physics, Tata Memorial Hospital, Dr. Ernest Borges Marg, Parel, Mumbai, India.
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Upreti RR, Dayananda S, Bhalawat RL, Bedre GN, Deshpande DD. Evaluation of radiograph-based interstitial implant dosimetry on computed tomography images using dose volume indices for head and neck cancer. J Med Phys 2007; 32:60-4. [PMID: 21157536 PMCID: PMC3000532 DOI: 10.4103/0971-6203.33242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Accepted: 03/20/2007] [Indexed: 11/28/2022] Open
Abstract
Conventional radiograph-based implant dosimetry fails to correlate the spatial dose distribution on patient anatomy with lack in dosimetry quality. Though these limitations are overcome in computed tomography (CT)-based dosimetry, it requires an algorithm which can reconstruct catheters on the multi-planner CT images. In the absence of such algorithm, we proposed a technique in which the implanted geometry and dose distribution generated from orthogonal radiograph were mapped onto the CT data using coordinate transformation method. Radiograph-based implant dosimetry was generated for five head and neck cancer patients on Plato Sunrise treatment planning system. Dosimetry was geometrically optimized on volume, and dose was prescribed according to the natural prescription dose. The final dose distribution was retrospectively mapped onto the CT data set of the same patients using coordinate transformation method, which was verified in a phantom prior to patient study. Dosimetric outcomes were evaluated qualitatively by visualizing isodose distribution on CT images and quantitatively using the dose volume indices, which includes coverage index (CI), external volume index (EI), relative dose homogeneity index (HI), overdose volume index (OI) and conformal index (COIN). The accuracy of coordinate transformation was within ±1 mm in phantom and ±2 mm in patients. Qualitative evaluation of dosimetry on the CT images shows reasonably good coverage of target at the expense of excessive normal tissue irradiation. The mean (SD) values of CI, EI and HI were estimated to be 0.81 (0.039), 0.55 (0.174) and 0.65 (0.074) respectively. The maximum OI estimated was 0.06 (mean 0.04, SD = 0.015). Finally, the COIN computed for each patient ranged from 0.4 to 0.61 (mean 0.52, SD = 0.078). The proposed technique is feasible and accurate to implement even for the most complicated implant geometry. It allows the physicist and physician to evaluate the plan both qualitatively and quantitatively. Dose volume indices derived from CT data set are useful for evaluating the implant and comparing different brachytherapy plans. COIN index is an important tool to assess the target coverage and sparing of normal tissues in brachytherapy.
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Affiliation(s)
- Ritu Raj Upreti
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
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Pandya MV, Deshpande DD, Hundiwale DG, Kapadi UR. Reinforcement in Polybutadiene (PB) with Inorganic Fillers System I—Barium Chloride (Hydrate and Anhydrous) and Barium Fluoride. INT J POLYM MATER PO 2006. [DOI: 10.1080/00914038408080269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sharma DS, Deshpande SS, Phurailatpam RD, Deshpande DD, Shrivastava SK, Dinshaw KA. Peripheral dose from uniform dynamic multileaf collimation fields: implications for sliding window intensity-modulated radiotherapy. Br J Radiol 2006; 79:331-5. [PMID: 16585727 DOI: 10.1259/bjr/16208090] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The increase in the number of monitor units in sliding window intensity-modulated radiotherapy, compared with conventional techniques for the same target dose, may lead to an increase in peripheral dose (PD). PD from a linear accelerator was measured for 6 MV X-ray using 0.6 cm3 ionization chamber inserted at 5 cm depth into a 35 cm x 35 cm x 105 cm plastic water phantom. Measurements were made for field sizes of 6 cm x 6 cm, 10 cm x 10 cm and 14 cm x 14 cm, shaped in both static and dynamic multileaf collimation (DMLC) mode, employing strip fields of fixed width 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm, respectively. The effect of collimator rotation and depth of measurement on peripheral dose was investigated for 10 cm x 10 cm field. Dynamic fields require 2 to 14 times the number of monitor units than does a static open field for the same dose at the isocentre, depending on strip field width and field size. Peripheral dose resulting from dynamic fields manifests two distinct regions showing a crest and trough within 30 cm from the field edge and a steady exponential fall beyond 30 cm. All dynamic fields were found to deliver a higher PD compared with the corresponding static open fields, being highest for smallest strip field width and largest field size; also, the percentage increase observed was highest at the largest out-of-field distance. For 6 cm x 6 cm field, dynamic fields with 0.5 cm and 2 cm strip field width deliver PDs 8 and 2 times higher than that of the static open field. The corresponding factors for 14 cm x 14 cm field were 15 and 6, respectively. The factors by which PD for DMLC fields increase, relative to jaws-shaped static fields for out-of-field distance beyond 30 cm, are almost the same as the corresponding increases in the number of monitor units. Reductions of 20% and 40% in PD were observed when the measurements were done at a depth of 10 cm and 15 cm, respectively. When the multileaf collimator executes in-plane (collimator 90 degrees) motion, peripheral dose decreases by as much as a factor of 3 compared with cross-plane data. The knowledge of PD from DMLC field is necessary to estimate the increase in whole-body dose and the likelihood of radiation induced secondary malignancy.
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Affiliation(s)
- D S Sharma
- Department of Medical Physics, Tata Memorial Hospital, Dr. Ernest Borges Marg, Parel, Mumbai, 400 012, India
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Sharma DS, Sharma SD, Sanu KK, Saju S, Deshpande DD, Kannan S. Performance evaluation of a dedicated computed tomography scanner used for virtual simulation using in-house fabricated CT phantoms. J Med Phys 2006; 31:28-35. [PMID: 21206637 PMCID: PMC3003891 DOI: 10.4103/0971-6203.25667] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Accepted: 03/24/2006] [Indexed: 11/04/2022] Open
Abstract
Comprehensive tests on single slice CT scanner was carried out using in-house fabricated phantoms/test tools following AAPM recommended methods to independently validate the auto-performance test (APT) results. Test results of all the electromechanical parameters were found within the specified limits. Radiation and sensitivity profile widths were within ± 0.05 cm of the set slice thickness. Effective energy corresponding to nominal kVp of 80, 110 and 130 were 49.99, 55.08 and 59.48 keV, respectively. Percentage noise obtained by APT was 1.32% while the independently measured value was 0.38%. Observed contrast resolutions by independent method at 0.78% and 12% contrast difference were 4 mm and 1.25 mm (= 4 lp/cm) respectively. However, high contrast resolution (limiting spatial resolution) by APT at 50, 10 and 2% MTF levels were 9, 12.5 and 14.1 lp/cm respectively. Difference in calculated and measured CT numbers of water, air, teflon, acrylic, polystyrene and polypropylene were in the range of 0 to 24 HU, while this difference was 46 and 94 HU in case of nylon and bakelite respectively. The contrast scale determined using CT linearity phantom was 1.998×10−4 cm−1/CT number. CT dose index (CTDI) and weighted CTDI (CTDIw) measured at different kVp for standard head and body phantoms were smaller than manufacturer-specified and system-calculated values and were found within the manufacturer-specified limit of ± 20%. Measured CTDIs on surface (head: 3.6 cGy and body: 2.6 cGy) and at the center (3.3 cGy, head; and 1.2 cGy, body) were comparable to reported values of other similar CT scanners and were also within the industry-quoted CTDI range. Comprehensive QA and independent validation of APT results are necessary to obtain baseline data for CT virtual simulation.
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Affiliation(s)
- D S Sharma
- Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, India
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Pandya MV, Deshpande DD, Hundiwale DG. Effect of diisocyanate structure on viscoelastic, thermal, mechanical and electrical properties of cast polyurethanes. J Appl Polym Sci 2003. [DOI: 10.1002/app.1986.070320518] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Deshpande DD, Patterson D, Schreiber HP, Su CS. Thermodynamic Interactions in Polymer Systems by Gas-Liquid Chromatography. IV. Interactions between Components in a Mixed Stationary Phase. Macromolecules 2002. [DOI: 10.1021/ma60040a023] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Deshpande DD, Tyagi OS. Gas Chromatographic Behavior of Poly(vinyl acetate) at Temperatures Encompassing T g : Determination of T g and η. Macromolecules 2002. [DOI: 10.1021/ma60064a026] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Budrukkar AN, Shrivastava SK, Jalali R, Agarwal JP, Deshpande DD, Nehru RM, Dinshaw KA. Transperineal low-dose rate iridium-192 interstitial brachytherapy in cervical carcinoma stage IIB. Strahlenther Onkol 2001; 177:517-24. [PMID: 11680016 DOI: 10.1007/pl00002362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To assess local control, survival and complications in patients with cervical carcinoma Stage IIB treated radically with transperineal Iridium-192 low-dose rate interstitial brachytherapy following external beam radiotherapy. PATIENTS AND METHODS 65 women (age 25-70 years, mean 47 years) with cervical carcinoma Stage IIB were initially treated with external beam radiotherapy on a telecobalt or 6 MV linear accelerator to a dose of 50 Gy delivered in 5-6 weeks. After 2-3 weeks of completing external radiation, patients received interstitial brachytherapy with Iridium-192 (activity 0.5-1 mCi/cm) using a Syed-Neblett perineal template. The median dose delivered to the implant volume was 24 Gy (range 20-32 Gy) delivered at an average dose rate of 0.70 Gy/h (range 0.40-1.20 Gy/h). A point defined at 1.5 cm lateral to the central uterine tandem at the level of os was taken as a representative for assessing the dose to the cervix. Mean doses delivered by interstitial brachytherapy to point A, cervix, point B and rectum were 38 Gy, 34 Gy, 16 Gy and 16 Gy, respectively. RESULTS At a median follow-up of 53 months, the actuarial disease free survival and overall survival for 65 patients at both 5 and 10 years was 64% and 44%, respectively. Response to radiotherapy was a strong predictor of local control with 82% of patients continuing to have pelvic control after initial complete response. Overall, nine (14%) patients had persistent disease, ten (15%) developed a central recurrence after initial control and three patients developed distant metastasis on follow-up. No patient had any immediate treatment-related complication. Late toxicity included grade I-II rectal reactions in five patients and grade IV bladder complication (vesico-vaginal fistula) in two patients. 5 years after treatment, one patient developed intestinal obstruction, which was relieved after conservative management. Two patients developed vaginal stenosis. The 5- and 10-year disease free survival was 48% in patients aged less than 45 years as compared to 80% in patients of more than 45 years (p = 0.009). Dose to the cervical point was a prognostic indicator with 5- and 10-year disease free survival of 47% in patients who received < 35 Gy in comparison to 80% in patients who had > 35 Gy (p = 0.03). There was no difference in local control and survival in patients with minimal and moderate parametrial involvement. Bulky disease (> 4 cm) at presentation and a longer gap between external radiation and brachytherapy showed a trend towards inferior local control. CONCLUSIONS Interstitial brachytherapy after external beam irradiation in patients with cervical carcinoma Stage IIB results in acceptable local control, survival and complication rates. Increased dose to the cervical disease results in improved local control and survival and should therefore be considered while optimizing brachytherapy treatment plans. Comparison of the results with those of standard intracavitary therapy remains to be proven in a randomized trial.
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Affiliation(s)
- A N Budrukkar
- Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, India
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Pingley S, Shrivastava SK, Sarin R, Agarwal JP, Laskar S, Deshpande DD, Dinshaw KA. Primary carcinoma of the vagina: Tata Memorial Hospital experience. Int J Radiat Oncol Biol Phys 2000; 46:101-8. [PMID: 10656380 DOI: 10.1016/s0360-3016(99)00360-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Carcinoma of the vagina is a rare gynecological malignancy comprising approximately 2% of all the gynecological malignancies. We have analyzed the treatment outcome of the patients treated at the Tata Memorial Hospital from January 1984 to December 1993. METHODS AND MATERIALS In this 10-year period, 134 patients of primary vaginal cancers were registered at our hospital. Of these, 75 patients received complete treatment and are analyzed. RESULTS Disease-free survival (DFS) for the whole group is 50%, and overall survival (OAS) is 60%. Most locoregional recurrences and distant failures are noted in the 2 years following treatment. DFS at 5 years is as follows: Stage I (5 patients), Stage IIA (37 patients), Stage IIB (15 patients), Stage III (14 patients), and Stage IV (4 patients); are 40%, 55%, 60%, 50%, and 25%, respectively. The DFS for patients with complete response (42 patients) to external radiation at 5 years is 68%, with partial response (25 patients) is 35%, and with poor or no response (6 patients) is 18% (p = 0.0000). We observed that brachytherapy was an important part of the treatment, and patients who received brachytherapy (59 patients), either with a vaginal intracavitary applicator (30 patients) or interstitial implant (29 patients) had a DFS of 53% and 56%, respectively, while 15 patients who received external radiation alone had a DFS of 30%. Patients receiving brachytherapy within 4 weeks of external radiation had a DFS of 60% as compared to 30% when the interval was more than 4 weeks. CONCLUSION The factors indicating prognosis are: site and extent of involvement, presence of lymph nodes at presentation, technique of brachytherapy, and interval between external radiation and brachytherapy.
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Affiliation(s)
- S Pingley
- Department of Radiation Oncology, Tata Memorial Hospital, Parel, India
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Deshpande DD, Shrivastav SK, Pradhan AS, Viswanathan PS, Dinshaw KA. Dosimetry of intracavitary applications in carcinoma of the cervix: rectal dose analysis. Radiother Oncol 1997; 42:163-6. [PMID: 9106925 DOI: 10.1016/s0167-8140(96)01841-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The International Commission on Radiation Units and Measurements (ICRU), in its Report-38, has given certain recommendations regarding the specifications of bladder and rectal reference points in the intracavitary treatment of carcinoma of the cervix. Conforming to this report, 182 intracavitary applications performed in stage I and II cervix cases were analyzed. In 113 applications, the maximum rectal dose was found to be in a point on the anteroposterior line drawn through the centre of colpostat sources. However, for our type of applications, the point on the anteroposterior line drawn through the lower end of the uterine tube seldom gets maximum dose. In addition, it was observed that there are other dose points than the ICRU reference point receiving doses close to maximum dose. It was concluded that doses to multiple rectal reference points should be recorded, in addition to the ICRU-defined rectal reference point.
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Affiliation(s)
- D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Parel, Bombay, India
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Avadhani JS, Deshpande DD, Pradhan AS, Viswanathan PS, Shrivastava SK, Dinshaw KA. Design and comparison of wedge shaped midline block with rectangular block used in early stage cervical cancers. Strahlenther Onkol 1996; 172:676-80. [PMID: 8972752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Design of an universal wedge shaped midline block for early stage cervical cancers to get uniform dose distribution around the target volume. MATERIAL AND METHODS The method of fabrication of wedge shaped midline block is discussed for treatment of early stage cervical cancers based on the configuration of 137Cs pellets used in intracavitary applications and along with external photon beams obtained by using 60Co teletherapy machine and 6 and 10 MV linear accelerators. RESULTS The dosimetric measurements are carried out to confirm the adequacy of thickness and shape of the block using radiation field analyzer for all the 3 energies. DISCUSSION The dose distribution comparison has been made with wedge shaped midline block and conventional rectangular shields to show its superiority in getting homogeneous dose distribution around target volume. The shift in 184 intracavitary applications is analyzed in actual clinical applications with respect to central axis of external beams and its comparison is made with both types of blocks. With the shift of 1 cm towards lateral from midline an overdose can occur upto 12 Gy at certain points with rectangular block compared to wedge shaped midline block. CONCLUSION Since the preparation of individual wedge shaped midline block for every application will be a difficult process for busy centers, the single wedge shaped midline block for each energy is more convenient to handle for busy centers instead of individualized compensating blocks for every intracavitary application.
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Affiliation(s)
- J S Avadhani
- Department of Medical Physics, Tata Memorial Hospital, Mumbai, India
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Deshpande DD, Shrivastava SK, Pradhan AS, Viswanathan PS, Dinshaw KA. Geometrical considerations in dose volume analysis in intracavitary treatment. Strahlenther Onkol 1996; 172:326-9. [PMID: 8677505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE The present work was aimed at to study the relationship between the volume enclosed by reference isodose surface and various geometrical parameters of the intracavitary applicator in treatment of carcinoma of cervix. MATERIAL AND METHODS Pearshape volume of the reference isodose derived from the Total Reference Air Kerma (TRAK) and the product of its dimensions, height H, width W and thickness T which is dependent on the applicator geometry, were estimated for 100 intracavitary applications treated by Selectron LDR machine. Orthogonal radiographs taken for each patient were used for measurement of actual geometric dimensions of the applicator and carrying out the dosimetry on TP-11 treatment planning system. The dimensions H, W and T of reference isodose surface (60 Gy) were also noted. RESULTS Ratio of the product HWT and the pearshape volume was found mainly to be a function of colpostat separation and not of other geometrical parameters like maximum vertical and anterio-posterior dimension of the applicator. The ratio remained almost constant for a particular combination of uterine tandem and colpostat. Variation in the ratios were attributed to the non-standard geometry. CONCLUSION The ratio of the volume of reference isodose surface to the product of its dimensions in the applicator depends upon the colpostat separation.
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Affiliation(s)
- D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Bombay, India
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Kapadi UR, Hundiwale DG, Pandya MV, Deshpande DD. Reinforcement in Polybutadiene by Metal Oxides. INT J POLYM MATER PO 1994. [DOI: 10.1080/00914039408029330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Deshpande DD, Shrivastava SK, Nehru RM, Viswanathan PS, Dinshaw KA. Treatment volume from total reference air kerma (TRAK) in intracavitory applications and its comparison with ICRU reference volume. Int J Radiat Oncol Biol Phys 1994; 28:499-504. [PMID: 8276667 DOI: 10.1016/0360-3016(94)90077-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE A systematic dosimetry study conforming to International Commission on Radiation Units and Measurements Report Number 38, was carried out for, cancer of Cervix Stage I and II cases at Tata Memorial Hospital. METHODS AND MATERIALS The reference Volume dimension were noted for each applicator. Also 3-D dosimetry was performed for selected cases, and actual geometric volume enclosed by various isodose surfaces were obtained. A relation was derived, which gave the volume enclosed by any isodose surface as a function of total reference air kerma of the sources in the applicator. The volume enclosed by reference isodose surface was compared with the product of its dimensions height, width, and thickness. RESULTS The volume enclosed by any isodose surface of an intracavitary application can be easily derived from total reference air kerma of the sources within the applicator. CONCLUSION Ratio of the volume enclosed by reference isodose surface with the product of its dimensions (HWT) could be a predictive parameter for clinical outcome, besides the reference volume specified by the report.
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Affiliation(s)
- D D Deshpande
- Department of Medical Physics, Tata Memorial Hospital, Parel, Bombay, India
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Joshi CP, Avadhani JS, Deshpande DD, Pendse AM, Viswanathan PS, Dinshaw KA. CT assisted computation of collimator angle and importance of off-axis planning of inclined lesions. Strahlenther Onkol 1993; 169:495-9. [PMID: 8356509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In the radiation treatment of inclined lesions the longitudinal axis of beam should be always parallel to the longitudinal axis of lesion in the treatment plane. Hence the choice of correct collimator angle is of prime importance in the oblique field off-axis treatment planning of inclined lesions. In this paper a graphical method is discussed to determine the collimator angles from the CT scans taken at different off-axis planes. A phantom was constructed which can simulate conditions like inclined lesion in the patient and CT scans were taken at different levels. The collimator angles estimated from CT scans are found to match with the collimator angles obtained from simulator within +/- 1 degree for various gantry angles. The method is applied to plan a case of cancer of the oesophagus (upper third), which is a typical example of inclined lesion.
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Affiliation(s)
- C P Joshi
- Department of Medical Physics, Tata Memorial Hospital, Parel, Bombay, India
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Pandya MV, Deshpande DD, Hundiwale DG, Kapadi UR. Dynamic Mechanical Properties of Filled Polybutadiene. INT J POLYM MATER PO 1992. [DOI: 10.1080/00914039208034809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Fourteen patients with malignant airway obstruction were treated with a placement of a flexible nylon catheter for low dose rate manual afterloading Iridium 192 endobronchial brachytherapy using a flexible fibreoptic bronchoscope. Eight patients had obstructive pneumonitis at initial presentation, while 6 cases were recurrences after previous external irradiation. Six evaluable patients of the former group had complete or partial reinflation of lung and were followed by external radiotherapy. Of the latter group, 3 were evaluable and had moderate to good palliation of their symptoms. No complication was observed. The technique is simple and safe with good patient compliance. Further evaluation is indicated to assess its role in the locoregional management of lung cancer.
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Affiliation(s)
- S S Susnerwala
- Department of Radiation Oncology, Tata Memorial Hospital, Bombay, India
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Murthy CN, Patni MJ, Deshpande DD, Kudchadker AP, Mehta MH, Ankleshwaria BV. Interpenetrating polymer networks of castor oil polyester and poly(methyl methacrylate). J Appl Polym Sci 1991. [DOI: 10.1002/app.1991.070430517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Raghavan D, Shaligram AM, Deshpande DD. The influence of charge density and steric factor of aminated chloromethyl polystyrene homologs in bilirubin adsorption. J Appl Polym Sci 1991. [DOI: 10.1002/app.1991.070420913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ramakrishna MS, Deshpande DD, Babu GN. Radiation-induced copolymerization of hydrophilic monomers: Synthesis and thermal properties. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/pola.1988.080260209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Tyagi OS, Deshpande DD. Inverse gas chromatography of poly(n-butyl methacrylate): Effect of flow rate on specific retention volume and detection of glass transition temperature. J Appl Polym Sci 1987. [DOI: 10.1002/app.1987.070340704] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Deshpande DD, Kandaswamy NR, Tiwari VK. Dielectric and dynamic mechanical behavior of poly(vinyl acetate) containing small concentrations of cholesteryl additives. J Appl Polym Sci 1985. [DOI: 10.1002/app.1985.070300714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Deshpande DD, Tiwari VK. Dielectric and Dynamic Mechanical Behaviour of Poly(vinylchloride) Containing Small Amounts of Cholesterol, Cholesteryl Chloride, and Cholesteryl Benzoate. Polym J 1983. [DOI: 10.1295/polymj.15.377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Patil AO, Deshpande DD, Talwar SS, Biswas AB. Photocrosslinking and thermal behavior of the polyesters containing conjugated diacetylenes. ACTA ACUST UNITED AC 1981. [DOI: 10.1002/pol.1981.170190512] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Deshpande DD, Oswal SL. Vapour-liquid equilibrium and excess free energies for benzene + dioxan and carbon tetrachloride + dioxan systems. ACTA ACUST UNITED AC 1972. [DOI: 10.1039/f19726801059] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
This paper presents the
experimental results on the velocity of sound, densities, and heat capacities
of eight organic liquids at 25�, 35�, and 45�C. Using Eyring's equation, the
free volumes have been calculated from the sound velocity data. For pure liquids,
a quantity Cv* = (Cv)L- (Cv)g-
Cstr called the residual heat capacity is found to be linearly
dependent on free volume. Analysis of the data for 34 liquids shows that a plot
of residual heat capacity against the free volume gives a series of straight lines
differing in slopes for different groups of liquids such as hydrocarbons,
halogen-substituted hydrocarbons, alcohols, etc. This behaviour is ascribed as
being due to different degrees of rotational freedom of molecules in these liquids.
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Deshpande DD, Pandya MV. Thermodynamics of binary solutions. Part 2.—Vapour pressures and excess free energies of aniline solutions. ACTA ACUST UNITED AC 1967. [DOI: 10.1039/tf9676302149] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Deshpande DD, Pandya MV. Thermodynamics of binary solutions. Part 1.—Heats of mixing of aniline in benzene, carbontetrachloride and chlorobenzene. ACTA ACUST UNITED AC 1965. [DOI: 10.1039/tf9656101858] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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