Radio Therapy - Benefits and Uses of Radio Therapy
X-rays or Roentgen rays are rays of very short wave-length (shorter than 100A degree units). They are produced by bombardment of electrodes from a cathode filament to an anode tungsten plate at a high voltage and the resultant X-rays are emitted through a window. The present machines are shock-proof, and ensure a great deal of protection from scattered X-rays. The quantity and quality of X-rays reaching the site at different voltage (kV), milliamperes (mA) and distances are measured and charted for each machine. The unit of Roentgen ray quantity measure is called a Roentgen (r). The epilation or erythema dose is the skin toleration dose (400 r for unfiltered radiation at 90 kV).
Depth, Dose Data (after zoon and zerry Modified)
Epidermis
Hair papilla
Corium
Sweat glands (Eccrine)
Derm. and eczema
Psoriasis
Lichen simplex chronicus
Lichen planus
Folliculitis and acne
Basal cell epithelioma
Squamous cell epithelioma |
0.03 to 0.25 mm
2.5 to 3.5 mm
3.0 to 4.0 mm
2.0 to 4.0 mm
0.8 to 2.0 mm
0.7 to 3.0 mm
1.0 to 4.0 mm
0.4 to 2.0 mm
3.0 to 6.0 mm
2.0 to 5.0 mm
3.0 to 10.0 mm |
High voltage Betatron has been employed with success in exfoliative dermatitis and intractable erythroderma.
The physio-biological effects of radio-therapy are:
1. Reduction of rate of cell division or even temporary cessation
2. Reduction of secretion.
3. Reduction of sensitivity in nerve endings.
4. Reduction of bacterial and fungal growth.
5. Permanent killing of cells.
Indications for Radiotherapy
|
Disease |
Indications |
Dosage |
Total radiation |
A |
Benign |
|
|
|
1 |
Acne vulgaris |
Chronic pustular or keloid/cystic acne |
75 r weekly |
1000 r in 6 months |
2 |
Keloid |
Not hard, more vascular rather less fibrotic; less than 9-2 months duration |
300 r alternate days or weekly |
1500 r |
3 |
Ch. Eczema |
Chronic, resistant |
75 r weekly |
800 r |
4 |
Paronychia |
Chronic, persistent |
75 r weekly |
400 r |
5 |
Heemangioma |
Strawberry/cavernous |
250 r fortnightly or monthly |
500-75o r |
6 |
Warts |
Periungual, subungual, plantar |
750 r monthly |
1500 r |
7 |
Lichen simplex chronicus |
Marked lichenification long standing, resistant to topical steroids |
100 r weekly |
800 r |
8 |
Dermal leishmaniasis |
One or two areas, resistant to routine therapy |
600 r one dose |
600 r |
9 |
Pustular psoriasis dyshidrosis |
Resistant, recalcitrant |
50-75 r weekly |
500 r |
10 |
Hypertrophic lichen planus |
Recalcitrant cases |
100 r weekly |
800 r |
11 |
Lymphocy-toma cutis |
|
100 r weekly |
1000 r |
B |
Malignant |
|
|
|
12 |
Basal cell epithelioma |
Avoid cartilaginous areas, scrotum and eyes |
400 r alt. day |
3000 r |
13 |
Squamous cell epithelioma |
|
500 r alt. day |
4000 r |
14 |
Kaposi"s haemorrhagic sarcoma |
Skin lesions |
100 r weekly |
800-1000 r |
15 |
Lymphomas (esp. mycosis fungoides) |
|
300 r alt. day |
3000 r |
Grenz rays are useful in resistant cases of pruritus ani, vulvae, scrotum; dyshidrosis; psoriasis and balano-posthitis.
Definite contra-indications are:
1. Light-sensitive dermatoses, lupus erythematosus etc.
2. Acute eczema.
3. Radio-dermatitis, ulcer, atrophy and epithelioma.
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