Related Experiment Video
Updated: May 10, 2026
08:34
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
20.3K
Correlation Between Dosimetric Parameters and Local Control in Definitive Radiotherapy for Head and Neck Cancers
Mikiko Yamashita1,2, Shingo Ohira2,3, Hiroaki Tanabe4
1Department of Radiological Technology, Kobe City Medical Center General Hospital, Hyogo, Japan; m-yamashita@kcho.jp.
In Vivo (Athens, Greece)
|February 28, 2024
Summary
Accurate radiotherapy dose to the gross tumor volume (GTV) is crucial for local control in head and neck cancers. Precise dose evaluation, including D99% and Dmin, helps predict treatment response and identify areas needing verification in treatment planning.
Area of Science:
- Radiation oncology
- Medical physics
- Oncology
Background:
- Radiotherapy (RT) outcomes for head and neck (H&N) cancers are typically assessed by stage, patient factors, and chemotherapy.
- Local control in definitive RT for H&N cancers is influenced by the prescribed dose to the gross tumor volume (GTV) and the calculation algorithm used.
Purpose of the Study:
- To investigate the impact of prescribed dose to the GTV and calculation algorithms on local control in definitive RT for H&N cancers.
- To analyze dose evaluation parameters using follow-up imaging after RT.
Main Methods:
- 154 H&N cancer patients treated with Volumetric Modulated Arc Therapy were analyzed.
- Patients were categorized into responders and non-responders based on follow-up images.
- Dose evaluation parameters (Dmax, D1%, D50%, D99%, Dmin) to the GTV were compared between groups.
Main Results:
- Dose to 99% of the GTV (D99%) showed significant differences between local failure and responders, and between local failure and non-responders.
- Minimum dose (Dmin) to the GTV differed significantly between responders and non-responders, and between responders and local failure.
Conclusions:
- Verifying dose distribution across all treatment planning slices is essential.
- Precise assessment of the GTV dose is critical for optimizing local control in H&N cancer radiotherapy.
More Related Videos
Related Concept Videos
01:15Drug Dosage Regimen: Overview
A drug dosage regimen describes the specific instructions and schedule for administering a drug to a patient. It considers factors such as drug dosage, frequency, route of administration, and duration of treatment. Designing an appropriate dosage regimen for a patient aims to achieve a target drug concentration at the site of action.
Typically, the starting dose and dosing interval are guided by the manufacturer's recommendations based on clinical trials conducted during and after drug...
Typically, the starting dose and dosing interval are guided by the manufacturer's recommendations based on clinical trials conducted during and after drug...
01:01Dosage Regimens: Partial Pharmacokinetic Parameters
It is not uncommon for complete drug pharmacokinetic profiles to remain elusive in pharmacokinetics. This necessitates certain educated assumptions by pharmacokineticists to determine appropriate dosage regimens without comprehensive pharmacokinetic data from animal or human studies. One prevalent assumption is setting the bioavailability factor, denoted as F, to 1 or 100%. This assumption caters to the scenario where a drug doesn't achieve full systemic absorption, resulting in the patient...
01:21Dose Size and Dosing Frequency: Determination Methods
Determining the optimal dose size and dosing frequency in pharmacotherapy is crucial for achieving therapeutic effectiveness while minimizing adverse effects. This article explores the methodologies employed in determining these parameters, focusing on their significance and interplay to tailor dosing regimens.Dose Size: Dose size refers to the amount of a drug administered in a single dose. It is determined based on the drug's pharmacodynamics and pharmacokinetics properties and...
01:15Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations
Gentamicin, an aminoglycoside antibiotic, is commonly administered via intermittent intravenous infusion to treat severe infections. An intermittent one-hour infusion of gentamicin, administered at eight-hour intervals, allows for precise control of plasma drug concentrations, minimizing toxicity while ensuring therapeutic efficacy. Pharmacokinetic principles govern the dynamics of plasma concentrations and can be mathematically described using specific equations.The plasma drug concentration...
01:25Determination of Multiple Dosing Parameters: Loading and Maintenance Doses
A loading dose is an essential pharmacological strategy to rapidly achieve the target plasma drug concentration necessary for an immediate therapeutic effect. This approach is especially critical for drugs characterized by slow absorption or extended half-lives, where delaying therapeutic plasma levels could compromise treatment outcomes. By administering a loading dose, clinicians ensure a prompt onset of drug action, even for agents with complex pharmacokinetic profiles.Achieving steady-state...
01:25Drug Dosing in Renal Diseases: Dose Adjustments Based on Drug Clearance and Elimination Rate Constant
In patients with renal disease, dosage adjustments are necessary to maintain therapeutic plasma drug concentrations and prevent toxicity or subtherapeutic exposure. Renal impairment alters drug pharmacokinetics, especially in conditions like uremia, where changes such as prolonged elimination half-life and altered apparent volume of distribution can significantly affect drug disposition. These changes require careful modification of the dosing regimen to achieve the desired clinical...