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qa on brachytherapy

1. BRACHYTHERAPY QUALITY ASSURANCE

2. WHAT IS QA; Quality assurance is essential to ensure that the therapy unit perform according to specifications and that unit is safe to use for both patient and staff.

3. ACCEPTANCE ,COMMISSIONING AND QUALITY CONTROL OF HDR UNIT

4. SAFETY SYSTEM ; Mechanical Electrical interlocks Control console display and function

5. PHYSICAL PARAMETERS; Source positional accuracy Source strength calibration Timer Error Timer linearity Leakage and Contamination tests

6. QA TESTS FREQUENCY; Daily Quarterly /source exchange tests Annual

7. SAFETY SYSTEMS; Mechanical Electrical interlocks Control console display and function

8. MECHANICAL SAFETY SYSTEM Functioning of the sensors like pressure ,optical, torque Coupling between transfer tube and unit

9. Coupling between transfer tube and unit and applicators Mechanical integrity of applicator

10. ELECTRICAL INTERLOCKS; Treatment door Indexer ring & guide tube Applicator & guide tube Emergency STOP button to interrupt treatment source ON & OFF indicator Gamma zone monitors at the entry of room

11. CONTROL CONSOLE DISPLAY AND FUNCTION Treatment ON&OFF switch & indicators Source IN and OUT of safe interlocks Door interlock Retrieval of source and dummy indicators Backup system batteries Date and time indicators Warning indicators

12. SOURCE POSITIONAL ACCURACY Source position can be verified source position indicators and autoradiographs Tolerance <1mm

13. SOURCE STRENGTH VERIFICATION; Source strength verification can be verified using any one of the following methods; In air calibration Well type chamber Solid phantom calibration

14. SOURCE STRENGTH VERIFICATION; For well type chamber calibration factors is provided current mode. For accurate measurements select appropriate range (low, medium ,or high) Measure the indexer length (indexer ring –bottom of well type chamber )

15. SOURCE STRENGTH VERIFICATION; Measured variation should not be more than 5%. The measured activity should be entered in the treatment planning system. Compare treatment time calculation for exchanged source manually.

16. TIMER LINEARITY; Calculate the current (change /time )excluding the transit time of source (interval mode) Measure the change collected at different set time intervals Calculate the time measured (charge /current) Plot graph between measured and set time

17. TIMER LINEARITY;

18. TIME ERROR

19. STANDARD &FLETCHER CT/MR TANDEM- OVOID APPLICATOR Combination of x-ray and autoradiograph of an ovoid and tandem channel of a fletchers CT/MR applicators set, used to check if the first dummy position relates to the source dwell position.

20. LEAKAGE AND CONTAMINATION TEST Removable activity from the source holder such as catheters. Swipe test in the catheters or directly placing catheters in the well type counter Measured activity should not exceed 200Bq

21. MACHINE SURVEY Machine survey should be done during source exchange The areas are surveyed at 5cm and at 1 meter distance from the source safe

22. AREA SURVEY All the walls in HDR room should be surveyed ,survey should be done with maximum activity of the source Maze Control console Conduit Ceiling and behind all the side wall

23. EMERGENCY PROCEDURES The emergency procedure should be explained in detail and displayed in the control console area The emergency numbers should be also mentioned in the display chart Staff should be trained in the emergency procedure.

24. DAILY QA Door interlock Warning lights Audio –video system Emergency equipment Timer accuracy Correct date, time ,decay factors Applicators Backup batteries

25. QUARTELY or SOURCE EXCHANGE TESTS Source calibration Source position accuracy ` Interlocks Emergency buttons Gamma zone monitors Time accuracy /linearity Applicators &and transfer tube conditions

26. ANNUAL TEST Leakage radiation - Radiation levels from machine safe and room survey Contamination tests wipe test Practicing emergency situations

27. VANAKKAM...