The Advantages
of Brachytherapy
Brachytherapy is radiation therapy of cancer. The treatment is performed by placing radioactive sources in or near the tumor. In this way, the tumor is treated from inside the body so it receives the highest possible radiation dose with minimal exposure to the surrounding tissues. Teleradiotherapy, which is achieved by the aid of medical high-energy particles accelerators, is an alternative approach to radiotherapy treatment.
Brachytherapy is radiation therapy of cancer. The treatment is performed by placing radioactive sources in or near the tumor. In this way, the tumor is treated from inside the body so it receives the highest possible radiation dose with minimal exposure to the surrounding tissues. Teleradiotherapy, which is achieved by the aid of medical high-energy particles accelerators, is an alternative approach to radiotherapy treatment.
Remote
afterloading brachytherapy means that the source is accurately positioned at
the tumor by a special mechanical-electronic system through thin tubes or
needles. After the treatment, the source is withdrawn into the shielded
source-container, which is the major part of the brachytherapy system. Brachytherapy can be
performed with short treatment times, high dose rate brachytherapy, or over a
longer period of time, low dose or pulsed dose rate
brachytherapy.
Remote Afterloading Brachytherapy for Precision
Remote
afterloading improves radiation control and provides technical advantages,
such as isodose distribution optimization, that improve patient care. Replacing
manual afterloading with remote afterloading reduces the radiation exposure to
radiation oncologists, physicists, attending physicians, source curators,
nurses, and other allied health personnel.
Remote afterloading is an application of the As Low As Reasonably Achievable
(ALARA) principle in radiation control. Remote afterloading offers less
probability of temporarily misplacing radioactive sources or actually losing
sources, events that do occur with manual afterloading.
High dose rate remote afterloading devices yield dose rates greater than
0.2-Gy/min; doses of several gray generally are delivered in minutes. High dose
rate remote afterloading is particularly appealing to facilities with large
patient populations. If treated by conventional manual brachytherapy instead,
prolonged hospitalizations would be indicated. Treating these patients as
outpatients, using multiple fraction treatment regimens on a remote high dose
rate device, is appealing to the patients. Freestanding radiation therapy
centers that do not provide hospital rooms, find high dose rate units appealing,
as well. A dedicated treatment suite with an overhead x-ray tube and fluoroscopy
can accommodate many patients yearly, as large workloads are possible on a
single unit. There is little radiation exposure to attending medical personnel
and none to adjacent patients.
Applicators can be rigidly secured for the short treatment times common with
high dose rate therapy. Consequently, undesired applicator movement observed
during prolonged hospital stays required with brachytherapy is reduced. In some
instances, the high dose rate remote afterloading sources can be configured more
advantageously, yielding more desirable dose distributions than those achieved
with conventional radioactive sources and manual afterloading. And last but not
the least, the very small diameter of high activity source in high dose rate
remote afterloading system allow treatments of interstitial and intraluminal
sites previously untreated or treated only with difficulty with the conventional
techniques.
The Features of Remote Afterload Brachytherapy Systems
All remote
afterload systems offer four essential features:
• A primary storage safe to contain the sources when not in use.
• A mechanism to move the source from the storage safe to and from the applicator in the patient.
• A system to maintain the source in the applicator for a set time in desired positions and to determine their position.
• A mechanism to return the source to the storage safe at the end of treatment and during power failures or other emergencies.
• A primary storage safe to contain the sources when not in use.
• A mechanism to move the source from the storage safe to and from the applicator in the patient.
• A system to maintain the source in the applicator for a set time in desired positions and to determine their position.
• A mechanism to return the source to the storage safe at the end of treatment and during power failures or other emergencies.
Remote Afterloading Systems Offer Flexibility
Remote afterloading of radioactive sources for brachytherapy is becoming increasingly popular as evidenced by the increased sales of remote afterloading systems. With low, medium, and high dose rate options, these units offer the potential for superior dose distributions and the practical advantages of better radiation protection. However, as with any new technology, these systems generate a host of new concerns that the users must address. Remote afterloading systems present a unique set of radiation control questions, particularly when the units fail to function adequately and the sources stick in the applicators. Also, there are no explicit protocols for source calibration. Often, calibration of these sources yields activities at odds with those provided by the manufacturers. This need for a dosimetry protocol is particularly important for the high-activity 192Ir sources which are exchanged frequently.
Often existing hospital rooms or teletherapy vaults not originally designed for the remote afterloading systems are used to house these units. Certain disadvantages in such uses should be considered.
Remote afterloading of radioactive sources for brachytherapy is becoming increasingly popular as evidenced by the increased sales of remote afterloading systems. With low, medium, and high dose rate options, these units offer the potential for superior dose distributions and the practical advantages of better radiation protection. However, as with any new technology, these systems generate a host of new concerns that the users must address. Remote afterloading systems present a unique set of radiation control questions, particularly when the units fail to function adequately and the sources stick in the applicators. Also, there are no explicit protocols for source calibration. Often, calibration of these sources yields activities at odds with those provided by the manufacturers. This need for a dosimetry protocol is particularly important for the high-activity 192Ir sources which are exchanged frequently.
Often existing hospital rooms or teletherapy vaults not originally designed for the remote afterloading systems are used to house these units. Certain disadvantages in such uses should be considered.
Source: http://www.medwow.com/articles/
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