diagnosis and treatment of local radiation injuries diagnosis and treatment of local radiation...
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DDIIAGNOSAGNOSIISS AND TREATMENTAND TREATMENT OF OF
LOCAL RADIATION INJURIESLOCAL RADIATION INJURIES
DDIIAGNOSAGNOSIISS AND TREATMENTAND TREATMENT OF OF
LOCAL RADIATION INJURIESLOCAL RADIATION INJURIES
Module XIIIModule XIII
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Significance of local radiation injuries
In over 90% of radiation accidents only local injuries occur mainly due to direct contact with source
Most frequent complicating factor of acute radiation sickness (ARS)
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Common sources inducing radiation injury
192Ir 60Co 137Cs Fission products (beta exposure) 90Sr X-ray machines X-ray fluorescence Cyclotron products
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Typical scenarios leading to partial body radiation injuries
finding lost unshielded sources
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Common features of local radiation injuries
Occurrence of extremely high local radiation doses causing very severe tissue damages (often result of direct contact with sealed source)
Very steep dose gradient in all directions from centre (“inverse square law”)
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Severe radiation injury of hand - Algerian accident with lost 925 GBq (25
Ci) 192Ir source, 1978
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Common features of local radiation injuries
Clinical symptoms may appear relatively late after exposure, or successively from moment of irradiation, following typical clinical course
The earlier the onset of symptoms, the more severe the intensity of exposure
Range of manifestations - erythema, swelling, blisters, ulceration, necrosis and sclerosis.
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Factors determining severity of local radiation injuries
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Penetration of Penetration of rradiationadiation
I I I I I ı0.001 0.01 0.1 1 10 100
Cellnucleus
Celldiameter
100 cell diameter
Auger
5.3 MeV alpha
0.15 MeV beta
1.7 MeV beta
mm
beta
alpha
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Human skin structureHuman skin structure
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Penetration of radiation through skin stuctures
Alpha radiation is absorbed in superficial layers of dead cells within the stratum corneum
Beta radiation damages epithelial basal stratum. High energy ß-radiation may affect vascular layer of derma, with lesion like thermal burnGamma radiation damages underlying tissues and organs
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Clinical course of Clinical course of llocal ocal rradiation adiation iinjuriesnjuries
Response of skin to ionizing radiation - radiation dermatitis or cutaneous radiation syndrome (CRS)
Types of skin responses - depending on dose: 1. Initial erythema2. Dry desquamation 3. Erythema proper4. Moist desquamation5. Ulceration and necrosis6. Late effects: dermal atrophy, hyperpigmentation,
fibrosis
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Blister formation
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On right hand severe blisters developed after irradiation; on left hand epidermis has sloughed. Presence of hyaline fluid gives blisters translucent appearance
Moist desquamation
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Ulceration and necrosis
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Hyperpigmentation
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Section of normal skin (left) and of healed lesion (right) from same bovine hide.
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Diagnosis of local radiation injuries Diagnosis of local radiation injuries in early phasein early phase
Goals:
• Establishment of origin of observed local injuries
•Consider radiation as a possibility!
• Assessment of severity and clinical consequences
Be careful with the early prognosis!
• Early dose estimation
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Stage/symptoms Dose range (Gy)
Time of onset
Erythema Epilation Dry desquamation Moist desquamation Blister formation Ulceration (within skin) Necrosis (deeper penetration)
3-10 > 3 8- 12 15-20 15-25 > 20 25
2-3 weeks 14-18 days 25-30 days 20-28 days 15-25 days 2-3 weeks 3 weeks
Time of onset of clinical signs of Time of onset of clinical signs of skin injury depending on dose of skin injury depending on dose of
radiation exposureradiation exposure
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Differential Differential ddiagnosis iagnosis TThermalhermal vs vs rradiation adiation bburnsurns
Thermal injuryThermal injury prompt pain, severe inflamatory response, death of affected cells and destruction of tissue
All types of cells and tissue components damaged
Radiation injury initially painless, and evidence of cell death is not apparent until epidermal surface layers are shed and local cell renewal systems have failed
Types of cells found in skin vary in their sensitivity to ionizing radiation
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Skin response curves as diagnostic and prognostic means of local radiation injury
0
0,5
1
1,5
2
2,5
3
3,5
4
0 20 40 60 80 100
Days after radiation exposure
Necrosis
Deep ulceration
Superficial ulceration
Blisters
Moist desquam.,bl. appearence
Erythema andoedema
Bright erythema
Slight erythema
Intact skin
Beginning of epithelialization
Re-epithelialization 20 %
or scar formation
Complete epithelializationskin atrophy or dry desq.
y(+) y(-)
2.
1.
50 %
80 %
Complete epithelializationskin atrophy
Intact skin
Han
d (7
0 G
y )
Foot (18 Gy -n)
amputation on day 62
Amputation 4.5 years later
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Diagnosis of lDiagnosis of lateate radiationradiation i inducednduced injuries injuries
GoalsDetermining extent of damage
(especially lesions that become irreversible)
Decision on therapy(conservative/surgical)
Choosing most suitable moment for surgery
Dosimetry
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Contact Contact lliquid iquid ccrystalrystalththermographyermography
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ThermographyThermography
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ThermographyThermography
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Perfusion Perfusion sscintigraphycintigraphy
Phase 1: Blood flow Phase 2: Blood pool
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ThermographyThermography
Normal hand thermography
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Later phase of clinical course:tthermographyhermography
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Determination of Determination of rradiationadiation induced induced ttissue issue ooedemaedema
MR and CT images:
Useful to show early oedema associated with radiation induced inflamatory reaction and deep swelling especially when affecting muscles
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Accident reconstruction
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Principals of treatment Principals of treatment llocal ocal rradiation adiation iinjuriesnjuries – I– I
Standardized therapeutical protocols Standardized therapeutical protocols (treatment schemes) do not exist (treatment schemes) do not exist
Conservative treatment Pain management
At all stages, especially during blistering
(systemic analgesics and local cooling) Reduction of inflammatory reaction
antihistamines, NSAID, corticosteroids, aloe vera extracts
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Principals of treatment-IPrincipals of treatment-III
Conservative treatment Healing acceleration
occlusive dressings tetrachlorodecaoxide (TCDO) induces granulation
and re-epithelization in erosive skin conditions
Wound cleaning and prevention of infection antiseptic solutions (boric acid), for ruptured
blisters and vesicles neomycin- coated dressing local and systemic antibiotics only for secondary
infections
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Principals of treatment-III
Conservative treatment Improvement of local microcirculation
use of systemic vasodilators questionablepentoxifylline-trental hyperbaric oxygen therapy
Late phase: lesions are susceptible to reopening due to progressive vasculitis avoidance of trauma, rehabilitation,skin hydration use of drugs to reduce fibrosis
interferon-gamma superoxide dismutase
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Surgical treatment-ISurgical treatment-I
Opening overstretching blisters and vesicles if necessary, but increases pain and risk of
secondary infection
Reconstructive and plastic surgery excision of necrosis full thickness grafting myocutenous flap or pedicle flap
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Surgical treatment-II
Indications for amputation very severe lesions with destruction
of underlying tissue, including vascular damage
intractable pain lack of infection control
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ConclusionConclusion
Local radiation injury (or CRS) is a complex pathological syndrome that follows a typical clinical course characterized by excessively prolonged or incomplete healing
Long term and careful clinical observation and evaluation of perfusion and tissue necrosis by scintigraphy, thermography, cutenous laser doppler, CT and MR is essential