open access

Vol 22, No 1 (2017)
Original research articles
Published online: 2017-01-01
Submitted: 2015-11-25
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Dosimetric influence of photon beam energy and number of arcs on volumetric modulated arc therapy in carcinoma cervix: A planning study

Girigesh Yadav, Manindra Bhushan, Abhinav Dewan, Upasna Saxena, Lalit Kumar, Deepika Chauhan, Kothanda Raman, Swarupa Mitra, Mahammood Suhail
DOI: 10.1016/j.rpor.2016.09.002
·
Rep Pract Oncol Radiother 2017;22(1):1-9.

open access

Vol 22, No 1 (2017)
Original research articles
Published online: 2017-01-01
Submitted: 2015-11-25

Abstract

Aim

Aim of the present study was to compare the dosimetric impact of different photon beam energies and number of arcs in the treatment of carcinoma cervix.

Background

Carcinoma cervix is a common cancer in women worldwide with a high morbidity rate. Radiotherapy is used to treat such tumours. Volumetric Modulated Arc Therapy (VMAT) is considered superior to other techniques with multiple arcs and energies.

Materials and methods

Twenty patients with carcinoma cervix underwent radiotherapy in a prospective observation study conducted at our institute. Volumetric modulated arc plans with 6[[ce:hsp sp="0.25"/]]MV, 10[[ce:hsp sp="0.25"/]]MV and 15[[ce:hsp sp="0.25"/]]MV photon energies using single arc (SA) and dual arc (DA) were generated. Several physical indices for planning target volume (PTV) like V95%, V100%, V110%, D98%, D50%, D2% and total number of MUs were compared. Normal Tissue Integral Dose (NTID) and dose to a shell structure PHY2.5 and PHY5.0 were analyzed.

Results

Comparable dose coverage to PTV was observed for all the energies and arcs. CI for DA6MV (1.095) was better than SA6MV (1.127), SA10MV (1.116) and SA15MV (1.116). Evaluated parameters showed significant reduction in OAR doses. Mean bladder dose for DA6MV (41.90[[ce:hsp sp="0.25"/]]Gy) was better than SA6MV (42.48[[ce:hsp sp="0.25"/]]Gy), SA10MV (42.08[[ce:hsp sp="0.25"/]]Gy) and SA15MV (41.93[[ce:hsp sp="0.25"/]]Gy). Similarly, p-value for the mean rectal dose calculated was 0.001 (SA6 vs 15), 0.013 (DA6 vs 10) and 0.003 (DA6 vs 15) and subsequently favoured DA6MV. Difference in NTID was very small.

Conclusions

The study showed no greater advantage of higher energy, and DA VMAT plan with 6[[ce:hsp sp="0.25"/]]MV photon energy was a good choice of treatment for carcinoma cervix as it delivered a highly homogeneous and conformal plan with superior target coverage and better OAR sparing.

Abstract

Aim

Aim of the present study was to compare the dosimetric impact of different photon beam energies and number of arcs in the treatment of carcinoma cervix.

Background

Carcinoma cervix is a common cancer in women worldwide with a high morbidity rate. Radiotherapy is used to treat such tumours. Volumetric Modulated Arc Therapy (VMAT) is considered superior to other techniques with multiple arcs and energies.

Materials and methods

Twenty patients with carcinoma cervix underwent radiotherapy in a prospective observation study conducted at our institute. Volumetric modulated arc plans with 6[[ce:hsp sp="0.25"/]]MV, 10[[ce:hsp sp="0.25"/]]MV and 15[[ce:hsp sp="0.25"/]]MV photon energies using single arc (SA) and dual arc (DA) were generated. Several physical indices for planning target volume (PTV) like V95%, V100%, V110%, D98%, D50%, D2% and total number of MUs were compared. Normal Tissue Integral Dose (NTID) and dose to a shell structure PHY2.5 and PHY5.0 were analyzed.

Results

Comparable dose coverage to PTV was observed for all the energies and arcs. CI for DA6MV (1.095) was better than SA6MV (1.127), SA10MV (1.116) and SA15MV (1.116). Evaluated parameters showed significant reduction in OAR doses. Mean bladder dose for DA6MV (41.90[[ce:hsp sp="0.25"/]]Gy) was better than SA6MV (42.48[[ce:hsp sp="0.25"/]]Gy), SA10MV (42.08[[ce:hsp sp="0.25"/]]Gy) and SA15MV (41.93[[ce:hsp sp="0.25"/]]Gy). Similarly, p-value for the mean rectal dose calculated was 0.001 (SA6 vs 15), 0.013 (DA6 vs 10) and 0.003 (DA6 vs 15) and subsequently favoured DA6MV. Difference in NTID was very small.

Conclusions

The study showed no greater advantage of higher energy, and DA VMAT plan with 6[[ce:hsp sp="0.25"/]]MV photon energy was a good choice of treatment for carcinoma cervix as it delivered a highly homogeneous and conformal plan with superior target coverage and better OAR sparing.

Get Citation

Keywords

Carcinoma cervix; Photon energy; VMAT; Dual arc; Conformity index; NTID

About this article
Title

Dosimetric influence of photon beam energy and number of arcs on volumetric modulated arc therapy in carcinoma cervix: A planning study

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 22, No 1 (2017)

Pages

1-9

Published online

2017-01-01

DOI

10.1016/j.rpor.2016.09.002

Bibliographic record

Rep Pract Oncol Radiother 2017;22(1):1-9.

Keywords

Carcinoma cervix
Photon energy
VMAT
Dual arc
Conformity index
NTID

Authors

Girigesh Yadav
Manindra Bhushan
Abhinav Dewan
Upasna Saxena
Lalit Kumar
Deepika Chauhan
Kothanda Raman
Swarupa Mitra
Mahammood Suhail

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