basics in radiation oncology slides are in short please do refer radiation reference books, Eg Parez

1. BASICS IN RADIATION
ONCOLOGY

2. RADIATION ONCOLOGY
• Radiation oncology is that discipline of human
medicine concerned with the generation,
conservation, and dissemination of knowledge
concerning the causes, prevention, and
treatment of cancer and other diseases
involving special expertise in the therapeutic
application of ionizing radiation.

3. • Medical Oncology is that discipline of human
medicine specializes in diagnosing and treating
cancer using chemotherapy, hormonal therapy,
biological therapy, and targeted therapy.
• Surgical Oncology branch of surgery applied
to oncology; it focuses on surgical
management of tumours mainly cancerous
tumour.

4. RADIATION THERAPY
• Radiation therapy is the clinical modality dealing
with the use of ionizing radiations in the treatment of
patients’ with malignant neoplasias (and occasionally
benign diseases).
• The aim of radiation therapy is to deliver precisely
measured dose of radiation to a defined tumour
volume with as minimal damage as possible to the
healthy surrounding tissue, resulting in eradication of
the tumour, high quality of survival and prolongation
of survival at competitive cost.

5. CELL CYCLE

6. • G0 – Cell rests and does normal work in the
body
• G1 – RNA and proteins are made for dividing
• S – Synthesis ( DNA is made for new cell )
• G2 – Apparatus for mitosis is built
• M – Mitosis ( The cell divides into 2 cells )

7. • Radiation kills cells that are actively dividing.
• It also causes damage to the surrounding
tissue.
• Radiation doesn’t kill cells instantly, it may
take day to weeks depending on the cell
• Skin, bone marrow, lining of intestines affects
quickly.
• Nerve, breast, brain, and bone tissue show
affects later

8. TYPE OF RADIATION
• IONIZING
– PHOTON THERAPY ( X- RAYS AND GAMMA
RAYS )
– PARTICLE THERAPY ( ELECTRONS,
PROTONS, NEUTRONS, CARBON IONS,
ALPHA PARTICLES AND BETA PARTICLES )
• NON – IONIZING
– RADIO WAVES, MICROWAVES, VISIBLE
LIGHT

9. • RADIOCURABILITY – It refers to the
eradication of tumour at the primary or
regional site and reflects a direct effect of the
irradiation ; but this does not equate with
patients cure from cancer.
• RADIOSENSITIVITY – is the measure of
tumour radiation response, thus describing the
degree and speed of regression during and
immediately after radiotherapy

10. Factors affecting Radiosensitivity
• Histologic type
– High sensitivity: Malignant lymphoma, Seminoma, etc.
– Moderate sensitivity: Epithelial tumour (Carcinoma)
– Low sensitivity: Osteosarcoma, Malignant melanoma, etc.
• Oxygen concentration in tumour tissue:
Radiosensitivity is low in the hypoxic state.
• Cell cycle: Radiosensitivity is high in M phase and
low in S phase.
• Cancer-related genes: p53, Bel-2, Fas, VEGF, etc.

11. 4 R’s of Radiotherapy
• Repair (few hours)
– Lethal damage
– Sublethal damage
– Potentially lethal damage
• Reassortment (few hours)
• Repopulation (5 – 7 weeks)
• Reoxygenation (hours to few days)

12. RADIOTHERAPY
• PRIMARY
• ADJUVANT
• NEO-ADJUVANT
• CONCURRENT
• PALLIATIVE

13. Planning and conduct of course of
Radiation Therapy
• Indication for radiotherapy
• Goal of radiation therapy
• Planned treatment volume
• Planned treatment technique
• Planned treatment dose

14. EXTERNAL BEAM RADIATION
• 2D RADIOTHERAPY
• 3D CONFORMAL RADIOTHERAPY
• INTENSITY MODULATED RADIOTHERAPY
• IMAGE GUIDED RADIOTHERAPY
• STEREOTACTIC RADIOTHERAPY / SURGERY
• INTRAOPERATIVE RADIOTHERAPY
• ELECTROMAGNETIC GUIDED RADIATION THERAPY

16. BRACHYTHERAPY
• CESIUM, GOLD, IODINE, IRIDIUM,
PALLADIUM
• MAIN TYPES OF INTERNAL RADIATION
– INTERSTITIAL
• PERMANENT BRACHYTHERAPY
• TEMPORARY BRACHYTHERAPY
– HIGH DOSE RATE BRACHYTHERAPY
– LOW DOSE RATE BRACHYTHERAPY
– INTRACAVITARY
– INTRALUMINAL
– SURFACE

17. • Radiation Oncologist - Plans treatment.
• Radiation Physicist – Working of radiation
equipment & delivering the radiation dose.
• Dosimetrist – Helps the doctor plan and calculate
the needed number of treatment.
• Radiation therapist – operates the equipment.
• Radiation therapy nurse – cares the patient and
advice them on radiation treatment & dealing with
radiation side efftects.

18. PLANNING
• IMMOBILIZATION
• CT Simulation
• Treatment Planning System
– Target delineation
– Dose prescription
– Beam placement
– Dose calculation
– Plan evaluation & Approval
– Quality assurance
• RADIATION DELIVERY

19. IMMOBILIZATION
• GOALS
• DEVICES
– PLASTIC HEADHOLDERS AND SPONGES
– THERMOPLASTS
– PLASTER OF PARIS
– VACUM MOULDED THERMOPLASTS
– POLYURETHANE FOAMS

20. THERMOPLAST
IMMOBILIZATION

22. Video

24. • TARGET DELINEATION & DOSE
PRESCRIPTION
– Gross tumour volume – 60 – 70 Grays
– Clinical target volume
• High risk – 45 – 54 Grays
• Low risk – 45 Grays
– Planning target volume.

25. COMBINATION THERAPY
• CONCURRENT CHEMOTHERAPY
– CISPLATIN
• 40mg/m² in 1pint NS IV over 20mins ( Cover bottle with
black paper) after premedication
• CARBOPLATIN , TAXOL
• MONOCLONAL ANTIBODIES
– BioMap

26. TARGETED THERAPY
• Targeted therapy blocks the growth and spread of
cancer by preventing cancer cells from dividing or
destroying them directly.
• EGFR monoclonal antibodies
– cetuximab, panitumumab, zalutumumab, nimotuzumab
• EGFR tyrosine kinase inhibitors
– gefitinib, erlotinib, lapatinib, afatanib, dacomitinib
• Vascular endothelial growth factor receptor (VEGFR)
inhibitors
– bevacizumab, sorafenib, sunitinib, vandetanib

27. SIDE EFFECTS

28. ORAL MUCOSITIS

29. • Symptoms include pain, Dysphagia,
Odynophagia, Nausea, Vomiting, Diarrhoea –
GI Toxicity.
• Prevention
– Midline mucosa sparing blocks
– 3D treatment planning and conformational dose
delivery
– Topical benzydamine – anti inflammatory,
analgesic and anti microbial effect

30. • Treatment
– Lidocaine, milk of magnesia, chlorhexidine and
diphendhydramine
– Antibiotic lozenges or sucralfate

31. DERMATITIS

32. • Erythema, desquamation, oedema, necrosis or ulceration
(dose and duration )
• Sweat glands and hair follicles – damaged
• Alopecia permanent – Follicular fibrosis.
• Treatment
– Gentle cleansing with mild agent, washing with water.
– Petrolatum based, castor oil, trolamine.
– Steroids ameliorate the symptoms, but do not prevent.
– Ulcers – Gention violet, Hydrogel dressings
• If infected – Ionic silver powder, topical antibiotics
• Recent years – Topical granulocyte-macrophage-colony
stimulating factor, tacrolimus, platemet derived growth
factor

33. • Chronic skin changes
– Oral pentoxifylline (800mg/day)
– Vitamin E (1000IU/day)
• For 6 months
– Prophylactic use of Pentoxifylline reduces late skin
changes, fibrosis and soft tissue necrosis

34. XEROSTOMIA
• Subjective experience of dry mouth.
• 50 – 60% decrease – 1st week
• Continues in dose dependent fraction
• Symptoms
– Systemic problems – loss of apetite, chronic
oesophagitis, gastroesophageal reflux
– Local problems include dental caries, periodeontal
disease, atrophy and ulceration

35. • Prevention
– Surgical transplantaion of salivary gland.
• Submandibular gland to submental space.
– Intensity modulated RT.
– Amifostine therapy.
• 200mg/m² 15 – 20mins prior irradiation
• Treatment
– Dietary and oral hygiene
– Saliva substitution
– Medications ( carboxymethylcellulose, porcine, bovine
mucin)
– Increase flow – Chewing gums, Lozenges, Vitamin C
– Oral pilocarpine
• 5 -10mg TID

36. SPINAL CORD
• Transient myelopathy ( 2 – 4 months later ).
• LHERMITTE SIGN or LHERMITTE
SYNDROME.
• Rarely, Permanent paralysis, presumed to be
from acute infarction of cord.
HEARING
• Cochlear damage – SNHL ( ˃60grays ).
• Concurrent Chemotherapy with Cisplatin
increases risk.

37. THANKYOU