IMMOBILIZATION DEVICES

TOTAL PROCESS OLD ND NEW PROCEDURES ND TYPES OF IMD

1. IMMOBILIZATION DEVICES P SHIVARAM REDDY INTERN MEDICAL PHYSICIST ( 2019-2020 ) OMEGA HOSPITAL MLA COLONY BANJARA HILLS

2. Framework of presentation Immobilization History of immobilization methods Desirable characteristics of immobilization Materials used for immobilization Types of immobilization Conclusion

3. Radiotherapy treatment process Diagnosis Patient immobilization ( Immobilization devices ) Imaging( CT, MRI,PET-CT ) Target delineation Treatment plan system Record and verifying system Treatment delivery

4. IMMOBILIZATION Positioning & Immobilization are most crucial parts of RT treatment for accurate delivery of a prescribed radiation dose and sparing surrounding critical tissues Primary goal : Reproducibility of position Reduce positioning errors Other benefits : Can reduce time for daily set up Make patient feel more secure & less apprehensive Help to stabilize relationship between external skin marks & internal structures Without proper immobilization ,the patient is at risk for improper treatment and unwanted side effects Immobilization such as moulds casts ,headrests and other devices are constructed to reduce setup errors and patient movement during the treatment.

5. SET-UP ERROR It is used to describe the discrepancy between intended and actual Treatment position. Normally calculated as a shift in treatment field position when a treatment image is compared against it corresponding reference . It may be determined relative to the isocentre, the field borders or both . It comprises a systematic and random error

6. SYSTEMATIC ERROR Systematic component of any error is a deviation that occurs in the same direction and similar magnitude for each total treatment course . Systematic errors may be introduced into patient treatment at the localization, planning or treatment delivery phases. For this reasons these type of errors are referred to as treatment preparation errors. Once frozen into the process, systematic error will occurs in each treatment fraction EXAMPLES Patient movement during CT Interobserver variability in contouring Jaws / MLCs in wrong position Planning and treating the wrong site

7. RANDOM ERROR The random component of any error is a deviation that can vary in direction and magnitude for each delivered treatment fraction. Random error occurs at the treatment delivery stage for this reason are often referred to as treatment or daily execution errors. EXAMPLES Daily variable movements – internal and external. Miss interpreting setup instructions. Poorly immobilized patients.

8. TO REDUCE TREATMENT ERRORS In the console the technologist should set the machine and patient as per the plan by the help of reference image with MV / KV image If there is any machine setup error or patient set up error occurs that should be with in the tolerance limit otherwise investigating and solve the problem before treatment delivery To reduce the machine errors the quality assurance of the machine should be verified by the medical physicist as per QA protocal

9. DESIRABLE CHARACTERITICS OF IMMOBILIZATION DEVICES. Should be transparent to allow visibility of beam light and optical distance indicator Should be light weight, strong and durable Ease to use Ease of making the device Comfort for the patient Minimal place requirement for the storage Resistance of bending and stretching Minimal perturbation of the beam so as not to produce any artifacts in the image acquisitions. Device be useable on simulator, CT/MRI and other treatment planning imaging system Surface dose should not be altered Rigid & holds its shape over time .

10. HISTORY OF IMMOBILIZATION METHODS Early days Standardized neck roll casts Marking tapes ( Skin markers ) Breath hold technique

11. 1960-70s POP ( CaSO4.1/2H20 ) Skin markers Bite blocks Card board,Icecream sticks,syringe

12. Polyurethane foam

13. EARLY 1980 AND ONWARDS L asers AIO Base plate I ndexer Head rests Plexiglass T hermoplastic mould

14. MATERIALS USED FOR IMMOBILIZATION Variety of materials and methods are available for immobilization. Selection of the immobilization depends on the comfort of the patient and preferred by the Radiation Oncologist. Plaster of Paris. Thermoplastics. Vac- lok Bite blocks.

15. PLASTER OF PARIS ( POP ) It is prepared by heating GYPSUM to a temperature of 373K. when gypsum is heated to a temperature of 373K, it loses three-fourths of its water of crystallization and forms Plaster of paris Advantages of Plaster of Paris 373k It is easily available >>>>>>> comfortable easy to mould strong and light easy to remove permeable to radiography permeable to air and hence underlying skin can breathe. non inflammable

16. PLASTIC MATERIALS   Plastic is subset of polymers • Thermoplastic • Thermosets • Thermoplastic elastomers • Polymer composites

17. DIFFERENT THERMOPLASTICS Acrylic, a polymer called poly(methyl methacrylate) (PMMA), is also known by trade names such as Lucite, Perspex. Nylon PLA – Polylactic acid Polycarbonate Polyethylene Poly vinyl chloride ( PVC ) Teflon etc.

18. THEMOPLASTICS It Consists of simple molecular structure All macro or monomers are chemical independent Intermolecular forces keeps them together

19. THERMOPLASTIC PRINCIPLE

20. VARIOUS CONFIGURATIONS OF THERMOPLASTIC

21. THERMOPLASTIC MOULD PREPARATION The most common immobilization device used to treat cancers is Thermoplastic. Available in different sizes and shapes . It is rigid in room temperature. When it heated in water( for temperature 60 to 65 degree)the material softens and become malleable) The mask is first heated in a water bath. then the warm, pliable mask is pulled over the patient The mask is then formed to the patient’s contours and left on the patient until is has completely cooled P MMA (Poly methyl methacrylate)

22. ADVANTAGES Thermoplastic provide great reproducibility in daily treatment lightweight and easy to use. Additionally modification can be made to mask if the patient experienced with swelling or weight loss during the course of treatment. DISADVANTAGES Windows cut can not be reused and when old it becomes very soft when activated .

23. WHY WE ARE USING THERMOPLASTICS ?

24.   IMPRESSIONS : Head cast :- Ear impression & Nasal impression Head & neck cast :- Ear impression, and sternal notch impression Chest cast :- Sternal notch impression Abdomen cast :- Sternal notch, umbilicus impression Pelvic cast :- Umbilicus impression

25. VAC-LOK Radiolucent plastic cushions filled with tiny polystyrene ball Semi-deflated cushion moulded around the patient's gross body contours Using vacuum pump air is pumped out and the balls come together to form a firm solid support The cushion becomes an entirely rigid and comfortable mould of the patient's body

26. VAC-LOK

27. The direct beam of radiation will pass through such mouth guard material, but will create a space between the restoration and the cheek or tongue. ... Mouth guards can also be created to prevent biting of irradiated tissues that might become swollen during treatment Patient supine with a straight spine Custom made mouth bite ice cream sticks, card board etc. Pushing the tongue inferiorly when irradiating the hard palate or upper alveolus Separate the roof of the mouth from the inferior oral cavity when irradiating the tongue MOUTH BITE

28. OTHER ACCESSORIES WE ARE USE IN MOULD ROOM HEAD RESTS INDEXING BAR KNEE REST & FOOT REST

29. SHOULDER RETRACTOR

30. TYPES OF IMMOBILIZATION  Head & neck immobilization Immobilization in Brain tumour Thorax and Breast immobilization Pelvic and abdominal immobilization I mmobilization for the Body extremities SBRT solution with AIO Board

31. HEAD & NECK IMMOBILIZATION Head & neck immobilization Initial construction and selection of proper immobilization for H&N cancer is one of the most important parts of confirming proper treatment of the patient . Current methods for the H&N tumours include a variety of masks moulds, and frame systems. In some instances, shoulder Retractors are used to pull the shoulders out of the treatment field for the neck.

32. IMMOBILIZATION IN BRAIN For the General brain tumour and whole brain cases the mostly common immobilization device is the 3 clamp & Uniframe ,Thermoplastic Immobilization becomes more complex for radiosurgery, Cyber knife and Gamma Knife procedure because the requirements for positional and numerical accuracy for the dose delivery are -+1mm .

33. THORAX AND BREAST IMMOBILIZATION There are 3 common immobilization Devices used when treating the tumours in the chest cavity, VACLOK BREAST BOARD 2 CALMP OR 4 CLAMP THORACIKC MOULD .

34. BREAST BOARD

35. PELVIC IMMOBILIZATION There are two important aspects to be followed in the case of Pelvic Immobilization Properly maintain patients outer contour during treatment with respect to the isocenter Immobilization system such as vac lok ,belly board, and thermoplastic masks are commonly used during treatment of pelvic region .

36. IMMOBILIZATION FOR EXTREMITIES Immobilization for the body Extremities is a quite challenge for us But with this special thermoplastic solution we can perform it easily. The system consists of a low density carbon fiber base plate with a leg support, two comfort cushions and dedicated masks . The base plate can be indexed to any couch top on 2-pin bars and has multiple holes to offer a maximum of possibilities for positioning and immobilizing both upper and lower extremities .

37. SRS / SRT Stereotactic radiosurgery (SRS) is a non-surgical radiation therapy used to treat functional abnormalities and small tumours of the brain. It can deliver precisely-targeted radiation in fewer high-dose treatments than external therapy, which can help preserve healthy tissue. Stereotactic radiosurgery (SRS) and Stereotactic radiotherapy (SRT) use precisely focused radiation beams to treat tumours and other abnormal growths in the brain, spinal column and other body sites.

38. SBRT IMMOBILIZATION: Stereotactic Body Radiation Therapy (SBRT) – SBRT is a treatment procedure similar to SRS, except that it deals extra-cranial radiosurgery Simple to use, highly indexable, and easily adjustable. The carbon fiber baseplate is lightweight and has handgrip holes on either side for easier placement and hanging options. The SBRT Baseplate indexes to the couch top in two places, and scalloped edges allow the belly and knee bridge to be fixed in the best position for the patient. The height of the belly and knee bridges can be adjusted quickly, and the bridges lock and unlock without fuss. The SBRT System is also equipped with an ergonomic belly compression paddle designed to maximize patient comfort while providing necessary immobilization .

39. SBRT

40. Belly Bridge The Belly Bridge and is equipped with compression paddle for supressing the abdominal regional.  The bridge is easy to lock and unlock on the SBRT Baseplate and the bridge height is easily adjustable .  Additionally, the compression paddle can be adjusted laterally and offers varying levels of compression for better customization and indexing.  The SBRT System can be used with or without the belly compression bridge and paddle .

41. RESPIRATORY BELT Provides pneumatic compression and immobilization to the abdominal region . The respiratory belt can be used for customized, comfortable belly suppression. it is secured with Velcro and comes with an easily readable pressure gauge.  The SBRT System can be used with or without the respiratory belt.

42. BLUE BAGS Blue bags are stronger, more reliable A durable and non-permeable nylon shell prevents punctures and tears. All bags are completely air-tight and leak-proof, filled with low density polystyrene mini-spheres. Metal-free valves are fully MR Safe. A corner grommet allows for easy storage. blue bags are designed for long-term multi-patient use. The nylon shell can be easily cleaned between patient use. The durable design means that bags need to be replaced less often. blue bags come with replaceable valves and can be equipped with valves to fit all standard vacuum pumps.