scholarly journals Optimal planning strategy among various arc arrangements for prostate stereotactic body radiotherapy with volumetric modulated arc therapy technique

2017 ◽  
Vol 51 (1) ◽  
pp. 112-120 ◽  
Author(s):  
Sang Won Kang ◽  
Jin Beom Chung ◽  
Jae Sung Kim ◽  
In Ah Kim ◽  
Keun Yong Eom ◽  
...  
Keyword(s):  
Stereotactic Body Radiotherapy ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Biological Metrics ◽  
Significant Difference ◽  
Arc Therapy ◽  
Femoral Heads ◽  
Target Volumes

Abstract Background The aim of this study was to determine the optimal strategy among various arc arrangements in prostate plans of stereotactic body radiotherapy with volumetric modulated arc therapy (SBRT-VMAT). Patients and methods To investigate how arc arrangements affect dosimetric and biological metrics, SBRT-VMAT plans for eighteen patients were generated with arrangements of single-full arc (1FA), single-partial arc (1PA), double-full arc (2FA), and double-partial arc (2PA). All plans were calculated by the Acuros XB calculation algorithm. Dosimetric and radiobiological metrics for target volumes and organs at risk (OARs) were evaluated from dosevolume histograms. Results All plans were highly conformal (CI<1.05, CN=0.91) and homogeneous (HI=0.09-0.12) for target volumes. For OARs, there was no difference in the bladder dose, while there was a significant difference in the rectum and both femoral head doses. Plans using 1PA and 2PA showed a strong reduction to the mean rectum dose compared to plans using 1FA and 2FA. Contrastively, the D2% and mean dose in both femoral heads were always lower in plans using 1FA and 2FA. The average tumor control probability and normal tissue complication probability were comparable in plans using all arc arrangements. Conclusions The use of 1PA had a more effective delivery time and produced equivalent target coverage with better rectal sparing, although all plans using four arc arrangements showed generally similar for dosimetric and biological metrics. However, the D2% and mean dose in femoral heads increased slightly and remained within the tolerance. Therefore, this study suggests that the use of 1PA is an attractive choice for delivering prostate SBRT-VMAT.

scholarly journals Dosimetric comparison between volumetric modulated arc therapy planning techniques for prostate cancer in the presence of intrafractional organ deformation

2020 ◽  
Author(s):  
Maria Varnava ◽  
Iori Sumida ◽  
Michio Oda ◽  
Keita Kurosu ◽  
Fumiaki Isohashi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Normal Tissue Complication Probability ◽  
Conformity Index ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Planning Techniques ◽  
Dose Distributions ◽  
Arc Therapy

Abstract The purpose of this study was to compare single-arc (SA) and double-arc (DA) treatment plans, which are planning techniques often used in prostate cancer volumetric modulated arc therapy (VMAT), in the presence of intrafractional deformation (ID) to determine which technique is superior in terms of target dose coverage and sparing of the organs at risk (OARs). SA and DA plans were created for 27 patients with localized prostate cancer. ID was introduced to the clinical target volume (CTV), rectum and bladder to obtain blurred dose distributions using an in-house software. ID was based on the motion probability function of each structure voxel and the intrafractional motion of the respective organs. From the resultant blurred dose distributions of SA and DA plans, various parameters, including the tumor control probability, normal tissue complication probability, homogeneity index, conformity index, modulation complexity score for VMAT, dose–volume indices and monitor units (MUs), were evaluated to compare the two techniques. Statistical analysis showed that most CTV and rectum parameters were significantly larger for SA plans than for DA plans (P &lt; 0.05). Furthermore, SA plans had fewer MUs and were less complex (P &lt; 0.05). The significant differences observed had no clinical significance, indicating that both plans are comparable in terms of target and OAR dosimetry when ID is considered. The use of SA plans is recommended for prostate cancer VMAT because they can be delivered in shorter treatment times than DA plans, and therefore benefit the patients.

scholarly journals Investigation of whether in-room CT-based adaptive intracavitary brachytherapy for uterine cervical cancer is robust against interfractional location variations of organs and/or applicators

2016 ◽  
Vol 57 (6) ◽  
pp. 677-683 ◽  
Author(s):  
Yoshifumi Oku ◽  
Hidetaka Arimura ◽  
Tran Thi Thao Nguyen ◽  
Yoshiyuki Hiraki ◽  
Masahiko Toyota ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Radiation Treatment ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
Uterine Cervical Cancer ◽  
Intracavitary Brachytherapy ◽  
Conformity Index ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Target Volumes

Abstract This study investigates whether in-room computed tomography (CT)-based adaptive treatment planning (ATP) is robust against interfractional location variations, namely, interfractional organ motions and/or applicator displacements, in 3D intracavitary brachytherapy (ICBT) for uterine cervical cancer. In ATP, the radiation treatment plans, which have been designed based on planning CT images (and/or MR images) acquired just before the treatments, are adaptively applied for each fraction, taking into account the interfractional location variations. 2D and 3D plans with ATP for 14 patients were simulated for 56 fractions at a prescribed dose of 600 cGy per fraction. The standard deviations (SDs) of location displacements (interfractional location variations) of the target and organs at risk (OARs) with 3D ATP were significantly smaller than those with 2D ATP (P &lt; 0.05). The homogeneity index (HI), conformity index (CI) and tumor control probability (TCP) in 3D ATP were significantly higher for high-risk clinical target volumes than those in 2D ATP. The SDs of the HI, CI, TCP, bladder and rectum D2cc, and the bladder and rectum normal tissue complication probability (NTCP) in 3D ATP were significantly smaller than those in 2D ATP. The results of this study suggest that the interfractional location variations give smaller impacts on the planning evaluation indices in 3D ATP than in 2D ATP. Therefore, the 3D plans with ATP are expected to be robust against interfractional location variations in each treatment fraction.

scholarly journals Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Taiki Magome ◽  
Hidetaka Arimura ◽  
Yoshiyuki Shioyama ◽  
Katsumasa Nakamura ◽  
Hiroshi Honda ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Stereotactic Body Radiotherapy ◽  
Similar Case ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
Radiation Absorption ◽  
Conformity Index ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Case Based

Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners.Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP).Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences (P<0.05) in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung.Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT.

Tratamiento del meduloblastoma: comparación entre arcoterapia volumétrica modulada y radioterapia conformada tridimensional

2019 ◽  
pp. 33-46
Author(s):  
Carla Manjón-García ◽  
Virginia Morillo-Macías ◽  
Juan López-Tarjuelo
Keyword(s):  
Conventional Treatment ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Absorbed Dose ◽  
Conformal Radiotherapy ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Arc Therapy ◽  
Target Volumes ◽  
Better Than

Objective: To present the feasibility of the treatment of medulloblastoma with volumetric-modulated arc therapy (VMAT) planned with RayStation for Elekta linacs and compare the results with conventional treatment. Materials and methods: 3 adult patients in prone position treated with 3D-conformal radiotherapy (3DCRT) with 6 MV and 18 MV were replanned with 6 MV VMAT. The dose prescription was 1.8 Gy/fraction. The evaluation of the techniques was carried out with dose-volume histograms and isodoses in target volumes and healthy tissues, and with conformity (CI) and homogeneity (HI) indexes. Results: VMAT CI (0.79 ± 0.02) and HI (0.08 ± 0.02) of the tended to be better than those of 3DCRT (CI = 0.58 ± 0.03 and HI = 0.14 ± 0.07). For healthy tissues, a decrease in the maximum absorbed dose was observed (VMAT: D1% = 1.76 ± 0.04 Gy/fraction and 3DCRT: D1% = 1.93 ± 0.04 Gy/fraction) as well as in the overdoses (VMAT: V107% = 0.05 ± 0.08% and 3DCRT: V107% = 1.0 ± 0.5%). The dosimetric results of organs at risk showed no trend when both techniques were compared. Conclusion: The performance with RayStation of the medulloblastoma treatment by VMAT is viable for Elekta linacs, and a greater coverage, homogeneity and conformation in the target is achieved. Overdoses were also markedly reduced compared with those caused by 3DCRT treatments.

scholarly journals Automated Non-Coplanar VMAT for Dose Escalation in Recurrent Head and Neck Cancer Patients

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1910
Author(s):  
Kaley Woods ◽  
Robert K. Chin ◽  
Kiri A. Cook ◽  
Ke Sheng ◽  
Amar U. Kishan ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Dose Escalation ◽  
Volumetric Modulated Arc Therapy ◽  
Normal Tissue Complication Probability ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Increased Risk ◽  
Recurrent Head

This study evaluates the potential for tumor dose escalation in recurrent head and neck cancer (rHNC) patients with automated non-coplanar volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) planning (HyperArc). Twenty rHNC patients are planned with conventional VMAT SBRT to 40 Gy while minimizing organ-at-risk (OAR) doses. They are then re-planned with the HyperArc technique to match these minimal OAR doses while escalating the target dose as high as possible. Then, we compare the dosimetry, tumor control probability (TCP), and normal tissue complication probability (NTCP) for the two plan types. Our results show that the HyperArc technique significantly increases the mean planning target volume (PTV) and gross tumor volume (GTV) doses by 10.8 ± 4.4 Gy (25%) and 11.5 ± 5.1 Gy (26%) on average, respectively. There are no clinically significant differences in OAR doses, with maximum dose differences of <2 Gy on average. The average TCP is 23% (± 21%) higher for HyperArc than conventional plans, with no significant differences in NTCP for the brainstem, cord, mandible, or larynx. HyperArc can achieve significant tumor dose escalation while maintaining minimal OAR doses in the head and neck—potentially enabling improved local control for rHNC SBRT patients without increased risk of treatment-related toxicities.

scholarly journals Volumetric Modulated Arc Radiotherapy for Early Stage Non-Small-Cell Lung Carcinoma: Is It Better Than the Conventional Static Beam Intensity Modulated Radiotherapy?

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Vincent Wing Cheung Wu ◽  
Man In Pun ◽  
Cho Pan Lam ◽  
To Wing Mok ◽  
Wah Wai Mok
Keyword(s):  
Early Stage ◽  
Small Cell Lung Carcinoma ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Small Cell ◽  
Small Cell Lung ◽  
Cell Lung Carcinoma ◽  
Intensity Modulated ◽  
Significant Difference ◽  
Arc Therapy

This study compared the performance of volumetric modulated arc therapy (VMAT) techniques: single arc volumetric modulated arc therapy (SA-VMAT) and double arc volumetric modulated arc therapy (DA-VMAT) with the static beam conventional intensity modulated radiotherapy (C-IMRT) for non-small-cell lung carcinoma (NSCLC). Twelve stage I and II NSCLC patients were recruited and their planning CT with contoured planning target volume (PTV) and organs at risk (OARs) was used for planning. Using the same dose constraints and planning objectives, the C-IMRT, SA-VMAT, and DA-VMAT plans were optimized. C-IMRT consisted of 7 static beams, while SA-VMAT and DA-VMAT plans consisted of one and two full gantry rotations, respectively. No significant difference was found among the three techniques in target homogeneity and conformity. Mean lung dose in C-IMRT plan was significantly lower than that in DA-VMAT plan P=0.04. The ability of OAR sparing was similar among the three techniques, with no significant difference in V20, V10, or V5 of normal lungs, spinal cord, and heart. Less MUs were required in SA-VMAT and DA-VMAT. Besides, SA-VMAT required the shortest beam on time among the three techniques. In treatment of early stage NSCLC, no significant dosimetric superiority was shown by the VMAT techniques over C-IMRT and DA-VMAT over SA-VMAT.

Sign in / Sign up

Export Citation Format

Share Document