Dosimetric comparison of short and full arc in spinal PTV in volumetric-modulated arc therapy-based craniospinal irradiation

Sarkar, Biplab; Munshi, Anusheel; Ganesh, T; Manikandan, A.; Mohanti, Bidhu Kalyan

doi:10.1016/j.meddos.2019.03.003

Cited by 15 publications

(19 citation statements)

References 17 publications

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“…While most CSI literature concentrated on dosimetric considerations of CSI, we report a novel approach of technique modification with the aim to improve planning and treatment efficiency. A review of recent literature showed that CSI treatment in the supine position using VMAT technique is the method of choice due to accessibility, stability, improved dose conformity and reduced OAR dose 1,2,5–8,11,13,14 . There are studies which mention treatment time differences between 3DCRT, IMRT and VMAT 2,15,16 where all agreed VMAT would require longer treatment time.…”

Section: Discussionmentioning

confidence: 99%

“…The planning target volume (PTV) extends from the vertex of the skull to the sacral region, and fields are matched at the junction region, from the posterior skin surface to adequately cover and treat the entire PTV 1–3 . Various publications have explored ways to use intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) to improve plan conformity and reduce dose to organ at risk (OAR) such as optic structures, brainstem, heart and kidneys 1–11 …”

Section: Introductionmentioning

confidence: 99%

“…Cranial-spinal irradiation (CSI) is a complex radiotherapy technique due to the need to irradiate the entire craniospinal axis for patients with high-risk cerebrospinal fluid involvement. [1][2][3][4][5][6][7][8][9][10][11] The planning target volume (PTV) extends from the vertex of the skull to the sacral region, and fields are matched at the junction region, from the posterior skin surface to adequately cover and treat the entire PTV. [1][2][3] Various publications have explored ways to use intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) to improve plan conformity and reduce dose to organ at risk (OAR) such as optic structures, brainstem, heart and kidneys.…”

Section: Introductionmentioning

confidence: 99%

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Modified volumetric modulated arc therapy technique with reduced planning and treatment time for craniospinal irradiation utilising two isocentres

Nguyen

Dang

Deegan

et al. 2022

J of Medical Radiation Sci

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Introduction: Paediatric patients (individuals below 18 years of age) requiring cranial-spinal irradiation (CSI) at our institution are commonly planned and treated using a three isocentre (3-ISO) volumetric modulated arc therapy (VMAT) technique. A modified two isocentre (2-ISO) VMAT technique was investigated with the aim to improve workflow and reduce planning and treatment time. Methods: Five CSI paediatric patients previously treated with a 3-ISO VMAT technique were retrospectively replanned using a 2-ISO VMAT technique. The 2-ISO VMAT plans were reviewed and approved by a radiation oncologist (RO) before undergoing patient-specific quality assurance (QA) procedures, performed by a radiation oncology medical physicist (ROMP). Planning target volume (PTV) coverage, organ-at-risk (OAR) dose as well as planning and treatment durations of the first five patients utilising 2-ISO technique were compared with 3-ISO technique. Results: The average percentage difference in PTV coverage by 95% reference dose between the 2-ISO and 3-ISO is 0.14%, and the average difference in OAR median dose is 0.68 Gy. Conformity and homogeneity indices have the same averages at 1.18 and 0.4 respectively. Patient-specific physics QA results were all comparable with the 3-ISO averages at 98.84% and the 2-ISO at 98.71%. Planning duration for the 2-ISO was reduced by up to 75%, and daily treatment duration was reduced by up to 50%. Of all the previously treated CSI patients using a 3-ISO technique, 45% were suitable for the 2-ISO technique. Conclusion: The 2-ISO VMAT technique provided comparable dose distribution based on PTV coverage, OAR dose and plan metric indices. Reduced planning and treatment duration with the 2-ISO technique facilitated improved workflow with decreased sedation time for paediatric patients requiring a general anaesthesia.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modified volumetric modulated arc therapy technique with reduced planning and treatment time for craniospinal irradiation utilising two isocentres

Nguyen

Dang

Deegan

et al. 2022

J of Medical Radiation Sci

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“…However, our study found that 2 out of 36 patients with medulloblastoma developed frontal lobe metastasis, which was considered as a possible failure of the sieve plate area. With the progress of radiotherapy technology, especially the development of VMAT and TOMO program for the treatment of whole brain and spinal cord technology [11,12], the dose distribution in the target region was more uniform than that of 3DCRT and IMRT.…”

Section: Discussionmentioning

confidence: 99%

Recurrence pattern and Survival analysis in patients undergoing radiotherapy IMRT technique for medulloblastoma

Chang

Wang

et al. 2020

Preprint

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Objective The technique of radiotherapy is associated with the recurrence pattern and prognosis of postoperative treatment for medulloblastoma. Our aim was to assess recurrence patterns and survival in patients with medulloblastoma between three-dimensional conformation (3D-CRT) and intensity modulated radiotherapy (IMRT). To analyze the factors affecting the prognosis, such as the use of 3D-CRT or IMRT, the time interval of surgical and radiotherapy, whether there is chemotherapy and chemotherapy regimen.Methods In this study, 36 patients with medulloblastoma were conducted investigating and data were analyzed from May 2009 to September 2017. The median survival of each group was calculated for different clinical stages,pathological types and treatment methods. The PFS and OS for patients curves were derived by Kaplan-Meier estimation, and which were calculated using the Cox proportional hazards model between the IMRT and 3D-CRT treatment groups.Results Up to the follow-up date, 7 of the 9 patients in the 3D-CRT group had recurrence and 9 of the 27 patients in the IMRT group had recurrence. The 2-year and 5-year PFS of the IMRT group were 74.1% and 65.8%, and which of the 3D-CRT group were 55.6% and 22.2%, respectively. The PFS was significantly higher for patients treated with IMRT compared with 3D-CRT (P<0.05). The 2-year overall survival rates of the IMRT group compared with the 3D-CRT group were the same, the 5-year overall survival rate of the IMRT group was higher than that of the 3D-CRT group, however, there was no statistical difference. The PFS and OS for patients with low-risk groups were better than those of the high-risk group (P<0.05). There was no statistical difference between the M2 group and the M3 group in the 2-year and 5-year OS(P>0.05). There was no statistical difference in the chemotherapy-free group, the EP chemotherapy regimen and the temozolomide (TMZ) chemotherapy group in the 2-year and 5-year PFS and OS(P>0.05). The results of multivariate Cox proportional hazards model analysis showed that the residual, recurrence or metastasis before radiotherapy were independent prognostic factors affecting PFS(P<0.05). Radiotherapy mode was negatively correlated, although there was no statistical significance(P=0.061).Conclusions IMRT can reduce the risk of spinal cord recurrence compared with 3D-CRT, especially the low rate of spinal cord recurrence. The development of the technique of radiotherapy was associated with improvements in medulloblastoma prognosis.

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“…The number of isocenters and their placement was adopted from the VMAT based craniospinal irradiation technique and further improvised for the TMLI technique [12][13][14] Arc per isocenter is not fixed and varies according to the dosimetric requirement. The first two cranial isocenters (covers until mid-neck region) in HFS and all isocenters in FFS have two full arcs; the rest contain two additional partial arcs ( G220 to G140 with avoidance from G300 to G60).…”

Section: Isocentre Placement Strategymentioning

confidence: 99%

Preclinical validation and treatment of volumetric modulated arc therapy based total bone marrow irradiation in Halcyon™ ring gantry linear accelerator

Shahid¹,

Mandal²,

Biswal³

et al. 2022

Radiat Oncol

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Aim This study aims to report preclinical validation, and the first clinical treatment of total bone marrow irradiation (TMI) and total bone marrow and lymph nodal irradiation (TMLI) using Volumetric modulated arc therapy in Halcyon-E ring gantry linear accelerator. Preclinical validation includes simulation, planning, patient-specific QA, and dry run. Material and method Four patients, two female and two male, with body weights of 116 kg, 52 kg, 64 kg, and 62 kg; with two with chronic myeloid leukemia, one each with acute lymphoblastic leukemia and acute myeloid leukemia (AML) were simulated and planned for TMI/TMLI. Patients were immobilized with a full-body vacuum bag. Head first supine (HFS) and Feet first supine (FFS) CT scans were acquired from head to knee and knee to toe. Planning target volume (PTV) was created with a uniform margin of 6 mm over the total bone marrow/bone marrow + lymph nodes. HFS and FFS PTVs were optimized independently using 6MV unflatten energy for 12 Gy in 6 fractions. Plans were merged to create the resultant dose distribution using a junction bias dose matching technique. The total number of isocenters was ≤ 10 per CT set, and two to four full arcs were used for each isocenter. A junction dose gradient technique was used for dose feathering between arcs between adjacent isocenters. Result Only one female patient diagnosed as AML received the TMLI treatment, while the other three patients dropped out due to clinical complications and comorbidities that developed in the time between simulation and treatment. The result presented has been averaged over all four patients. For PTV, 95% dose was normalised to 95% volume, PTV_V107% receiving 3.3 ± 3.1%. Total lung mean and V12Gy were 1048.6 ± 107.1 cGy and 19.5 ± 12.1%. Maximum lens doses were 489.5 ± 35.5 cGy (left: L) and 497 ± 69.2 cGy (right: R). The mean cardiac and bilateral kidney doses were 921.75 ± 89.2 cGy, 917.9 ± 63.2 cGy (L), and 805.9 ± 9.7 cGy (R). Average Monitor Unit was 7738.25 ± 1056.6. The median number of isocenters was 17(HFS+FFS), average MU/Dose (cGy) ratio per isocenter was 2.28 ± 0.3. Conclusion Halcyon-E ring gantry linear accelerator capable of planning and delivering TMI/TMLI.

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Dosimetric comparison of short and full arc in spinal PTV in volumetric-modulated arc therapy-based craniospinal irradiation

Cited by 15 publications

References 17 publications

Modified volumetric modulated arc therapy technique with reduced planning and treatment time for craniospinal irradiation utilising two isocentres

Modified volumetric modulated arc therapy technique with reduced planning and treatment time for craniospinal irradiation utilising two isocentres

Recurrence pattern and Survival analysis in patients undergoing radiotherapy IMRT technique for medulloblastoma

Preclinical validation and treatment of volumetric modulated arc therapy based total bone marrow irradiation in Halcyon™ ring gantry linear accelerator

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