Author Topic: Active surveillance & active researching of future options  (Read 492 times)

KeepSmiling

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Active surveillance & active researching of future options
« on: January 05, 2019, 03:26:22 pm »
As you study your future treatment options you may want to give some consideration to Proton Therapy. To gain basic knowledge about Proton Therapy, please use a search engine such as google and type in the words "Proton Therapy". You may want to study this: https://www.proton-therapy.org. You may also want to
read info found here: https://www.massgeneral.org/radiationoncology/BurrProtonCenter.aspx
"...Irregularly shaped lesions located near critical structures, tumors in children, and large tumors near any critical organ are well suited for proton beam therapy. Protons have a physical advantage over gamma rays and x-rays when it comes to sparing normal tissues. Protons deposit most of their radiation energy in what is known as the Bragg Peak, which occurs at the point of greatest penetration of the protons in tissue. The exact depth to which protons penetrate, and at which the Bragg Peak occurs, is dependent on the energy or modulation of the proton beam. This energy can be very precisely controlled to place the Bragg Peak within a tumor or other tissues that are targeted to receive the radiation dose. Because the protons are absorbed at this point, normal tissues beyond the target receive very little or no radiation. Proton energy can be adjusted to match the depth of the target with a sharp drop in dose beyond the Bragg Peak..."

In the past, some ANA Discussion Forum Members have expressed concerns about proton therapy due to "range uncertainties". Dr. Paganetti, who is one of the authors of the following study, discusses Intensity-modulated proton therapy (IMPT) to address range uncertainties here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651132/
Semin Radiat Oncol. 2018 Apr;28(2):88-96. doi: 10.1016/j.semradonc.2017.11.005.
Robust Proton Treatment Planning: Physical and Biological Optimization.

Unkelbach J1, Paganetti H2.
Author information
1Department of Radiation Oncology, University Hospital Zürich, Zürich, Switzerland. Electronic address: jan.unkelbach@usz.ch.
2Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
Abstract
Accurate prediction of tumor control and toxicities in radiation therapy faces many uncertainties. Besides interpatient variability in the response to radiation, there are also dosimetric uncertainties, that is, differences between the dose displayed in a treatment planning system and the dose actually delivered to the patient. These uncertainties originate from several sources including imperfect knowledge of the patient geometry, approximation in the physics of radiation interaction with tissues, and uncertainties in the biological effectiveness of radiation. Generally, uncertainties are considered in the treatment planning process by applying margins. In intensity-modulated radiotherapy (IMRT), this leads to the planning target volume (PTV) concept. Intensity-modulated proton therapy (IMPT) is widely considered as the future of proton therapy. The treatment planning methods for IMPT and IMRT are similar and based on mathematical optimization techniques for both modalities. However, the PTV concept has fundamental limitations in IMPT. Therefore, researchers have developed robust optimization methods that directly incorporate uncertainties into the IMPT optimization problem. In recent years, vendors of commercial planning systems have started to implement these methods so that robust IMPT planning becomes available in clinical practice. This article summarizes uncertainties in proton therapy and the limitations of the PTV concept to deal with them. Subsequently, robust optimization techniques to overcome these limitations are reviewed.
PMID: 29735195 PMCID: PMC5942229 [Available on 2019-04-01] DOI: 10.1016/j.semradonc.2017.11.005

*Please note that we selected Massachusetts General Hospital Proton Center for treatment in 2013, which resulted in a good outcome. Occasional tinnitus  and Total deafness in AN was/is present before /after proton treatment, however no other issues are present. None. If interested in details about what happened, please read all my posts (Search under "Keep Smiling".) Sending our best wishes to all of you!
12/O6/2O12: 1.5 cm lesion.Proton Therapy-July/Aug, 2013 Massachusetts General Hospital. 2/23/2018 MRI: 1. Small .5 cm x(AP) x .8 cm (TV) x .8 cm (CC )left intracanicular acoustic schwannoma) Completely deaf in one ear. Occasional tinnitus. Zero side effects.

Freelander

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Re: Active surveillance & active researching of future options
« Reply #1 on: January 12, 2019, 01:51:19 pm »
KeepSmiling, It's good to remind the forum about proton therapy (PT).    Although the number of AN patients offered or having PT is less than the more commonly found x-ray therapies, such as gamma knife or cyberknife, due to the fewer number of PT centers, anyone considering radiation for their AN needs to include PT in their research and decision making process.   It is especially beneficial to consult with the PT centers that are highly experienced treating an acoustic neuroma.