Evaluation of time-dose and fractionation for sup 252 Cf neutrons in preoperative bulky/barrel-cervix carcinoma radiotherapy

Journal Article · Sat Dec 01 04:00:00 EST 1990 · International Journal of Radiation Oncology, Biology and Physics; (USA)

DOI:https://doi.org/10.1016/0360-3016(90)90373-R· OSTI ID:6146490

Maruyama, Y; Wierzbicki, J ^[1]

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1. Univ. of Kentucky Medical Center, Lexington (USA)

Time-dose fractionation factors (TDF) were calculated for 252Cf (Cf) neutron therapy versus 137Cs for intracavitary use in the preoperative treatment of bulky/barrel-shaped Stage IB cervix cancers. The endpoint assessed was gross and microscopic tumor eradication from the hysterectomy specimen. We reviewed the data obtained in clinical trials between 1976-1987 at the University of Kentucky Medical Center. Preoperative photon therapy was approximately 45 Gy of whole pelvis irradiation in 5 weeks for both 137Cs and Cf treated patients. 137Cs implant was done after pelvic irradiation x1 to a mean dose of 2104 +/- 36 cGy at point A at a dose rate of 50.5 cGy/h. There were 37.5% positive specimens. Using Cf intracavitary implants, dose varied from 109 to 459 neutron cGy in 1-2 sessions. Specimens were more frequently cleared of tumor (up to 100% at appropriate dose) and showed a dose-response relationship, both by nominal dose and by TDF adjusted analysis of dose, dose-rate, number of sessions, and overall time. Limited understanding of relative biological effectiveness, schedule, effect of implants, and dose rate all made it difficult to use TDF to study neutron effects. Relative biological effectiveness (RBE) was estimated and showed that for Cf, RBE was a complex function of treatment variables. In the pilot clinical studies, a value of 6.0 had been assumed. The present findings of RBE for tumor destruction are larger than those assumed. Cf was effective for cervix tumor therapy and produced control without significant side effects due to the brachytherapy method used. The TDF model was of limited value in the present analysis and more information is still needed for RBE, dose-rate, and fractionation effects for Cf neutrons to develop a more sophisticated and relevant model.

• OSTI ID: 6146490
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (USA), Journal Name: International Journal of Radiation Oncology, Biology and Physics; (USA) Vol. 19:6; ISSN 0360-3016; ISSN IOBPD
• Country of Publication: United States
• Language: English

Related Subjects

550603* -- Medicine-- External Radiation in Therapy-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALKALI METAL ISOTOPES
ALPHA DECAY RADIOISOTOPES
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALIFORNIUM 252
CALIFORNIUM ISOTOPES
CARCINOMAS
CESIUM 137
CESIUM ISOTOPES
DISEASES
DOSE-RESPONSE RELATIONSHIPS
DOSES
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FEMALE GENITALS
FERMIONS
FRACTIONATED IRRADIATION
HADRONS
HEAVY NUCLEI
IRRADIATION
ISOTOPES
MASSLESS PARTICLES
MEDICINE
NEOPLASMS
NEUTRONS
NUCLEAR MEDICINE
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
ORGANS
PHOTONS
RADIATION DOSES
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
RBE
THERAPY
UTERUS
YEARS LIVING RADIOISOTOPES