Proccess of Radiotherapy and immobalization.pptx

Radiotherapy work flow

1. Radiotherapy technology I Radiotherapy process& Immobilization Dr. J. M. Eltabib Radiation Oncology Tripoli Medical Center M.R.C.P medicine UK, L.B.M. S Radiotherapy

2. Radiotherapy process& Immobilization Objectives: Workflow of radiotherapy delivery. Importance to immobilize and reproduce daily setup of the patients. Classification of immobilization device. Breast board immobilization device& it’s function. Different steps to be taken while using breast board.

3. Radiotherapy process& Immobilization

4. Radiotherapy process& Immobilization Radiotherapy treatment process: Diagnosis& managment = RO Patient immobilization ( Immobilization devices ) = RTT& RO Imaging( CT, MRI,PET-CT ) = RTT& RO Target delineation = RO Treatment plan system = MP& RO Record and verifying system = RTT& RO Treatment delivery = RTT& RO (RO = Radiation Oncologist, RTT = Radiation Therapist, MP = Medical Physicist)

5. Radiotherapy process& Immobilization Diagnosis& management: Physician will take the clinical history from the patient and do relevant clinical examination. Review all clinical documentations and ask for deficit if needed. Goal is to determine type of cancer& proper staging . Determine aim of radiotherapy (palliative or radical). Discussion of treatment plan with the patient& respond to any queries.

6. Radiotherapy process& Immobilization Diagnosis& management: Determine type of cancer: In most of scenario a tissue biopsy is mandatory (no tissue no issue). Types of biopsy: FNAC, incisional biopsy (TCB& CNB), excisional biopsy. In rare occasion diagnosis made up on radiological evaluation and no need for tissue biopsy eg. palliative scenario, difficult sites (eg brain stem). Tissue biopsy will be send to histopathology lab to determine type of cancer: macroscopic& microscopic examination, staining& IHC.

7. Radiotherapy process& Immobilization Diagnosis& management: Staging of cancer: based on AJCC 8 th edition TNM T = tumor size (T1, T2, T3, T4) N = lymph node involvement (N1, N2, N3) M = distant metastasis (M0, M1) Based on TNM category, staging of the disease will be either: stage I = very early stage disease = very good prognosis stage II = early stage disease = good prognosis stage III = locally advanced disease = poor prognosis stage IV = metastatic disease = incurable disease (palliative measures)

8. Endometrial Cancer Staging (AJCC 6th Ed., 2002/FIGO 1988)

9. Radiotherapy process& Immobilization Immobilization: Positioning & Immobilization are the most crucial part of RT treatment for accurate delivery of a prescribed radiation dose and sparing surrounding critical tissues, thus enhancing therapeutic ratio. Primary goal : To immobilize the patient during treatment = reduce positioning (random) errors (intra-fraction). To provide a reliable means of reproducing the patient’s position from simulation to treatment, and from one treatment to another = reduce systematic errors (inter-fraction).

10. Radiotherapy process& Immobilization 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.

11. Radiotherapy process& Immobilization Set-up errors: 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

12. Radiotherapy process& Immobilization 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.

13. Radiotherapy process& Immobilization Random errors: 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.

14. Radiotherapy process& Immobilization DESIRABLE CHARACTERISTICS 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 usable on simulator, CT/MRI and other treatment planning imaging system. Surface dose should not be altered. Rigid & holds its shape over time.

15. Radiotherapy process& Immobilization 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. Thermoplastic mesh. Cradle-type devices . Modular systems. Stereotactic Systems. Breath Control Systems. Accessories

16. Introduction to Radiotherapy I PLASTER OF PARIS ( POP ): It is prepared by putting POP strips in warm water then fit into the body site.

17. Radiotherapy process& Immobilization Advantages of POP: 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. Disadvantages of POP: Used once. Difficult to steralize& clean.

18. Radiotherapy process& Immobilization Thermoplastic mesh: The most common immobilization device used in radiotherapy. Available in different sizes and shapes. It is rigid in room temperature.

19. Radiotherapy process& Immobilization Thermoplastic principle:

20. Radiotherapy process& Immobilization Different types of thermoplastic mesh: Acrylic, a polymer called (poly methyl methacrylate = PMMA), is also known by trade names such as Lucite, Perspex. Nylon. PLA – Polylactic acid. Poly carbonate. Polyethylene. Poly vinyl chloride (PVC). Teflon etc.

21. Radiotherapy process& Immobilization

22. Radiotherapy process& Immobilization

23. Radiotherapy process& Immobilization Variouse configurations of thermoblastic mesh: Based on thickness& perforations

24. Radiotherapy process& Immobilization Thermoblast mould preparation: The mask is first heated in a water bath or dry oven. When it heated ( for temperature 60 to 65 degree) the material softens and become malleable. The mask is then formed to the patient’ contours and left on the patient until is has completely cooled (at least 10 minutes = cool fan can be used).

25. Radiotherapy process& Immobilization Klarity Air flow Oven water bath Nasal impression

26. Radiotherapy process& Immobilization Types of immobilization based on site of treatment: Head & neck immobilization. Immobilization in Brain tumors Thorax and Breast immobilization Pelvic and abdominal immobilization. Immobilization for the Body extremities. SBRT solution with AIO Board.

27. Radiotherapy process& Immobilization 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 and umbilicus impression. Pelvic cast :- Umbilicus impression.

28. Radiotherapy process& Immobilization Advantages: Thermoplastic provide great reproducibility in daily treatment. Lightweight. Easy to use. Easy to clean. 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. When old it becomes very soft when activated.

29. Thank you for your attention Any Questions?