Mary Joan M - Academia.edu (original) (raw)

Papers by Mary Joan M

Research paper thumbnail of Estimation of monitor unit through analytical method for dynamic IMRT using control points as an effective parameter

The control points (CP) play a significant role in the delivery of segmented based Intensity-Modu... more The control points (CP) play a significant role in the delivery of segmented based Intensity-Modulated Radiation Therapy (IMRT) delivery, particularly in dynamic mode. The number of segments is determined by control points and these segments will transfer from one to the other either during beam ON called dynamic delivery or during beam OFF called static delivery or step and shoot. This study was aimed at indirect estimation of the total monitor units (MU) to be delivered per field by exploiting the control points and also to find the MUs at any nth segment. This study was performed in the Eclipse treatment planning software version 13.8.0. The details of control points, metre set weight per segment, leaf positions for each segment, field size, etc. were taken into consideration. TPS calculated MU value and analytically estimated MU value were compared and the percentage of difference was estimated. The overall mean percentage of deviation was 1·03% between the TPS calculated method...

Research paper thumbnail of Out-Of-Field Dose Measurement and Second Cancer-Risk Estimation Following External Beam Radiotherapy and Brachytherapy for Cervical Cancer Treatment: A Phantom Study

Introduction: The present study aimed to measure the scatter and leakage dose received by out-of-... more Introduction: The present study aimed to measure the scatter and leakage dose received by out-of-field organs while delivering Radiotherapy (RT) treatment of cervical cancer. Moreover, this study estimated the risk of second cancer (SC). The doses to out-of-field organs were measured using a lithium fluoride (TLD 100) dosimeter while delivering External Beam Radiotherapy (EBRT) by 6 MV photon beam with Brachytherapy Boost (BB) treatment in the humanoid phantom. Material and Methods: The excess absolute risk of SC for the stomach, colon, liver, lung, breast, and kidney, as well as excess relative risk for the thyroid, were estimated based on Biological Effects of Ionizing Radiation VII report. Results: The out-of-field organ doses varied with respect to distance between organs. The colon (3DCRT-282.13 cGy and IMRT-381.24 cGy in 25 fractions) and kidney (70.65 cGy in 3 fractions) received the highest doses with EBRT and BB, respectively. For most of the aforementioned organs, the calc...

Research paper thumbnail of An Evaluation of the Effects of Brachytherapy Applicator Attenuation in the High Dose Rate Treatment for Carcinoma Uterine Cervix

RUHS Journal of Health Science, Dec 31, 2018

Research paper thumbnail of Effect of Radiotherapy on Antioxidant Vitamin E in Patients with Carcinoma Uterine Cervix- a Pilot Study

Journal of Oncology and Cancer Research, Mar 23, 2017

Research paper thumbnail of On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator

Journal of Medical Physics, 2016

Transmission of radiation fluence through patient's body has a correlation to the planned target ... more Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (S t) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. S t s were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (D iso,TPS), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (D iso,Transit) from the measured S t s. A locally fabricated pelvic phantom validated the estimations of D iso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The D iso,Transit agreement with D iso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is −1.37% ±2.03% (n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

Research paper thumbnail of Estimation of radiation-induced second cancer risk associated with the institutional field matching craniospinal irradiation technique: A comparative treatment planning study

Reports of Practical Oncology & Radiotherapy

Aim: To estimate and compare the lifetime attributable risk (LAR) of radiation-induced second can... more Aim: To estimate and compare the lifetime attributable risk (LAR) of radiation-induced second cancer (SC) in pediatric medulloblastoma patients planned with institutional 3D conformal field matching method, gap junction method and Intensity Modulated Radiotherapy (IMRT). Background: The epidemiological studies on childhood cancer survivors reported that longterm cancer survivors who received radiotherapy are at a significantly increased risk for the development of SC. Hence, the increased concern to predict the SC risk for long-term survivors. Materials and methods: In addition to institutional field matching planning method, IMRT and gap junction methods were created for ten pediatric medulloblastoma patients. The risk estimates were made based on the site-specific cancer risk coefficient provided by the BEIR VII committee according to the organ equivalent dose for various critical organs. Also, plans were compared for target volume dose distribution and dose received by critical organs. Results: When compared to the gap junction method, the IMRT and institutional field matching method were superior in normal tissue sparing and dose conformity. However, highly significant volume of low dose associated with IMRT was the main concern for the SC risk. The accumulated LAR for all the critical organs with 3D conformal gap junction and IMRT method was 23-25% while for the 3D conformal field matching method it was 21%. Conclusion: The LAR associated with the institutional field matching technique was substantially lower. As this method is highly robust and easy to set up, it can be a better choice of a craniospinal irradiation technique where 3DCRT is the only choice of treatment.

Research paper thumbnail of Estimation of monitor unit through analytical method for dynamic IMRT using control points as an effective parameter

The control points (CP) play a significant role in the delivery of segmented based Intensity-Modu... more The control points (CP) play a significant role in the delivery of segmented based Intensity-Modulated Radiation Therapy (IMRT) delivery, particularly in dynamic mode. The number of segments is determined by control points and these segments will transfer from one to the other either during beam ON called dynamic delivery or during beam OFF called static delivery or step and shoot. This study was aimed at indirect estimation of the total monitor units (MU) to be delivered per field by exploiting the control points and also to find the MUs at any nth segment. This study was performed in the Eclipse treatment planning software version 13.8.0. The details of control points, metre set weight per segment, leaf positions for each segment, field size, etc. were taken into consideration. TPS calculated MU value and analytically estimated MU value were compared and the percentage of difference was estimated. The overall mean percentage of deviation was 1·03% between the TPS calculated method...

Research paper thumbnail of Out-Of-Field Dose Measurement and Second Cancer-Risk Estimation Following External Beam Radiotherapy and Brachytherapy for Cervical Cancer Treatment: A Phantom Study

Introduction: The present study aimed to measure the scatter and leakage dose received by out-of-... more Introduction: The present study aimed to measure the scatter and leakage dose received by out-of-field organs while delivering Radiotherapy (RT) treatment of cervical cancer. Moreover, this study estimated the risk of second cancer (SC). The doses to out-of-field organs were measured using a lithium fluoride (TLD 100) dosimeter while delivering External Beam Radiotherapy (EBRT) by 6 MV photon beam with Brachytherapy Boost (BB) treatment in the humanoid phantom. Material and Methods: The excess absolute risk of SC for the stomach, colon, liver, lung, breast, and kidney, as well as excess relative risk for the thyroid, were estimated based on Biological Effects of Ionizing Radiation VII report. Results: The out-of-field organ doses varied with respect to distance between organs. The colon (3DCRT-282.13 cGy and IMRT-381.24 cGy in 25 fractions) and kidney (70.65 cGy in 3 fractions) received the highest doses with EBRT and BB, respectively. For most of the aforementioned organs, the calc...

Research paper thumbnail of An Evaluation of the Effects of Brachytherapy Applicator Attenuation in the High Dose Rate Treatment for Carcinoma Uterine Cervix

RUHS Journal of Health Science, Dec 31, 2018

Research paper thumbnail of Effect of Radiotherapy on Antioxidant Vitamin E in Patients with Carcinoma Uterine Cervix- a Pilot Study

Journal of Oncology and Cancer Research, Mar 23, 2017

Research paper thumbnail of On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator

Journal of Medical Physics, 2016

Transmission of radiation fluence through patient's body has a correlation to the planned target ... more Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (S t) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. S t s were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (D iso,TPS), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (D iso,Transit) from the measured S t s. A locally fabricated pelvic phantom validated the estimations of D iso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The D iso,Transit agreement with D iso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is −1.37% ±2.03% (n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

Research paper thumbnail of Estimation of radiation-induced second cancer risk associated with the institutional field matching craniospinal irradiation technique: A comparative treatment planning study

Reports of Practical Oncology & Radiotherapy

Aim: To estimate and compare the lifetime attributable risk (LAR) of radiation-induced second can... more Aim: To estimate and compare the lifetime attributable risk (LAR) of radiation-induced second cancer (SC) in pediatric medulloblastoma patients planned with institutional 3D conformal field matching method, gap junction method and Intensity Modulated Radiotherapy (IMRT). Background: The epidemiological studies on childhood cancer survivors reported that longterm cancer survivors who received radiotherapy are at a significantly increased risk for the development of SC. Hence, the increased concern to predict the SC risk for long-term survivors. Materials and methods: In addition to institutional field matching planning method, IMRT and gap junction methods were created for ten pediatric medulloblastoma patients. The risk estimates were made based on the site-specific cancer risk coefficient provided by the BEIR VII committee according to the organ equivalent dose for various critical organs. Also, plans were compared for target volume dose distribution and dose received by critical organs. Results: When compared to the gap junction method, the IMRT and institutional field matching method were superior in normal tissue sparing and dose conformity. However, highly significant volume of low dose associated with IMRT was the main concern for the SC risk. The accumulated LAR for all the critical organs with 3D conformal gap junction and IMRT method was 23-25% while for the 3D conformal field matching method it was 21%. Conclusion: The LAR associated with the institutional field matching technique was substantially lower. As this method is highly robust and easy to set up, it can be a better choice of a craniospinal irradiation technique where 3DCRT is the only choice of treatment.