scholarly journals Letter in Response to Doyen et al., “Early Toxicities After High Dose Rate Proton Therapy in Cancer Treatments”

2021 ◽  
Vol 11 ◽  
Author(s):  
Pierre Montay-Gruel ◽  
Marie-Catherine Vozenin ◽  
Charles L. Limoli
Keyword(s):  
Dose Rate ◽  
Proton Therapy ◽  
High Dose Rate ◽  
High Dose ◽  
Cancer Treatments

scholarly journals Early Toxicities After High Dose Rate Proton Therapy in Cancer Treatments

2021 ◽  
Vol 10 ◽  
Author(s):  
Jérôme Doyen ◽  
Marie-Pierre Sunyach ◽  
Fabien Almairac ◽  
Véronique Bourg ◽  
Arash O. Naghavi ◽  
...  
Keyword(s):  
Dose Rate ◽  
Proton Therapy ◽  
Malignant Tumors ◽  
Retrospective Chart Review ◽  
High Dose Rate ◽  
High Dose ◽  
Cancer Treatments ◽  
Conventional Dose ◽  
Grade 3

BackgroundThe conventional dose rate of radiation therapy is 0.01–0.05 Gy per second. According to preclinical studies, an increased dose rate may offer similar anti-tumoral effect while dramatically improving normal tissue protection. This study aims at evaluating the early toxicities for patients irradiated with high dose rate pulsed proton therapy (PT).Materials and MethodsA single institution retrospective chart review was performed for patients treated with high dose rate (10 Gy per second) pulsed proton therapy, from September 2016 to April 2020. This included both benign and malignant tumors with ≥3 months follow-up, evaluated for acute (≤2 months) and subacute (>2 months) toxicity after the completion of PT.ResultsThere were 127 patients identified, with a median follow up of 14.8 months (3–42.9 months). The median age was 55 years (1.6–89). The cohort most commonly consisted of benign disease (55.1%), cranial targets (95.1%), and were treated with surgery prior to PT (56.7%). There was a median total PT dose of 56 Gy (30–74 Gy), dose per fraction of 2 Gy (1–3 Gy), and CTV size of 47.6 ml (5.6–2,106.1 ml). Maximum acute grade ≥2 toxicity were observed in 49 (38.6%) patients, of which 8 (6.3%) experienced grade 3 toxicity. No acute grade 4 or 5 toxicity was observed. Maximum subacute grade 2, 3, and 4 toxicity were discovered in 25 (19.7%), 12 (9.4%), and 1 (0.8%) patient(s), respectively.ConclusionIn this cohort, utilizing high dose rate proton therapy (10 Gy per second) did not result in a major decrease in acute and subacute toxicity. Longer follow-up and comparative studies with conventional dose rate are required to evaluate whether this approach offers a toxicity benefit.

A quantitative FLASH effectiveness model to reveal potentials and pitfalls of high dose rate proton therapy

2022 ◽  
Author(s):  
Miriam Krieger ◽  
Steven Water ◽  
Michael M Folkerts ◽  
Alejandro Mazal ◽  
Silvia Fabiano ◽  
...  
Keyword(s):  
Dose Rate ◽  
Proton Therapy ◽  
High Dose Rate ◽  
High Dose ◽  
Effectiveness Model

“In Vivo” Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments

2008 ◽  
Author(s):  
S. A. González-Azcorra ◽  
A. Mota-García ◽  
M. A. Poitevín-Chacón ◽  
B. J. Santamaría-Torruco ◽  
M. Rodríguez-Ponce ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Dose Rate ◽  
High Dose Rate ◽  
In Vivo Dosimetry ◽  
High Dose ◽  
Cancer Treatments ◽  
High Dose Rate Brachytherapy

scholarly journals A New Technology for Fast Two-Dimensional Detection of Proton Therapy Beams

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Robert Hollebeek ◽  
Mitch Newcomer ◽  
Godwin Mayers ◽  
Brian Delgado ◽  
Gaurav Shukla ◽  
...  
Keyword(s):  
Dose Rate ◽  
Spatial Resolution ◽  
Proton Therapy ◽  
Time Resolution ◽  
High Energy Physics ◽  
High Energy ◽  
High Dose Rate ◽  
High Dose ◽  
High Time Resolution ◽  
High Count

The Micromesh Gaseous Structure, or Micromegas, is a technology developed for high count-rate applications in high-energy physics experiments. Tests using a Micromegas chamber and specially designed amplifiers and readout electronics adapted to the requirements of the proton therapy environment and providing both excellent time and high spatial resolution are presented here. The device was irradiated at the Roberts Proton Therapy Center at the University of Pennsylvania. The system was operated with ionization gains between 10 and 200 and in low and intermediate dose-rate beams, and the digitized signal is found to be reproducible to 0.8%. Spatial resolution is determined to be 1.1 mm (1σ) with a 1 ms time resolution. We resolve the range modulator wheel rotational frequency and the thicknesses of its segments and show that this information can be quickly measured owing to the high time resolution of the system. Systems of this type will be extremely useful in future treatment methods involving beams that change rapidly in time and spatial position. The Micromegas design resolves the high dose rate within a proton Bragg peak, and measurements agree with Geant4 simulations to within 5%.

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