Evaluation of incorporated iododeoxyuridine cellular radiosensitization by photon activation therapy

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(87)90194-5· OSTI ID:6368939

Miller, R W; DeGraff, W; Kinsella, T J; Mitchell, J B

Halogenated pyrimidines such as iododeoxyuridine (IdUrd), when incorporated into cellular DNA, sensitize cells to radiation. A technique known as photon activation therapy (PAT) has recently been proposed to further enhance IdUrd radiosensitization. This approach relies on the emission of high linear energy transfer Auger electrons as a result of photoelectric absorption of photons with energies slightly above the K shell binding energy for iodine. Thus, additional IdUrd radiosensitization has been predicted for this technique using photons either generated externally from orthovoltage units or with implants of radioisotopes with emissions of the appropriate energy range. We have tested this prediction by comparing the radiosensitization of Chinese V79 cells, which have incorporated IdUrd (16% replacement of thymidine with IdUrd), to megavoltage (15 MV) versus orthovoltage (100 KVp) radiation. Enhancement ratios at 1% survival levels for 15 MV vs. 100 KVp radiation were 1.8 and 1.95, respectively. This modest 10-15% additional enhancement was much less than that predicted by PAT. The discrepancy between experimental data and the theoretical predictions of PAT are discussed.

• Research Organization: National Cancer Institute, Bethesda, MD
• OSTI ID: 6368939
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 13:8; ISSN IOBPD
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
ANTIMETABOLITES
AZINES
BODY
DEOXYURIDINE
DNA
DRUGS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY TRANSFER
FERMIONS
HAMSTERS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IN VITRO
LEPTONS
LUNGS
MAMMALS
MASSLESS PARTICLES
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PHOTONS
PYRIMIDINES
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RESPIRATORY SYSTEM
RIBOSIDES
RODENTS
URACILS
VERTEBRATES