Related Experiment Video
Updated: Aug 9, 2026
10:35
Stereotactic Radiosurgery for Gynecologic Cancer
Published on: April 17, 2012
18.3K
Tissue spacers in brachytherapy: A systematic review and meta-analysis
Mohammad Hossein Sadeghi1, Zahra Siavashpour2, Sedigheh Sina3
1Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
Critical Reviews in Oncology/Hematology
|June 4, 2025
Summary
Tissue spacers significantly reduce radiation dose to organs at risk (OARs) in brachytherapy, lowering toxicity and improving outcomes. This systematic review supports their integration into standard clinical practice for better patient quality of life.
Area of Science:
- Medical Physics
- Radiation Oncology
- Clinical Research
Background:
- Brachytherapy is a crucial cancer treatment, but radiation dose to nearby organs at risk (OARs) can cause toxicity.
- Tissue spacers are used to increase the distance between the radiation source and OARs, potentially improving treatment safety.
Purpose of the Study:
- To systematically evaluate the impact of tissue spacers on OAR radiation dose reduction.
- To assess the effect of spacers on treatment-related toxicity and clinical outcomes in brachytherapy.
- To synthesize evidence following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
Main Methods:
- A comprehensive literature search was performed across major databases (PubMed, Scopus, etc.) from 1990-2024.
- Eligible studies included randomized trials, cohort studies, and dosimetric analyses of brachytherapy with spacers.
- Meta-analyses were conducted on quantitative data from at least three studies using random-effects models.
Main Results:
- Spacers consistently reduced rectal dose (15-50%) and gastrointestinal toxicity in prostate brachytherapy.
- In head and neck cancers, spacers lowered jaw dose and reduced osteoradionecrosis rates.
- Gynecologic brachytherapy showed 10-20% dose reductions in bladder/rectal OARs, with no compromise in tumor coverage and fewer late complications.
Conclusions:
- Tissue spacers significantly improve the therapeutic ratio in brachytherapy by reducing OAR doses and associated toxicities.
- Evidence supports integrating spacers into standard brachytherapy practice.
- Further randomized trials are needed to optimize spacer design, techniques, and cost-effectiveness.
Related Concept Videos
01:13Mass Analyzers: Overview
The mass analyzer is a crucial component of the mass spectrometer. In the ionization chamber, the vaporized sample is bombarded with a high-energy electron beam to generate a radical cation and further fragment into neutral molecules, radicals, and cations. A series of negatively charged accelerator plates accelerate the cations into the mass analyzer. The mass analyzer separates ions according to their mass-to-charge (m/z) ratios and then directs them to the detector. The common types of mass...
01:19Mass Analyzers: Common Types
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...
01:25Atomic Absorption Spectroscopy: Interference
Interference leads to systematic error in atomic absorption (AA) measurements by enhancing or diminishing the analytical signal or the background. These interferences can be grouped into three main categories: spectral interference, chemical interference, and physical interference.
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
01:25Elements of Block Diagrams
Block diagrams serve as a visual representation of the input-output relationships within a system. An illustrative example is a heating system, where the set temperature activates the furnace to warm the room to the desired level. Block diagrams are versatile, modeling linear systems through Laplace transform variables and nonlinear systems using time domain variables.
A block diagram typically includes essential elements such as comparators, blocks, and feedback loops. Each of these elements...
A block diagram typically includes essential elements such as comparators, blocks, and feedback loops. Each of these elements...
01:22Block Diagram Reduction
The process of deriving the transfer function of a control system often involves reducing its block diagram to a single block. This simplification can be achieved through a series of strategic operations, including relocating branch points and comparators. These operations preserve the overall function of the system while allowing for easier manipulation and combination of blocks.
The first step in this process is the identification and relocation of a branch point. A branch point, where a...
The first step in this process is the identification and relocation of a branch point. A branch point, where a...
01:20Mason's Rule
Mason's rule is a powerful tool in control systems and signal processing. It simplifies the calculation of transfer functions from signal-flow graphs. This method leverages various elements, including loop gains, forward-path gains, and non-touching loops, to determine the transfer function efficiently.
Loop gain is determined by identifying and tracing a path from a node back to itself. This involves computing the product of branch gains along the loop. Each loop's gain is crucial for further...
Loop gain is determined by identifying and tracing a path from a node back to itself. This involves computing the product of branch gains along the loop. Each loop's gain is crucial for further...