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

Module Medical XIII.

2

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)

Module Medical XIII.

3

Common sources inducing radiation injury

192Ir 60Co 137Cs Fission products (beta exposure) 90Sr X-ray machines X-ray fluorescence Cyclotron products

Module Medical XIII.

4

Typical scenarios leading to partial body radiation injuries

finding lost unshielded sources

Module Medical XIII.

5

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”)

Module Medical XIII.

6

Severe radiation injury of hand - Algerian accident with lost 925 GBq (25

Ci) 192Ir source, 1978

Module Medical XIII.

7

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.

Module Medical XIII.

8

Factors determining severity of local radiation injuries

Module Medical XIII.

9

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

Module Medical XIII.

10

Human skin structureHuman skin structure

Module Medical XIII.

11

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

Module Medical XIII.

12Normal Irradiated

Module Medical XIII.

13

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

Module Medical XIII.

14

Blister formation

Module Medical XIII.

15

On right hand severe blisters developed after irradiation; on left hand epidermis has sloughed. Presence of hyaline fluid gives blisters translucent appearance

Moist desquamation

Module Medical XIII.

16

Ulceration and necrosis

Module Medical XIII.

17

Hyperpigmentation

Module Medical XIII.

18

Section of normal skin (left) and of healed lesion (right) from same bovine hide.

Module Medical XIII.

19

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

Module Medical XIII.

20

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

Module Medical XIII.

21

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

Module Medical XIII.

22

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

Module Medical XIII.

23

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

Module Medical XIII.

24

Contact Contact lliquid iquid ccrystalrystalththermographyermography

Module Medical XIII.

25

ThermographyThermography

Module Medical XIII.

26

ThermographyThermography

Module Medical XIII.

27

Perfusion Perfusion sscintigraphycintigraphy

Phase 1: Blood flow Phase 2: Blood pool

Module Medical XIII.

28

ThermographyThermography

Normal hand thermography

Module Medical XIII.

29

Later phase of clinical course:tthermographyhermography

Module Medical XIII.

30

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

Module Medical XIII.

31

Accident reconstruction

Module Medical XIII.

32

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

Module Medical XIII.

33

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

Module Medical XIII.

34

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

Module Medical XIII.

35

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

Module Medical XIII.

36

Surgical treatment-II

Indications for amputation very severe lesions with destruction

of underlying tissue, including vascular damage

intractable pain lack of infection control

Module Medical XIII.

37

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