Source loading Flashcards
–Applicator is pre-loaded and contains radioactive sources at time of placement into the patient.
Hot loading
–Applicator is placed first into the patient and the radioactive sources are loaded later
Afterloading
Generally, the radiation sources are manually afterloaded into applicators or catheters that have been placed within the target volume.
Manual Afterloading
At the end of treatment the sources are removed, again manually.
Manual Afterloading
Manual loading and removal of sources from the applicators or catheters result in some ____
radiation exposure to the medical and support staff
Allows loading of radioactive sources after the source containers (applicators or catheters) are put in place in the patient and have been checked out radiographically for proper positioning using radiopaque markers or source dummies.
Remote Afterloading
are now available that eliminate the direct handling of the radioactive sources. In addition, the sources can be instantly loaded and unloaded, making it possible to provide patient care with the sources retracted into their shielded position.
Remotely controlled afterloading devices
are available for either low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy and for interstitial or intracavitary treatments.
Remote afterloaders
it is possible to use the same type of applicators (e.g., Fletcher-Suit) and dose rates as used in conventional brachytherapy.
LDR units
are performed in a fully shielded room with safety requirements comparable with those required for a cobalt teletherapy unit.
HDR remote afterloader treatments
____ is the most commonly used radioisotope in remote afterloaders, although _____ sources also are used in some units.
192Ir, 137Cs or 60Co
The most common method of source transfer is the ____ to which the source is welded. The cable is moved by a ___
steel drive cable, stepping motor
sources can be retracted into shielded position to allow better patient care under normal as well as emergency conditions.
LDR remote afterloading
permits treatment on an outpatient basis, using multiple fraction regimens.
HDR remote afterloading
is suited for treating large patient populations that would otherwise require prolonged hospitalization if treated by LDR brachytherapy.
HDR remote afterloading
Low dose rate (LDR)
0.4 - 2 Gy/h
Medium dose rate (MDR)
2 - 12 Gy/h
High dose rate (HDR)
> 12 Gy/h
“Dose pulses” of the order of 30 minutes separated by 1 to several hours (Simulation of LDR)
Pulse Dose Rate
