Related Experiment Video
Updated: Mar 2, 2026
06:13
Stepwise Dosing Protocol for Increased Throughput in Label-Free Impedance-Based GPCR Assays
Published on: February 21, 2020
7.1K
SU-E-T-250: Dose-Response Curves for the Esophagus
Medical Physics
|May 19, 2017
Summary
Radiation therapy for esophageal cancer causes the esophagus to thicken, with an average 30% increase in size by the end of treatment. This esophageal expansion, measured using 4D CT scans, shows significant patient variability.
Area of Science:
- Radiation oncology
- Medical imaging
- Esophageal cancer treatment
Background:
- Radiation therapy for esophageal cancer can cause side effects.
- Esophageal thickening is a potential indicator of radiation injury.
- Understanding dose-response relationships is crucial for optimizing treatment.
Purpose of the Study:
- To establish the dose-response curve for esophageal radiation injury.
- To use esophageal thickening on 4D CT scans as a surrogate for radiation damage.
Main Methods:
- 15 esophageal cancer patients undergoing concurrent chemoradiotherapy (50.4Gy) were analyzed.
- Weekly 4D CT scans were used to track changes in esophageal size.
- Deformable image registration mapped esophageal contours to assess cross-sectional area changes.
Main Results:
- Esophageal expansion increased progressively throughout treatment.
- All patients showed increased esophageal thickness by the final week.
- Average relative esophageal expansion was 1.30±0.19, with 7/15 patients exceeding 1.3.
Conclusions:
- The esophagus demonstrates significant expansion in response to radiation therapy.
- A ~30% increase in esophageal cross-sectional area is observed by the end of a 50.4Gy treatment.
- Patient-specific variability in esophageal response to radiation is notable.
Keywords:
CancerComputed tomographyDosimetryImage registrationIntensity modulated radiation therapyMedical imagingMedical treatment planningRadiation treatmentMore Related Videos
07:32Isolating and Using Sections of Bovine Mesenteric Artery and Vein as a Bioassay to Test for Vasoactivity in the Small Intestine
Published on: October 7, 2014
10.1K
08:41Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues
Published on: June 3, 2019
10.4K
Related Concept Videos
01:21Dose Response Curve: Conventional Versus Nonmonotonic
128
The correlation between a drug's dosage and its impact on a biological system is a cornerstone of pharmacology and toxicology. Conventional dose–response curves, which include graded and quantal relationships, are key to this understanding. Graded dose–response curves depict the spectrum of a biological reaction to different doses within an individual, indicating that as the drug dosage increases, so does the intensity of the response. On the other hand, quantal dose–response...
128
01:03Dose-Response Relationship: Overview
5.4K
Agonists can bind with and activate receptors, resulting in the formation of drug-receptor complexes. Once formed, these complexes catalyze many biochemical processes at the cellular level and subsequently induce a pharmacologic response. The degree of response is directly proportional to the fraction of activated receptors, which in turn, depends on the concentration of the drug at the receptor site as well as the sensitivity of the receptor. An increase in the administered dose contributes to...
5.4K
01:22Dose-Response Relationship: Potency and Efficacy
6.9K
The potency of a drug is the measure of its ability to produce a biological response and can be compared by looking at the half-maximum effective concentration or EC50 values of different drugs. A lower EC50 value indicates higher potency of the drug. In the dose–response curve of two antihypertensive drugs, candesartan and irbesartan, a significant difference is observed in their EC50 values. A lower EC50 value for candesartan indicates that it is more potent than irbesartan, as it...
6.9K
01:28Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect
68
A drug’s dosage and pharmacokinetic properties determine how quickly it acts, how intense its effects are, and how long it lasts. Higher doses increase drug concentration at receptor sites, producing a hyperbolic curve when pharmacologic response is plotted against drug dose. Converting this scale to a log-linear format results in a sigmoidal curve, better representing dose–response relationships.For drugs following a one-compartment model, the pharmacologic response is directly...
68
01:25Dose-Response Relationship: Selectivity and Specificity
10.2K
Drugs exert their therapeutic effects by interacting with receptors, enzymes, or ion channels that are present throughout the human body. The strength and duration of the interaction between a drug and its target receptor are characterized by the selectivity and specificity of the drug. Selectivity refers to a drug's strong preference for its intended target over other targets. For instance, isoprenaline, a non-selective β-adrenergic agonist, interacts with both β1- and...
10.2K
01:24Esophagus
4.2K
The esophagus, a muscular conduit linking the pharynx and stomach, measures roughly 10 inches (25.4 cm) and sits behind the trachea. It remains collapsed when not swallowing. The esophagus follows a predominantly straight path through the thoracic mediastinum and enters the abdominal cavity through a diaphragmatic opening known as the esophageal hiatus.
The movement of edibles from the pharynx into the esophagus is facilitated by the upper esophageal sphincter, which is formed primarily by the...
The movement of edibles from the pharynx into the esophagus is facilitated by the upper esophageal sphincter, which is formed primarily by the...
4.2K