Neutron-capture therapy

Such unique procedure as neutron-capture therapy of inoperable tumours of complex localization of head and neck which resist to other methods of treatment is only possible in Clinic “BIOCONTROL” at joint participation of Moscow Engineering and Physics Institute. The article describing the developed study is published in the magazine “Scientific American” N3, March, 2005 (Russian version).

NEURON-CAPTURE THERAPY IN DOGS WITH SPONTANEOUS MELANOMA OF ORAL CAVITY

Clinic of experimental therapy of N.N. Blokhin

Russian Oncological Science Center of Russian Academy of Medical Science Russian Institute of biophysics of Russian Academy of Science

Moscow Engineering and Physics Institute

Frequently marked melanoma in dogs

• 31-52% — tumours of oral cavity mucosa
• 2-9% — all tumours

Traditional treatment methods

• Distance gamma-therapy
• Chemotherapy

Surgical tumour removal is often impossible because of localization.

For efficiency of tumour treatment a method resulting in tumour cell selective affection with normal tissue preservation is required.

Neuron-capture therapy (NCT) is a complex bimodal form of radiotherapy

Studies were made on basis of IRT MIPHI.

Method:

Barium and gadolinium are injected into tumour and then it is irradiated with thermal neutron beams of high intensity.

As a result of capture of thermal neutrons there is a secondary radiation affecting tumour cells.

• Normal cells and tumour cells
• Selective tumour or cell absorption of atoms 10B
• Thermal neutron irradiation

Result Ions 4He2+ and 7Li3+ formed during neutron-capture reaction move in tissues approximately for diameter of one cell. Along movement trajectory they cause ionization of molecules.

Neutron-capture therapy (NCT) NCT types:

• Barium-NCT with 10B (barium-L- phenylalanine medication) i.v. (BNCT) 10B-L- phenylalanine complex
• Gadolinium-NCT with 157Gd (Dipentast) into tumour (GNCT) Gadolinium GdH2dtpa complex

Barium-L- phenylalanine inclusion in synthesis of melanin L- phenylalanine Melanin, barium inclusion 10B-L- phenylalanine L-thyrozine

Study purpose

To define the efficiency of NCT application (BNCT and GNCT) in dogs with spontaneous melanoma of oral cavity mucosa

Neutron-capture therapy (NCT) Study was made in dogs ranged from 9 up to 15 years with histological confirmed melanoma of oral cavity mucosa.

• First group – gamma-therapy (7 animals)
• Second group – BNCT (15 animals)
• Third group – GNCT (7 animals)

Ronkoleikin medication was applied in all dogs as adjuvant therapy.

Study results

• First group

Recurrences were marked in 90% dogs in 1 month after treatment, metastases – in 2-3 months.

Life time – 3 months.

• Second group – BNCT

95% — full tumour regression 20% — recurrences in 3-4 months.

Life time – 8 months.

• Third group – GNCT

70% — full tumour regression during 30-45 days 14% — recurrences in 1 month.

Life time – 4-6 months.

BNCT

Animal before BNCT and in 1 year after BNCT

GNCT

S. Redgy T3bNOMO – IIB

16.02.05 – gadolinium neutron-capture therapy. Full regression. Recurrence-free period – 8 months.

Conclusions:

• Tumour has disappeared within its bound during NCT and medical treatment was possible for unresectable tumours.
• Patient life time and recurrence-free period in NCT (BNCT and GNCT) was longer than in patient of gamma-therapy. (Total radiation responses are expressed more in pigment animals and predominantly pigmented tissues were affected).
• NCT is more effective in incurable cases when traditional treatment methods have no desirable results.