1. How can I reduce thermoplastic shrinkage?
To minimize shrinkage, it is most important to allow the Klarity® to completely cool before removing from the patient. Moist towels can help speed the cooling. Also be sure that water temperature is maintained at 165° to 170° F. (73° - 77° C.). With thicker thermoplastic, adequate cooling can take up to 20 minutes.
2. What is the best water temperature for heating Klarity®.
Water temperature should be maintained at 165° to 170° F. (73° - 77° C.). Lower temperatures can cause uneven molding and inadequate working time. Higher temperatures can cause excess tackiness, excess stretch and difficult handling.
3. How long should I heat Klarity® in the water bath?
Total heating time varies (1-4 minutes) according to the thickness of the mask, ambient room temperature and the perforation pattern. Be sure that the mask is thoroughly heated at the recommended temperature before removing from the hot water bath. When Klarity® becomes transparent in the water, do not remove immediately. Allow another 30 seconds to a minute to insure complete and even heating. Reinforced masks require longer heating time (3-4 minutes). Be sure that reinforcing strips are heated to complete transparency.
4. What is the purpose of the reinforced perforation patterns?
Klarity® SecureFrames™ and reinforced frames are designed for the highest stability requirements of IMRT. Reinforcing strips hold firmly while the more open perforation areas allow for comfortable breathing and patient visibility.
5. What if the masks are too tight?
Shims can be used if necessary to relieve excessive shrinkage. However, with Klarity® thermoplastic shims are usually not needed, as long as the following steps are taken:
1. Use proper water temperature (165° to 170° F.)
2. Allow mask to cool completely before removing from patient.
3. Mold gently and somewhat loosely around the face, to allow for the minimal shrinkage that will occur.
6. How long should the mask cool before removing it from the patient?
Wait several minutes after the mask turns completely white, at least 15-20 minutes total time.
7. How do I choose the right thickness of Klarity®?
Thicker (3.2mm) Klarity® will provide the highest stability. For this reason Klarity® SecureFrames™ are all 3.2mm thick. However, thinner Klarity® can have less attenuation and may be preferred for more docile patients and lower-energy applications.
8. Will Klarity® masks cause any skin reaction?
Klarity® thermoplastic contains no latex and is not known to cause any allergic or skin sensitive reactions.
9. Can Klarity® frames be used more than once?
Klarity® has memory. If reheated, it will return to its original flat shape. It can then be reheated and formed again. However, multiple uses are not recommended. Klarity® is not easily disinfected, and body fluids can be unwittingly transferred between patients. Multiple heatings will also weaken the Klarity® and may cause instability.
