3. We see what we want?
Common things are usually very rare to spot.
4. History
A 23 year old female was referred by
plastic surgeons for radiotherapy to the
posterior ear lobe, following the
development of a Keloid Scar, three
years after an ear piercing
No family history of keloids
5. Pathology
Keloid is a unique human dermal
fibroproliferative disorder that occurs after injury,
inflammation, surgery,and burn.
Commonly causes of keloids include acne,
folliculitis, chicken pox, vaccinations and trauma
(such as, earlobe piercing, lacerations, or surgical
wounds).
It is a benign growth, well-demarcated area of
fibrous tissue overgrowth that extends beyond the
original defect
17. Diminishes size and induration (HTS >Keloid) when
used as monotherapy
<10% Recurrence when combined with surgery
Photos Courtesy of Dr. Redett
Pressure Therapy
19. Orthovoltage machine
Produces low energies
Deposits 100% of the dose at 0.5 cm of skin surface.
Effective in treating skin lesions like keloids.
Radiation beam is directed by a cone to the site of
excision.
Beam is Filtered and collimated by copper and lead
shields- peak kilovoltage.
21. TREATMENT PROCESS
Cell cycle versus cell death
The cell proliferation cycle is defined by two time
periods: Mitosis M, where division takes place.
The period of DNA synthesis S.
The S and M portions of the cell cycle are separated
by two periods (gaps) G1 and G2.
The time between successive divisions (mitoses)
is called the cell cycle time.
The cell cycle time for mammalian cells is of the
order of 10 - 20 hours:
22. Treatment process cont….
S phase is usually in the range of 6 - 8 hours.
M phase is less than 1 hour.
G2 is in the range of 2 - 4 hours.
G1 is in the range of 1 - 8 hours.
In general, cells are most radio-sensitive in the M and
G2 phases, and most radio-resistant in the late S
phase.
SXRT has to be delivered within 48 hours for
maximum effect.
23. Fate of irradiated cells
Irradiation of a cell will result in one of the following nine
possible outcomes:
No effect
Division delay: The cell is delayed from going
through division.
Apoptosis: The cell dies before it can divide or
afterwards by fragmentation into smaller bodies,
which are taken up by neighboring cells.
Reproductive failure: The cell dies when
attempting the first or subsequent mitosis.
Genomic instability: There is a delayed form of
reproductive failure as a result of induced
genomic instability.
24. CONT..
Mutation: The cell survives but contains a
mutation.
Transformation: The cell survives but the
mutation leads to a transformed phenotype and
possibly carcinogenesis.
Bystander effects: An irradiated cell can send
signals to neighboring unirradiated cells and
induce genetic damage in them.
Adaptive responses: The irradiated cell is
stimulated to react and become more resistant to
subsequent irradiation.
25. RADIATION SAFETY
Three principles of radiation protection:-
TIME, SHIELDING, DISTANCE.
Risk of carcinogenesis attributable to
keloid radiation therapy is very low when
surrounding tissues, including the thyroid
and mammary glands, especially in
children and infants, are adequately
protected
27. 1. If the technology is safe, then we will be safe.
2. If the human is safe, then we will be safe
3. If the organization is safe, then we will be safe’.
28. Patient tolerability
Studies indicate that post
excision SXRT is well
tolerated by patients
Non-invasive
Single day treatment
unless otherwise stated
The Other big question ?
After treatment is it acceptable ?- Aesthetically
29. Patient Distribution at NRC
Female Male
Ear 238 48
Abdomen 13 8
Face 9 40
others 100
360
114
210
30. In this case…
Plastic surgery was carried out to remove the Keloid
Scar. The patient attended the following day for a
single dose of radiotherapy to the scar, plus a small
margin of 5mm. The pinna was taped forward to
expose the effected posterior section of the lobe.
31. Radiotherapy prescription
12Gy in single fraction.
HVL 0.2mm Cu
Energy used was:- 100kv.
Actual Field size:- 3.5 x 1.5 cm –margins of
2mm
Cone size used:- 4 X 6cm
Shielding :-A lead cut out was used to
define the field size and protect the
surrounding
tissue.