 |
 |
 |
 |
 |
Frequently Asked Questions |
|
 |
1. Which nuclides can the surgical gamma probe detect? The hand probe CXS-OP-SZB is sensitive for all nuclides with energies between 70 keV and 511 keV. The standard collimator sleeve however has an optimized lateral shielding only with the use of 99mTc (<0,1% at 140 keV). 2. Why is it necessary to set the nuclide on the control panel? The aim of the gamma guided surgery is to localize nuclide enrichments (e.g. in sentinel lymph nodes) as exactly as possible. For that purpose the ratio of its signal to background signal should be as high as possible. For the background radiation consists also of γ-quants with less energy this low energy part of the spectrum can be suppressed by setting an energy threshold right below the photo-peak of the used nuclide. The 6-fold switch changes this threshold in steps according to the data given in the manual (par. "Technical Data"). 3. Which switch position has to be used for a specific nuclide? The switch positions are named by nuclides that are representative for a group of nuclides with similar energies. Please read the manual (par. "Technical Data") for details. 4. Which switch position shall be used for the detection of the total γ-spectrum? The switch position 201Tl represents an energy threshold close above the noise of the detector (60 keV). Using this position enables to detect all γ-quants with energies above this threshold, and no suppression of any part of the spectrum is done. In this way one has a higher signal for any nuclide than with a switch position appropriate to the used nuclide. 5. Is it possible to change the energy thresholds by the user? The energy thresholds are implemented by the manufacturer and cannot be changed by the user. However, an additional energy threshold according to the customer’s needs can be installed at position "VI" on request. 6. Why collimation? The tissue parts surrounding the radio labeled lymph node also radiates by the radio pharmaceutics which are not enriched in the sentinel node. Reducing the opening angle of the probe by different collimator sleeves with different shapes enables the suppression of this radiation and improves in this way the signal ratio node-to-background. The detection of the node is easier then, but the search might be more difficult because it may easily happen that simply the target is missed during the scanning of the tissue. The localization as exactly as possible by gamma scintigraphy before the operation is recommended. The Crystal standard probe (CXS-OP-SZB) has a collimation angle of 40º and is to be found most suitable for sentinel lymph node detection procedure (other collimation angles are available). For more flexibility we offer the Flexible Gamma probe (CXS-OPSZF) with changeable collimation angles of 20º, 40º, 60º. 7. How to change the collimation? The collimation can be easily changed by replacing the collimator sleeve/tip by other differently designed collimator sleeves/tips. 8. Is it possible to change the collimation during the surgery? Both the safety of the patient and the safety of the probe are ensured by the polished and sterilizable stainless steel probe sleeve that hide all the functional and non-sterilizable parts of the probe. A change of the collimation is only possible when the frequently used sterile plastic cover can be removed, another collimator sleeve can be screwed on and another sterile plastic cover can be applied again. This can only be done out of the sterile operational area. Because this is somewhat complicated, we therefore suggest to prepare two probes with different collimators. 9. What is the life time of the batteries? The life time of the rechargeable batteries ranges between 4 and 5 years, or for about 200 charging cycles. 10. How can the lifetime of the batteries be extended as much as possible? Please make sure that the batteries always have a charging level as high as possible. It is recommended to recharge the batteries to full capacity immediately after each use and before each storage. The manufacturer of the batteries suggests to keep the batteries connected with the mains voltage, even when the system is not used. Over-charging is not possible! A very deep discharging of the batteries must be avoided because this leads to the destruction of the batteries. 11. What can happen when the "Bat. low" LED is on and the batteries are drained? Due to the insufficiently high voltage the electronics will not work properly and can create fault signals like unexpected erratic counts and permanent sound even when no radiation is present. 12. Is it possible to operate the system with connected charging device? After a long usage period (>10 hours) the batteries will run low. In this event, the operation with the system can be continued with connecting it to the mains voltage by means of the battery charger. For that purpose switch off system, plug in battery charger, connect the charger with the mains voltage, switch system on again (ready to go after 15 seconds initialization of the electronics). 13. Are there any wearing parts? No, there are not. 14. Which probe parts may be sterilized; which methods are allowed? The collimator sleeve of stainless steel with integrated tungsten collimator may be sterilized with the usual methods (plasma sterilization, steam sterilization at 150°C and 4 bar). Generally only the collimator sleeves should be sterilized. The use of several sterilized sleeves is recommended to have the system ready for use even when a collimator sleeve is off for sterilization. The detector head and the "stand pipe" that are normally protected by the probe sleeve are not allowed to be disinfected by any liquids. If disinfection by solvents cannot be avoided (should be the exception!) please note the following instruction: The end of the detector head has to be sealed properly by adhesive tape. The probe must be held with its head downwards. Now a careful disinfection with a wand is possible. However, damage of the probe cannot be excluded, nevertheless. 15. Does the system need to be re-calibrated? The Crystal surgical gamma probe system requires a simple monthly function calibration test. This procedure meets the legal regulations. It can be done on site by the surgeon or surgical technician and is described in the user manual that comes with the system. If a deviation of 25% or more occurs, the system is subject for re-calibration, done by the factory only. If not performing the function calibration test on a regular base, we recommend to have the system checked every 3 years by the manufacturer. 16. Which collimation should I use? This depends on type of the surgery, the specific geometric conditions of the radio labeled tissue, the applied total dose, the time dependent change of the nuclide's distribution, and also on the experience of the surgeon. Generally, it is suggested to work with standard collimator sleeve (40°) in order to get a faster survey of the nuclide distribution. To distinguish between nuclide enrichments closer to each other, a collimator sleeve with a smaller opening angle can be chosen later. 17. What can be measured with the probe? The use of a surgical gamma probe makes sense with the following surgeries. There are some suggestions how the patients should be prepared (according to Dr. rer.nat. D. Lange, PhD, Nuclear Medical Dept., Heidelberg University Germany):
18. Are there any sources of interference? A surgical probe is a very sensitive mechanical and electronic device, i.e. usage and storage should be done accordingly. Very efficient amplifiers and subsequent electronics in the hand piece of the probe allow an efficient conversion of the γ-radiation in electronic signals. The same sensitive electronics however amplify other electro-magnetic radiation coming from sources near the probe, too. In order to avoid fault signals all electro-magnetic sources near the probe should be removed. Please refer to the users manual paragraphs "Installation Location" and "Safety Instructions". 19. How should the system be stored? The system should be packed and stored in the blue hard cover case that comes with the system. In the event you are transporting the system, we recommend to use the white plastic protection sleeve for the surgical probe. The system comes with a surgical probe holder that you can attach to the control unit. 20. Does the system have a certification of the EC? The system CXS-SG03 was developed and manufactured in Germany, taking maximum precision and security aspects into consideration. Each system underlies a single inspection at the Notified Body 0633 (TU Berlin, Prüf- und Zertifizierungsstelle für Medizinprodukte) according to the directive 93/42/EEC, annex IV. Copies of the manufacturer’s final inspection, of the test protocols on the type examination and on the MPK classification acc. to §13 MPG (class IIa), and of the EC Verification Certificate are included with each delivery. Each certified system is labeled with the CE-mark in combination with the identification No. 0633. 21. What is the warranty on the system? The manufacturer warrants that the Gamma Probe Measuring System CXS-SG03 and its parts are free from mechanical defects in regards to material and workmanship for 12 months from the date of delivery. Note: extended warranties are available. |
Surgicalprobe.com is a division of Nuclear Fields USA Corp. |
|