Influence of photon beam energy on IMRT plan quality for radiotherapy of prostate cancer

Solaiappan, Gopi; Ganesan, Singaravelu; Aruna, Prakasarao; Rabbani, B; Supe, Sanjay S.

doi:10.1016/s1507-1367(10)60019-3

Cited by 15 publications

(12 citation statements)

References 30 publications

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“…8,9 Laughlin et al recommended energy of more than 10 MV for treatment of these deep-seated pelvic tumors, especially for larger target volumes or larger patient size, due to significant reduction in integral dose. 10,11 The aim of the present study is to compare the dosimetric effect of different photon energies on conventional fixed field IMRT and dual-rapid arc (DA) and to compare the dosimetric differences between conventional IMRT and DA radiotherapy planning in terms of PTV coverage and doses to OARs.…”

Section: Introductionmentioning

confidence: 99%

Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

Bhushan

Yadav

Tripathi

et al. 2019

ASJO

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Introduction To evaluate the dosimetric effect of photon energies on fixed field intensity-modulated radiotherapy (IMRT) and dual arc (DA) planning and to compare the dosimetric differences between conventional IMRT and DA radiotherapy planning. Materials and Methods IMRT and DA plans were generated for 15 patients having cervical cancer using different photon energies. IMRT and DA plans were generated using seven fields and double arcs, respectively. Dosimetric comparison was done in terms of planning target volume (PTV) coverage, sparing of organ at risk (OAR), homogeneity index (HI), conformity index (CI), and monitor units (MUs). Photo-neutron (energy ≤10MV) contribution was not considered for this study. Near region (NR) and far region (FR) were contoured to evaluate the dose deposited in nontarget area. Results No significant difference was observed (p > 0.05) in PTV coverage for conventional IMRT and DA; however, 6 MV yielded significantly better coverage over 15 MV (p < 0.05) for both the treatment modalities. Mean bladder dose was significantly more for conventional IMRT compared with DA. For rectal mean dose, p-value was nonsignificant for IMRT in comparison to DA, while significant difference was observed for change in photon energies for both treatment modalities respectively, except for 10 MV versus 15 MV DA plans. Significant improvements in HI (except 6 MV vs. 10 MV DA), CI (except 6 MV vs. 10 MV IMRT and DA), MUs, NR, and FR were noted. Conclusion DA generates more conformal, homogenous plans, requires less numbers of MUs, and deposits fewer doses to NR and FR regions of nontarget tissues in comparison to conventional IMRT. Although increase in photon energy for IMRT and DA plans reduces numbers of MUs and dose deposited to NR and FR regions, yet the choice for treatment of carcinoma cervix remains 6 MV due to production of photo-neutrons at higher energies.

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Section: Introductionmentioning

confidence: 99%

Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

Bhushan

Yadav

Tripathi

et al. 2019

ASJO

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“…The authors also came to the conclusion, that chosen beam energy doesn't influence the dose conformity, homogeneity and does not improve normal tissue sparing [5,6]. Their results for the required MU per one fraction, has no sign of statistical significance for both energies, indicating only clinically irrelevant elongations of treatment time with 6 MV compared to the total IMRT treatment time [5].…”

Section: Discussionmentioning

confidence: 96%

Wpływ energii wiązek fotonowych na rozkład dawek dla planów IMRT i VMAT

Radwan¹,

Grządziel²,

Hawrylewicz³

et al. 2014

Nowotwory. Journal of Oncology

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Purpose. Estimation of the difference between photon X-6MV and X-20MV beams for IMRT and VMAT plan's, in respect to dose-volume results and irradiation time (MU). Materials and methods. For each of 74 selected patients four plans, two IMRT with X-6MV & X-20MV beams and two VMAT: X-6MV & X-20MV arcs, were performed. Patients were divided into two groups according to tumor localization: head & neck (H&N) and pelvis. Those localizations were chosen to highlight potential differences regarding the depth of target volume. Each plan was optimized using the same plan objectives and constraints. Plans were compared according to dose-volume results for target and Organs at Risk (OaR's) with Radiation Planning Index (RPI), and beam on time regarding the monitor units (MUs). Results. The mean RPI factor for both technique (IMRT/VMAT) and energies (X-6MV/X-20MV) were similar for H&N region in the range of 0.2310-0.2934 and for the pelvis region the range was 0.3683-0.4007. The difference were not statistically significant (p > 0.05), showing the photon between 6-20 MV, doesn't influence the dose-volume results, for both localization: H&N and pelvis. The mean monitor units in IMRT plans varied from 765 MU to 1116 MU, as in VMAT plans it was from 325 MU to 492 MU. Generally, the number of MU on IMRT technique is greater than MU's in VMAT (difference statistically significant), regardless of the beam energy (X-6MV, X-20MV) and localization (H&N, pelvis). Both techniques; IMRT and VMAT plans with higher photon energy, showed shorter irradiation time (expressed in MU). But, only for pelvic region on VMAT technique, is statistically significant (p = 0.0467). Conclusions. On average, photons beam, between 6-20 MV don't induce significant dose-volume difference. However, higher energy used for planning regions other than head & neck, minimizes the number of MUs and significantly reduces the time of irradiation. Furthermore, reduction of beam on time can be achieved by using VMAT plan rather than IMRT plan. Wpływ energii wiązek fotonowych na rozkład dawek dla planów IMRT i VMATCel. Ocena różnic w planach IMRT i VMAT pomiędzy wiązkami X-6MV i X-20MV w odniesieniu do uzyskanych rozkła-dów dawek oraz czasu napromieniania (MU). Materiały i metody. Na potrzeby porównania wybrano 74 pacjentów, następnie dla każdego obliczono 4 plany: dwa w technice IMRT z wiązkami X-6MV i X-20MV oraz dwa w technice VMAT z łukami X-6MV i X-20MV, uzyskując rozkłady dawek. Pacjentów podzielono na dwie grupy zgodnie z obszarem napromienienia: rejon głowy/szyi oraz rejon miednicy. Lokalizacje zostały wybrane w celu uwidocznienia ewentualnych różnic wynikających z różnych głębokości na których zdefiniowano obszar tarczowy. Każdy plan był optymalizowany z wykorzystaniem z tych samych wytycznych i ograniczeń związanych z obszarami anatomicznymi. Plany zostały następnie porównane pod względem dawek dla obszarów tarczowych i organów krytycznych z użyciem współczynnika RPI (Radiation Planning Index). Następnie porównano czas napromieniania w ujęciu liczby jednostek ...

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“…Also lower energy (6 MV) photon beams was preferred over higher energies (15)(16)(17)(18) in treatment of tumors that abut lung tissue, Wang L et al [18]. Gopi solaiappan et al [19] studied the effect of beam energy on the quality of IMRT plans, all the DVH parameters were analyzed in details. The study recommended the use of 6 MV photons for IMRT of prostate cancer.…”

Section: Discussionmentioning

confidence: 99%

The Dosimetric Effects of Different Beam Energy on Physical Dose Distributions in IMRT Based on Analysis of Physical Indices

Eldesoky¹,

Attalla²,

Elshemey³

2013

JCT

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This work aimed at evaluating the effect of 6-and 10-MV photon energies on intensity-modulated radiation therapy (IMRT) treatment plan outcome in different selected diagnostic cases. For such purpose, 19 patients, with different types of non CNS solid tumers, were selected. Clinical step-and-shoot IMRT treatment plans were designed for delivery on a Siemens Oncor accelerator with 82 leafs; multi-leaf collimators (MLCs). To ensure that the similarity or difference among the plans is due to energy alone, the same optimization constraints were applied for both energy plans. All the parameters like beam angles, number of beams, were kept constant to achieve the same clinical objectives. The Comparative evaluation was based on dose-volumetric analysis of both energy IMRT plans. Both qualitative and quantitative methods were used. Several physical indices for Planning Target Volume (PTV), the relevant Organs at Risk (OARs) as mean dose (Dmean), maximum dose (Dmax), 95% dose (D95), integral dose, total number of segments, and the number of MU were applied. Homogeneity index and conformation number were two other evaluation parameters that were considered in this study. Collectively, the use of 6 MV photons was dosimetrically comparable with 10 MV photons in terms of target coverage, homogeneity, conformity, and OAR savings. While 10-MV plans showed a significant reduction in the number of MUs that varied between 4.2% and 16.6% (P-value = 0.0001) for the different cases compared to 6-MV. The percentage volumes of each patient receiving 2 Gy and 5 Gy were compared for the two energies. The general trend was that 6-MV plans had the highest percentage volume, (P-value = 0.0001, P-value = 0.006) respectively. 10-MV beams actually decreased the integral dose (from average 183.27 ± 152.38 Gy-Kg to 178.08 ± 147.71 Gy-Kg, P-value = 0.004) compared with 6-MV. In general, comparison of the above parameters showed statistically significant differences between 6-MV and 10-MV groups. Based on the present results, the 10-MV is the optimal energy for IMRT, regardless of the concerns about a potential risk of radiation-induced malignancies. It is recommended that the choice to treat at 10 MV be taken as a risk vs. benefit as the clinical significance remains to be determined on case by case basis.

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Influence of photon beam energy on IMRT plan quality for radiotherapy of prostate cancer

Cited by 15 publications

References 30 publications

Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

Wpływ energii wiązek fotonowych na rozkład dawek dla planów IMRT i VMAT

The Dosimetric Effects of Different Beam Energy on Physical Dose Distributions in IMRT Based on Analysis of Physical Indices

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