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Biomedical subjects

J B Sasane

Publications and source records attributed to J B Sasane.

4 recordsLinked to original sources
PubMed1987

Volume correction factor in time dose relationships in brachytherapy.

Paterson's clinical data about the maximum tolerance doses for various volumes of interstitial implants with Ra-226 delivered in seven days was made use of in deriving volume correction factors phi v and phi'v for TDF and CRE concepts respectively for brachytherapy. The derived volume correction factors phi v for TDF and phi'v for CRE differ from the from the one assumed for CRE by Kirk et al. and implied for TDF by Goitein. A normalising volume of 70 cc has been suggested for both CRE and TDF concepts for brachytherapy. A table showing TDFv, the volume corrected TDF, is presented for various volumes and dose rates for continuous irradiation. The use of this table is illustrated with examples.

Brachytherapy↗
PubMed1981

Relevance of radiation penumbra in high-energy photon beam therapy.

In external beam therapy, radiation penumbra is one of the factors which hinder the confinement of the dose to tumour volume and cause unnecessary irradiation of the surrounding normal tissues in the penumbral region. In the present work, the magnitudes of radiation penumbras were evaluated for various high-energy X-ray beams and cobalt-60 beams, from their respective isodose charts, at the depth of maximum ionization (dmax) and at the typical tumour centre depth of 10 cm (d10) and for field sizes of 5 x 5 cm2, 10 x 10 cm2 and 15 x 15 cm2. Although the radiation penumbra for high-energy X-ray beams up to 16 MV was found to be smaller in comparison with cobalt-60 beams, at 20 MV and beyond it tends to increase and becomes comparable to that for cobalt-60 beams. In the light of this comparison and the results of some of the cancer treatments with high-energy beams reported by various authors, the relative importance of radiation penumbra and integral dose in the treatment volume is discussed.

Cobalt Radioisotopes↗
PubMed1979

Isoeffect lines using TDF and CRE concepts.

In most of the radiotherapy centres the treatment planning is based on isodose lines. Isoeffect lines are also being drawn based on the concepts of TDFs and CREs. It was aimed in this work to find out whether the isoeffect lines based on the concepts of TDFs, CREs and the physical isodose lines are identical in all the treatment situations. Isoeffect lines for a few treatment schedules involving treatment of carcinoma of the bladder, treatment of cancer of the uterine cervix by combined intracavitary and external beam therapies and intracavitary therapy alone have been obtained and compared in the present study. The effect of treatment mode on the isoeffect lines is also studied. It is found that the isodose curves and the isoeffect lines using the TDF and CRE concepts are not identical in all situations. Therefore, the ultimate treatment plans based on theses isoeffect lines will not be exactly the same. The dependence of the isoeffect lines with the variation of the exponents of time and number of fractions used in the empirical relationship for NSD have also been investigated. Clinical trials have been initiated in the case of cancer of the bladder and cervix uterus based on the isodose curves and the isoeffect lines using CRE and TDF concepts.

Cobalt Radioisotopes↗