Optimization for fast-scanning irradiation in particle therapy.

Med Phys

Medical Physics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.

Published: August 2007

In three-dimensional irradiation with pencil beam scanning, an extra dose is inevitably delivered to the irradiated site due to the finite reaction times of the beam delivery system, and it causes a severe distortion of the dose distribution in the target region. Since the amount of the extra dose is proportional to the beam intensity, the dose uniformity deteriorates as the beam intensity is increased in order to shorten the treatment time. In order to overcome this problem and shorten the treatment time, we have developed an optimization method in which the extra dose is integrated into the optimization process of the best weighting matrix. The effectiveness and applicability of the optimization method for spot and raster scanning irradiation were confirmed with computer simulations and also confirmed using irradiation experiments for spot scanning irradiation. The treatment time could be shortened to about one sixth of the time needed without taking the extra dose into account while obtaining the same degree of dose homogeneity in the target volume. A typical treatment time with the proposed method is about 15 s for the irradiation of a spherical target with an 80 mm diameter at 3 GyE.

Download full-text PDF

Source
http://dx.doi.org/10.1118/1.2754058DOI Listing

Publication Analysis

Top Keywords

extra dose
16
treatment time
16
beam intensity
8
shorten treatment
8
optimization method
8
scanning irradiation
8
dose
7
irradiation
6
time
5
optimization
4

Similar Publications

Patients who develop Ewing sarcoma with extra-pulmonary metastasis have a poor prognosis. A recent French protocol, CombinaiR3, was set up to evaluate the efficacy of induction chemotherapy followed by high-dose chemotherapy and metronomic maintenance treatment. It is now closed for inclusions and while waiting for the results, we propose a French consensus guideline for the management of patients diagnosed with Ewing sarcoma with extra-pulmonary dissemination.

View Article and Find Full Text PDF

Unlabelled: HIV cure strategies that aim to induce viral reactivation for immune clearance leverage latency reversal agents to modulate host pathways which directly or indirectly facilitate viral reactivation. Inhibition of bromo and extra-terminal domain (BET) family member BRD4 reverses HIV latency, but enthusiasm for the use of BET inhibitors in HIV cure studies is tempered by concerns over inhibition of other BET family members and dose-limiting toxicities in oncology trials. Here, we evaluated the potential for bivalent chemical degraders targeted to the BET family as alternative latency reversal agents.

View Article and Find Full Text PDF

Pituitary dysfunction after cranial radiotherapy for brain tumor.

Ann Endocrinol (Paris)

March 2025

Fédération d'Endocrinologie, Centre de Référence des Maladies Rares Hypophysaires (HYPO) Hôpital Louis Pradel, Groupement Hospitalier Est, Hospices Civils de Lyon, 59 Boulevard Pinel, Bron, France; Université Claude Bernard, Lyon 1, Lyon, France.

Background: Cranial radiotherapy for extrapituitary brain tumor is a rare cause of acquired pituitary deficiency. The main objective of the present study was to evaluate the incidence and time onset of pituitary deficit and to investigate predictive factors.

Material And Methods: This retrospective cohort study included 246 patients referred to our endocrinology department between 2005 and 2021 for hormone testing after radiotherapy for extra-pituitary brain tumor.

View Article and Find Full Text PDF

SOHO State of the Art Updates and Next Questions: Treatment Options for Marginal Zone Lymphoma.

Clin Lymphoma Myeloma Leuk

February 2025

Clinic of Hematology, EOC, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland; Institute of Oncology Research, Bellinzona, Switzerland; Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland. Electronic address:

Current classifications identify 3 primary types of marginal zone lymphoma (MZL): extra nodal, splenic, and nodal MZL. MZLs typically have excellent long-term outcomes and often do not require immediate treatment. For asymptomatic patients, active surveillance (watch-and-wait) is the standard approach.

View Article and Find Full Text PDF

Evaluating the need for magnesium administration following cardioplegic arrest with del Nido cardioplegia solution.

J Extra Corpor Technol

March 2025

Department of Cardiovascular Perfusion, Cincinnati Children's Hospital Medical Center and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.

Background: del Nido cardioplegia (dNC) solution is widely used in pediatric and congenital cardiac surgery. In 2014, Cincinnati Children's Hospital Medical Center (CCHMC) changed from Mee cardioplegic solution to dNC. Since Mee solution does not contain magnesium, magnesium was administrated post cross-clamp removal, at a dose of 25 mg/kg up to 1 g, to abate hypomagnesemia.

View Article and Find Full Text PDF

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!