Purpose: The aim of the current study was to evaluate the backscatter dose and energy spectrum from the Lipiodol with flattening filter (FF) and flattening filter-free (FFF) beams. Moreover, the backscatter range, that was defined as the backscatter distance (BD) are revealed.
Methods: 6 MVX FF and FFF beams were delivered by TrueBeam. Two dose calculation methods with Monte Carlo calculation were used with a virtual phantom in which the Lipiodol (3 × 3 × 3 cm ) was located at a depth of 5.0 cm in a water-equivalent phantom (20 × 20 × 20 cm ). The first dose calculation was an analysis of the dose and energy spectrum with the complete scattering of photons and electrons, and the other was a specified dose analysis only with scattering from a specified region. The specified dose analysis was divided into a scattering of primary photons and a scattering of electrons.
Results: The lower-energy photons contributed to the backscatter, while the high-energy photons contributed the difference of the backscatter dose between the FF and FFF beams. Although the difference in the dose from the scattered electrons between the FF and FFF beams was within 1%, the difference of the dose from the scattered photons between the FF and FFF beams was 5.4% at a depth of 4.98 cm.
Conclusions: The backscatter range from the Lipiodol was within 3 mm and depended on the Compton scatter from the primary photons. The backscatter dose from the Lipiodol can be useful in clinical applications in cases where the backscatter region is located within a tumor.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560232 | PMC |
| http://dx.doi.org/10.1002/acm2.12560 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Comparison between flattening filter and flattening filter-free photon beams in head and neck cancer patients using volumetric modulated arc therapy technique.
Radiat Environ Biophys
January 2025
Radiation Physics, Faculty of Science, Al -Azhar University, Cairo, Egypt.
This study aimed to evaluate the dosimetric and clinical outcomes of flattening filter (FF) versus flattening filter-free (FFF) beams in head and neck cancer (HNC) patients treated with volumetric modulated arc therapy (VMAT). Twenty-four patients with 70/59.4/54 Gy dose prescribed in 33 fractions with simultaneous integrated boost treatment were retrospectively analyzed to compare treatment delivery efficiency, target coverage, sparing of organs at risk (OARs), and remaining volume at risk (RVR) in two HNC groups (nasopharyngeal and oropharyngeal).
View Article and Find Full Text PDFExamination of immunohistochemical of the effects of flattened and unflattened radiotherapy beams in nude mice breast cancer xenografts.
Int J Radiat Biol
January 2025
Department of Neurosurgery, Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey.
Purpose: The aim of this study was to investigate the radiobiological effects underlying the inhibition of breast cancer (BCa) following radiotherapy in nude mice models, and to evaluate the impact of changes in immunohistochemical parameters induced by FF and FFF beams.
Materials And Methods: The study included thirty-six adult nude mouse models, which were randomly assigned to five groups: control (G1), breast cancer (BCa) (G2), FF-400 MU/min (G3), FFF-1100 MU/min (G4), and FFF-1800 MU/min (G5). The control group received neither radiation nor treatment, while the BCa group had a cancer model without radiation.
Correction method for ionization chamber dosimetry in flattening filter free radiotherapy based on Monte Carlo simulation.
Med Phys
December 2024
Division of Ionizing Radiation Metrology, National Institute of Metrology (NIM), Beijing, China.
Background: The clinical use of flattening filter free (FFF) radiotherapy has significantly increased in recent years due to its effective enhancement of dose rates and reduction of scatter dose. A proposal has been made to adjust the incident electron angle of the accelerator to expand the application of FFF beams in areas such as large planning target volumes (PTVs). However, the inherent softening characteristics and non-uniformity of lateral dose distribution in FFF beams inevitably lead to increased dosimetry errors, especially for ionization chambers widely used in clinical practice, which may result in serious accidents during FFF radiotherapy.
View Article and Find Full Text PDFEvaluation of ion recombination and polarity effect on photon depth dose measurements using mini- and micro-ion chamber.
J Appl Clin Med Phys
January 2025
Radiotherapy and Radiosurgery Dept, Humanitas IRCCS Research Hospital and Cancer Center, Milan-Rozzano, Italy.
Purpose: To investigate the effect of ion recombination ( ) and polarity ( ) correction factors on percentage depth dose (PDD) curves for three ion chambers, using flat and flattening filter free (FFF) beams, across different broad field sizes. A method to assess these effects and their corresponding corrections is proposed.
Methods: and were evaluated following the IAEA TRS-398 protocol for three ion chambers: PTW Semiflex-3D-31021, PinPoint-3D-31022, and Semiflex-31010.
RTOG 0915-compliant patient specific QA for lung stereotactic body radiotherapy using the new PTW 1600SRS detector array.
Phys Med
November 2024
Faculty of Informatics & Science, University of Oradea, Oradea 410087, Romania; UniSA Allied Health and Human Performance, University of South Australia, Adelaide, Australia.
Article Synopsis
- The study focuses on improving radiotherapy for oligometastatic lung cancer by proposing a new calibration procedure for the PTW Octavius 1600SRS detector array, specifically in the context of stereotactic body radiation therapy (SBRT) using flattening filter free (FFF) beams.
- The cohort included 20 patients treated with SBRT delivering a total dose of 50 Gy in five fractions, and the calibration method utilized only one factor at a maximum dose rate for the FFF photon beam while ensuring high dosimetric accuracy through the RTOG 0915 protocol.
- Results showed strong clinical outcomes with high gamma passing rates of 98.93% and 99
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!