Use of Flattening Filter-Free Photon Beams in Treating Medulloblastoma: A Dosimetric Evaluation

Pichandi, A.; Mani, Ganesh Kadirampatti; Amalraj, Jerrin; Balaji, K.; Anbumani, Surega

doi:10.1155/2014/769698

Cited by 3 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CSI is a challenging RT technique and require a great care in the radiotherapy planning, delivery and radiation field junction dose verification for optimal results. [4][5][6][7]. In-vivo dosimetry is the recommended procedure to assess and verification of radiation doses during radiotherapy [8][9].…”

mentioning

confidence: 99%

Evaluation of Dosimetric Parameters for Adolescent Craniospinal Irradiation

Verma¹,

Jain²,

Chougule³

2020

IJAR

View full text Add to dashboard Cite

Background: Craniospinal irradiation (CSI) is an important and challenging radiotherapy technique used for the treatment of Medulloblastoma, one of the most common pediatric cancers. Pediatric patients present with wide variability in weight, height, spine length, brain diameter, body size, intra and inter fractional motion depending on their age as compared to adults. These parameters have significant impact on radiation dose delivery to target and normal structures during radiotherapy of pediatric cancer patients. The present study was aimed to evaluate dosimetric parameters and generate plan quality indices for adolescent CSI. Materials and Methods: A 17 years old male adolescent patient with Medulloblastoma was recruited in the present sturdy. The patient was planned with RapidArc TM / Volumetric Modulated Arc Therapy (VMAT) mode using 6 MV X-Ray photon beam from Varian Trilogy with FFF machine. The dose points such as max, mean, 2%, 98%, 95%, 105% and 107% were collected using dose statistics and dose volume histogram (DVH) and analyzed for calculation of various dosimetric parameters. The in-vivo dosimetry was performed and radiation doses to eyes were assessed using CaSO4:Dy TLD powder. Results: The plans were approved with a gamma passing rate (3%, 3mm) of more than 95%. The dose homogeneity index and conformity index were observed 0.074 and 1.10 respectively. The average doses to eyes were observed approximately 35% of the tumor dose during RapidArc TM-CSI. The results of the present study demonstrated that V5 was observed high the normal structures except kidneys. Esophagus and thyroid were receiving significant low dose spillage at a cost of high homogeneity and conformity of dose to PTV which were needed to enhance tumor control probability (TCP) of Medulloblastoma. Conclusion: The present study developed a benchmark guide for adolescent RapidArc TM-CSI.

show abstract

mentioning

confidence: 99%

Evaluation of Dosimetric Parameters for Adolescent Craniospinal Irradiation

Verma¹,

Jain²,

Chougule³

2020

IJAR

View full text Add to dashboard Cite

show abstract

Pediatric Cancers

Million¹,

Axente²

2015

Intensity-Modulated Radiation Therapy

View full text Add to dashboard Cite

Re-irradiating spinal column metastases using IMRT and VMAT with and without flattening filter - a treatment planning study

et al. 2016

View full text Add to dashboard Cite

BackgroundThe aim of this study was to investigate the potential of the flattening filter free (FFF) mode of a linear accelerator for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for patients with in-field recurrence of vertebral metastases.MethodsAn Elekta Synergy Linac with Agility™ head is used to simulate the treatment of ten patients with locally recurrent spinal column metastases. Four plans were generated for each patient treating the vertebrae sparing the spinal cord: Dual arc VMAT and nine field step and shoot IMRT each with and without flattening filter. Plan quality was assessed considering target coverage and sparing of the spinal cord and normal tissue. All plans were verified by a 2D-ionisation-chamber-array, peripheral doses were measured and compared to calculations. Delivery times were measured and compared. The Wilcoxon test was used for statistical analysis with a significance level of 0.05.ResultsTarget coverage, homogeneity index and conformity index were comparable for both flat and flattening filter free beams. The volume of the spinal cord receiving the allowed maximum dose to keep the risk of radiation myelopathy at 0 % was at the same time significantly reduced to below the clinically relevant 1 ccm using FFF mode. In addition the mean dose deposited in the surrounding healthy tissue was significantly reduced in the FFF mode. All four techniques showed equally good gamma scores for plan verification. FFF plans required considerably more MU per fraction dose. Regardless of the large number of MU, out-of-field point dose was significantly lower for FFF plans, with an average reduction of 33 % and mean delivery time was significantly reduced by 22 % using FFF beams. When compared to IMRT FF, VMAT FFF offered even a reduction of 71 % in delivery time and 45 % in peripheral dose.ConclusionsFFF plans showed a significant improvement in sparing of normal tissue and the spinal cord, keeping target coverage and homogeneity comparable. In addition, delivery times were significantly reduced for FFF treatments, minimizing intrafractional motion as well as strain for the patient. Shortest delivery times were achieved using VMAT FFF. For radiotherapy of spinal column metastases VMAT FFF may therefore be considered the preferable treatment option for the combination of Elekta Synergy Linacs and Oncentra® External Beam v4.5 treatment planning system.

show abstract

Use of Flattening Filter-Free Photon Beams in Treating Medulloblastoma: A Dosimetric Evaluation

Cited by 3 publications

References 7 publications

Evaluation of Dosimetric Parameters for Adolescent Craniospinal Irradiation

Evaluation of Dosimetric Parameters for Adolescent Craniospinal Irradiation

Pediatric Cancers

Re-irradiating spinal column metastases using IMRT and VMAT with and without flattening filter - a treatment planning study

Contact Info

Product

Resources

About