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Research paper thumbnail of Comparison between volumetric modulated arc therapy based coplanar and noncoplanar planning for stereotactic body radiation therapy of Comparison between Volumetric Modulated arc Therapy based Coplanar and Noncoplanar Planning for Stereotactic Body Radiation Therapy of Liver

Asian Pacific journal of cancer prevention, Apr 1, 2024

Background: The study aims to investigate potential dosimetric benefits between non-coplanar and ... more Background: The study aims to investigate potential dosimetric benefits between non-coplanar and coplanar beam arrangements of Volumetric-Modulated Arc Therapy (VMAT) plans for liver stereotactic body radiotherapy (SBRT). Methods: Thirteen patients who had undergone liver SBRT treatment in our department were chosen retrospectively for the study. Two sets of SBRT-VMAT plans namely, non-coplanar (NC-VMAT) and Coplanar (C-VMAT) were generated in Monaco(v5.11) planning system for Elekta Versa HD Linac using unflatten 6MV photon. The NC-VMAT plans were created by two/three non-coplanar partial arcs with couch rotation of ±15 0 and had an arc span of 130 0 to 160 0 whereas the C-VMAT plans consisted of a full arc. Both plans were compared by statistically analyzing various dosimetric and technical parameters. Results: There is no statistically significant difference observed between the C-VMAT and NC-VMAT plans for planning target volume (PTV) coverage. However, the spine dose (D1cc) was much less in the NC-VMAT plan compared to the C-VMAT plan, with mean values of 6.127 ± 3.08Gy and 9.058 ± 4.76Gy, respectively (p-value=0.002). The low dose spillage to the healthy tissue was compared by the volume receiving 5Gy (V5Gy) and 10Gy (V10Gy). V5Gy of the NC-VMAT plan was 2399.23±1870.76cc while that of C-VMAT plans was 2835.36±1930.20cc with the p-value <0.001. Moreover, the monitor units(MU) were less with NC-VMAT than with C-VMAT SBRT plans (p=0.015). Conclusion: The plan quality of NC-VMAT plans was favorable compared to C-VMAT plans for liver SBRT especially in reducing spine dose, low dose spillage to healthy tissue, and MU.

Research paper thumbnail of Plan Quality Index – An Integrated Dosimetric Approach for Plan Evaluation with Consideration of Quality of Dose Coverage to Tumors and Quality of Organs’ Sparing

Asian Pacific Journal of Cancer Prevention, Sep 1, 2022

Purpose: To find an integrated solution for plan evaluation with multiple dosimetric parameters i... more Purpose: To find an integrated solution for plan evaluation with multiple dosimetric parameters in order to ensure quality of target dose coverage and sparing of organs collectively. Materials and Methods: A mathematical logical expression called Plan Quality Index (PQI) was formulated. It includes two integrated indices 1.Integrated Dosimetric Index for tumor (IDI Tumor) dose coverage and 2.Integrated Dosimetic Index (IDI organs) for Organs At Risk (OARs). PQI was used to select better dosimetric plan form multiple VMAT plans of a Nasopharynx case. In addition, the PQI was used for comparison of VMAT and IMRT plans of 64 patients with Head and Neck cancer. The plan with lesser PQI was considered as a better dosimetric plan. For statistical comparison between two techniques, paired't' and Wilcoxon signed rank test were used with consideration p< 0.05 as a statistically significant. Results: The unambiguous evaluation results with PQI showed that VMAT plan was achieved the entire given dose constraints significantly better than IMRT plan in all the patients (p<0.001). Conclusion: Plan evaluation with PQI can be an unambiguous method. It evaluates the quality of tumor dose coverage (IDITumor) and sparing of OARs (IDI organs) collectively. It enables to change the priority of evaluation criteria of a specified structure based on the clinical requirements. It does not require any specialized program. It can be calculated using ordinary excel program. Using the single value as PQI, the effective determination of a quality plan among many plans can be possible and it can be used for comparison of different techniques.

Research paper thumbnail of Large planning target volume in whole abdomen radiation therapy in ovarian cancers - a comparison between volumetric arc and fixed beam based intensity modulation in ovarian cancers: a comparison between volumetric arc and fixed beam based intensity modulation

Research paper thumbnail of Comparison of Rapid Arc and Intensity-modulated Radiotherapy Plans Using Unified Dosimetry Index and the Impact of Conformity Index on Unified Dosimetry Index Evaluation

Journal of medical physics

The aim of this study was to evaluate the impact of conformity index in the unified dosimetry ind... more The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning techniques namely intensity-modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans, UDI at conformity index one of all plan (UDIunit_CI) score was calculated by assuming conformity index is equal to one. Mean and standard deviations of all indices were calculated. Rapid Arc technique plans of different treatment sites of all patients scored lesser UDI than IMRT plans, and the conformity index of Rapid Arc plan was significantly better than IMRT plan. The average dose gradient, homogeneity, coverage, and conformity index of all sites with Rapid Arc plans were 0.212 ± 0.05, 1.123 ± 0.03, 0.959 ± 0.03, and 1.056 ± 0.09; with IMRT plans were 0.190 ± 0.05, 1.113 ± 0.04, 0...

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 2015

Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding wi... more Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.

Research paper thumbnail of Evaluation of healthy tissue dose at different regions between volumetric-modulated arc therapy and intensity-modulated radiation therapy plans in the treatment of various cancers

Journal of Medical Physics, 2019

Background: Radiotherapy plays an important role in the management of cancer. Although the improv... more Background: Radiotherapy plays an important role in the management of cancer. Although the improved technologies increase therapeutic index, different delivery techniques deliver different dose pattern to the healthy tissue within and outside treatment volume. Objective: The objective of this study was to evaluate the low, intermediate, and high dose to healthy tissue within and outside the treatment volume and to find the relation between tumor volume and various doses received healthy tissue volume. Materials and Methods: A total of 150 patients were included. For all patients, planning computed tomography images were acquired. Tumors, critical structures, and healthy tissue volumes at different regions were delineated. Two sets of plans, one with volumetric-modulated arc therapy and another with intensity-modulated radiation therapy (IMRT) were created, optimized for 6 MV photons and dose was calculated. Dosimetry results for tumor, organs at risks (OARs), and healthy tissue from both the techniques were evaluated and compared. Results: Tumor coverage and dose to OARs was significantly better with volumetric-modulated arc therapy (VMAT). Volume of healthy tissue received high-dose within the treatment volume as well as volume of healthy tissue received low and intermediate-dose out of treatment volume were significantly (P < 0.002) lesser with VMAT. Besides, the results showed that as the tumor volume increased, the various dose received healthy tissue volume also increased. Conclusions: VMAT plan can reduce the risk of secondary malignancy while treating different sites of cancer. VMAT is the most appropriate technique than IMRT, especially in the treatment of large tumor volume. Special attention has to be given, especially while treating women and children.

Research paper thumbnail of Higher Homogeneity Index in Close Proximity Targets with Different Dose Prescription with Vmat Compare to Imrt

Research paper thumbnail of Comparison of Rapid Arc and Intensity‑modulated Radiotherapy Plans Using Unified Dosimetry Index and the Impact of Conformity Index on Unified Dosimetry Index Evaluation

Medknow, 2017

The aim of this study was to evaluate the impact of conformity index in the unified dosimetry ind... more The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning
techniques namely intensity‑modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and
compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans,
UDI at conformity index one of all plan (UDIunit_CI) score was calculated by assuming conformity index is equal to one. Mean and standard
deviations of all indices were calculated. Rapid Arc technique plans of different treatment sites of all patients scored lesser UDI than IMRT
plans, and the conformity index of Rapid Arc plan was significantly better than IMRT plan. The average dose gradient, homogeneity, coverage,
and conformity index of all sites with Rapid Arc plans were 0.212 ± 0.05, 1.123 ± 0.03, 0.959 ± 0.03, and 1.056 ± 0.09; with IMRT plans
were 0.190 ± 0.05, 1.113 ± 0.04, 0.950 ± 0.04, and 1.172 ± 0.16, respectively. UDI score value with actual conformity index of Rapid Arc
and IMRT plans differed significantly (P < 0.001). However, UDIunit_CI score values with assumed conformity index equal to one did not differ
significantly (P = 0.528). In the comparison of IMRT and Rapid Arc plans using the UDI score, the impact of conformity index was significant.

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

Scientific Research, 2015

This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in... more This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding
window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two
dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal
fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients
and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of
all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse
treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of
Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p
= 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of
lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy
was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy),
right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ±
7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p <
0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique
was superior to IMRT in sparing the OARs without compromising target coverage and delivered
the plan with lesser monitor unit and treatment time.

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

How to cite this paper: Krishnan, J., et al. (2015) A Dosimetric Comparison of Double Arc Volumet... more How to cite this paper: Krishnan, J., et al. (2015) A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 4, 353-363. http://dx. Abstract Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.

Research paper thumbnail of Comparison between volumetric modulated arc therapy based coplanar and noncoplanar planning for stereotactic body radiation therapy of Comparison between Volumetric Modulated arc Therapy based Coplanar and Noncoplanar Planning for Stereotactic Body Radiation Therapy of Liver

Asian Pacific journal of cancer prevention, Apr 1, 2024

Background: The study aims to investigate potential dosimetric benefits between non-coplanar and ... more Background: The study aims to investigate potential dosimetric benefits between non-coplanar and coplanar beam arrangements of Volumetric-Modulated Arc Therapy (VMAT) plans for liver stereotactic body radiotherapy (SBRT). Methods: Thirteen patients who had undergone liver SBRT treatment in our department were chosen retrospectively for the study. Two sets of SBRT-VMAT plans namely, non-coplanar (NC-VMAT) and Coplanar (C-VMAT) were generated in Monaco(v5.11) planning system for Elekta Versa HD Linac using unflatten 6MV photon. The NC-VMAT plans were created by two/three non-coplanar partial arcs with couch rotation of ±15 0 and had an arc span of 130 0 to 160 0 whereas the C-VMAT plans consisted of a full arc. Both plans were compared by statistically analyzing various dosimetric and technical parameters. Results: There is no statistically significant difference observed between the C-VMAT and NC-VMAT plans for planning target volume (PTV) coverage. However, the spine dose (D1cc) was much less in the NC-VMAT plan compared to the C-VMAT plan, with mean values of 6.127 ± 3.08Gy and 9.058 ± 4.76Gy, respectively (p-value=0.002). The low dose spillage to the healthy tissue was compared by the volume receiving 5Gy (V5Gy) and 10Gy (V10Gy). V5Gy of the NC-VMAT plan was 2399.23±1870.76cc while that of C-VMAT plans was 2835.36±1930.20cc with the p-value <0.001. Moreover, the monitor units(MU) were less with NC-VMAT than with C-VMAT SBRT plans (p=0.015). Conclusion: The plan quality of NC-VMAT plans was favorable compared to C-VMAT plans for liver SBRT especially in reducing spine dose, low dose spillage to healthy tissue, and MU.

Research paper thumbnail of Plan Quality Index – An Integrated Dosimetric Approach for Plan Evaluation with Consideration of Quality of Dose Coverage to Tumors and Quality of Organs’ Sparing

Asian Pacific Journal of Cancer Prevention, Sep 1, 2022

Purpose: To find an integrated solution for plan evaluation with multiple dosimetric parameters i... more Purpose: To find an integrated solution for plan evaluation with multiple dosimetric parameters in order to ensure quality of target dose coverage and sparing of organs collectively. Materials and Methods: A mathematical logical expression called Plan Quality Index (PQI) was formulated. It includes two integrated indices 1.Integrated Dosimetric Index for tumor (IDI Tumor) dose coverage and 2.Integrated Dosimetic Index (IDI organs) for Organs At Risk (OARs). PQI was used to select better dosimetric plan form multiple VMAT plans of a Nasopharynx case. In addition, the PQI was used for comparison of VMAT and IMRT plans of 64 patients with Head and Neck cancer. The plan with lesser PQI was considered as a better dosimetric plan. For statistical comparison between two techniques, paired't' and Wilcoxon signed rank test were used with consideration p< 0.05 as a statistically significant. Results: The unambiguous evaluation results with PQI showed that VMAT plan was achieved the entire given dose constraints significantly better than IMRT plan in all the patients (p<0.001). Conclusion: Plan evaluation with PQI can be an unambiguous method. It evaluates the quality of tumor dose coverage (IDITumor) and sparing of OARs (IDI organs) collectively. It enables to change the priority of evaluation criteria of a specified structure based on the clinical requirements. It does not require any specialized program. It can be calculated using ordinary excel program. Using the single value as PQI, the effective determination of a quality plan among many plans can be possible and it can be used for comparison of different techniques.

Research paper thumbnail of Large planning target volume in whole abdomen radiation therapy in ovarian cancers - a comparison between volumetric arc and fixed beam based intensity modulation in ovarian cancers: a comparison between volumetric arc and fixed beam based intensity modulation

Research paper thumbnail of Comparison of Rapid Arc and Intensity-modulated Radiotherapy Plans Using Unified Dosimetry Index and the Impact of Conformity Index on Unified Dosimetry Index Evaluation

Journal of medical physics

The aim of this study was to evaluate the impact of conformity index in the unified dosimetry ind... more The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning techniques namely intensity-modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans, UDI at conformity index one of all plan (UDIunit_CI) score was calculated by assuming conformity index is equal to one. Mean and standard deviations of all indices were calculated. Rapid Arc technique plans of different treatment sites of all patients scored lesser UDI than IMRT plans, and the conformity index of Rapid Arc plan was significantly better than IMRT plan. The average dose gradient, homogeneity, coverage, and conformity index of all sites with Rapid Arc plans were 0.212 ± 0.05, 1.123 ± 0.03, 0.959 ± 0.03, and 1.056 ± 0.09; with IMRT plans were 0.190 ± 0.05, 1.113 ± 0.04, 0...

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 2015

Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding wi... more Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.

Research paper thumbnail of Evaluation of healthy tissue dose at different regions between volumetric-modulated arc therapy and intensity-modulated radiation therapy plans in the treatment of various cancers

Journal of Medical Physics, 2019

Background: Radiotherapy plays an important role in the management of cancer. Although the improv... more Background: Radiotherapy plays an important role in the management of cancer. Although the improved technologies increase therapeutic index, different delivery techniques deliver different dose pattern to the healthy tissue within and outside treatment volume. Objective: The objective of this study was to evaluate the low, intermediate, and high dose to healthy tissue within and outside the treatment volume and to find the relation between tumor volume and various doses received healthy tissue volume. Materials and Methods: A total of 150 patients were included. For all patients, planning computed tomography images were acquired. Tumors, critical structures, and healthy tissue volumes at different regions were delineated. Two sets of plans, one with volumetric-modulated arc therapy and another with intensity-modulated radiation therapy (IMRT) were created, optimized for 6 MV photons and dose was calculated. Dosimetry results for tumor, organs at risks (OARs), and healthy tissue from both the techniques were evaluated and compared. Results: Tumor coverage and dose to OARs was significantly better with volumetric-modulated arc therapy (VMAT). Volume of healthy tissue received high-dose within the treatment volume as well as volume of healthy tissue received low and intermediate-dose out of treatment volume were significantly (P < 0.002) lesser with VMAT. Besides, the results showed that as the tumor volume increased, the various dose received healthy tissue volume also increased. Conclusions: VMAT plan can reduce the risk of secondary malignancy while treating different sites of cancer. VMAT is the most appropriate technique than IMRT, especially in the treatment of large tumor volume. Special attention has to be given, especially while treating women and children.

Research paper thumbnail of Higher Homogeneity Index in Close Proximity Targets with Different Dose Prescription with Vmat Compare to Imrt

Research paper thumbnail of Comparison of Rapid Arc and Intensity‑modulated Radiotherapy Plans Using Unified Dosimetry Index and the Impact of Conformity Index on Unified Dosimetry Index Evaluation

Medknow, 2017

The aim of this study was to evaluate the impact of conformity index in the unified dosimetry ind... more The aim of this study was to evaluate the impact of conformity index in the unified dosimetry index (UDI) score for two different planning
techniques namely intensity‑modulated radiotherapy (IMRT) and Rapid Arc. Rapid Arc and IMRT plans of 57 patients were evaluated and
compared using UDI score which incorporates four indices. To determine the impact of conformity index on the IMRT and Rapid Arc plans,
UDI at conformity index one of all plan (UDIunit_CI) score was calculated by assuming conformity index is equal to one. Mean and standard
deviations of all indices were calculated. Rapid Arc technique plans of different treatment sites of all patients scored lesser UDI than IMRT
plans, and the conformity index of Rapid Arc plan was significantly better than IMRT plan. The average dose gradient, homogeneity, coverage,
and conformity index of all sites with Rapid Arc plans were 0.212 ± 0.05, 1.123 ± 0.03, 0.959 ± 0.03, and 1.056 ± 0.09; with IMRT plans
were 0.190 ± 0.05, 1.113 ± 0.04, 0.950 ± 0.04, and 1.172 ± 0.16, respectively. UDI score value with actual conformity index of Rapid Arc
and IMRT plans differed significantly (P < 0.001). However, UDIunit_CI score values with assumed conformity index equal to one did not differ
significantly (P = 0.528). In the comparison of IMRT and Rapid Arc plans using the UDI score, the impact of conformity index was significant.

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

Scientific Research, 2015

This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in... more This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding
window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two
dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal
fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients
and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of
all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse
treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of
Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p
= 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of
lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy
was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy),
right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ±
7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p <
0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique
was superior to IMRT in sparing the OARs without compromising target coverage and delivered
the plan with lesser monitor unit and treatment time.

Research paper thumbnail of A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer

How to cite this paper: Krishnan, J., et al. (2015) A Dosimetric Comparison of Double Arc Volumet... more How to cite this paper: Krishnan, J., et al. (2015) A Dosimetric Comparison of Double Arc Volumetric Modulated Arc Therapy with Large Field Intensity Modulated Radiation Therapy for Head and Neck Cancer. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 4, 353-363. http://dx. Abstract Background: This Study Evaluate two state of Art techniques, Rapid Arc and large-field sliding window IMRT in terms of dosimetric end points and delivery time for head and neck cancer. Materials and Methods: 22 patients with head and neck cancer were selected for a planning comparative study. All patients went to CT-simulation in supine position. PTVs were delineated for two dose level of prescription 70 Gy to the boost-PTV70Gy and 54 Gy to the elective-PTV54Gy in 35 equal fraction/day. Simultaneous Integrated Boost (SIB) technique plan was generated for all patients and optimized with both techniques, Rapid Arc and IMRT with similar planning objectives. Dose of all plans of both techniques were calculated for 6MV photon using AAA implemented in Eclipse treatment planning system (10.0.39) with calculating grid size of 2.5 mm. Results: Comparison of Rapid Arc and IMRT plans in every patient showed significantly higher conformity index (CI95%) (p = 0.021) and sparing of the all OARs with Rapid Arc. The average homogeneity Index (HI95%) of lower prescribed dose target PTV54Gy which is in proximity to Higher dose prescribed target PTV70Gy was improved significantly with rapid Arc (p = 0.0001). D1% of spinal cord dose reduced significantly (p = 0.047) with Rapid Arc and the average mean dose of both left-parotid (21.26 ± 8.5 Gy), right-parotid (22.37 ± 7.44 Gy) were received lesser than with IMRT (22.78 ± 11.2 Gy and 24.1 ± 7.96 Gy) respectively. A significantly less monitor unit (MU) was required to deliver the plan (p < 0.00001) with significantly lesser treatment time (p < 0.00001). Conclusion: Rapid Arc technique was superior to IMRT in sparing the OARs without compromising target coverage and delivered the plan with lesser monitor unit and treatment time.