Proceedings of the Symposium on Low level Electromagnetic Phenomena in Biological Systems, 3 & 4 February 1999, pp 68-72, Ed: Jitendra Behari, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067

POSSIBLE BIOLOGICAL EFFECTS by UV-RADIATION newly detected

FROM INTERNALLY ADMINISTERED RADIOISOTOPES

Notably from radioisotopes as well as characteristic X-ray sources the author reported to have discovered light emission predominant in ultraviolet (UV) radiation^1-4. Since it is not known earlier that UV radiation associates with ionising radiations in causing biological effects when radioisotopes such as ^99mTc, ¹³¹I, ²⁰¹Tl are internally administered into the body, the biological effects and conventional dose estimates to the bodily organs deserve a thorough review.

INTRODUCTION

Henry Becquerel discovered radioactivity in 1896 from the naturally occurring phosphorescent potassium uranyl sulphate^.5. Similarly radium (present as chloride) discovered from the uranium ore, pitchblende by Pierre and Marie Curie in 1898 has also been a radioactive and feeble self-luminescent material⁶. Then came the artificially produced radioisotopes discovered on alpha irradiation by Irene Curie and Fredric Joliot in 1933 followed by neutron irradiated and cyclotron produced radioisotopes. But their emission of any phosphorescence or fluorescence was neither reported nor predicated by earlier researchers. In these circumstances, from all the radioisotopes investigated the author discovered incredibly very poor fluorescent light emission, which is neither visible to the naked eye nor can be explained by any known phenomenon^1-4.

Radioisotope and X-ray sources are examples of an immensely important family of ionising radiation sources, yet a big distinction persists between the two. However light emission has also been discovered from X-ray sources, say along with Cu, Rb, Mo, Ag, Ba, or Tb X-rays from Cu (metal), rubidium sulphate, Mo (metal), Ag (metal), barium oxide, or terbium peroxide respectively on g-excitation from ²⁴¹Am [AMC 2084, Amersham International, U.K.]. Earlier to this, no literature is available on light emission either from an X-ray tube or characteristic source ever since the discoveries of X-rays (bremsstrahlung) from Crook’s tube by W.C. Roentgen and characteristic X-rays of elements by Charles Glover Barkla. The light observed as a common emission from both X-ray and radioisotope sources led to a fundamental finding that light photons follow X-, and g-rays, and b-particles from one and the same excited atom that can have a great significance in atomic and nuclear sciences. For example, within ¹³¹I atom its b, g, and Xe X-ray emissions independently produce room-temperature fluorescent light photons. Also has been found, from all the radioisotopes tested, a complete range of optical spectrum including ultraviolet (UV), visible (VIS), and near infrared (NIR) radiations. Since most of their light emission lies in UV range [up to 400 nm], which causes biological effects the insight is noteworthy to radiobiologists.

Most interestingly, from ¹³¹I and ¹³⁷Cs the light protons were found exceeding g-ray photons when counted by a high gain photo multiplier tube (9635QB, THORN EMI) and a scintillation detector respectively. In clear words, they have been found as good light and UV emitters over other radioisotopes tested. ¹³¹I accumulates mainly in the thyroid gland, but does even in total body, gastrointestinal tract and lungs due to diagnostic and therapeutic procedures or accidental exposure^7-9. Most importantly, the new insight on UV radiation emission challenges the radiation dose estimates which relied only on b-particles, g-, and Xe X-ray and conversion electron emissions^10-13. Unfortunately, the current wisdom on biological effects of UV radiation is limited to external exposure, for example, proteins inducing free radicals, gene activation, haemolysis, skin cancers, and effect in intact eye lens^14. It is the hope that the new insight would prompt the readers to

Fig.1. In a beam of visible (VIS) light, they transmitted a low percent of incident light, which has been plane polarised light in the visible range from 400-710 nm, and near infrared (NIR) radiation which began to increase rapidly from nearly 710 nm onwards. On rotating one of the sheets to 90° (crossed pair), the amount of light transmitted in the near infrared region has been just about the same as when the two plates were parallel while the second sheet behind eliminated the polarised visible light transmitted by the first sheet.

investigate whether UV radiation is responsible in causing any biological damage to the cells unknown so far when associated with ionising radiations. The author speculates that the cells and bodily organs would also be exposed to different energies by a new atomic phenomenon termed Rao (Padmanabha Rao) effect^1-4. The author postulated that when ionizing radiation passes through charged space around a core electron causes low energy electromagnetic radiation with energy higher than that of UV radiation in eV level termed ‘Bharat radiation’. Also postulated that it in turn excites valence electron and causes fluorescent light emission⁴. To sum up, ionizing radiation, Bharat radiation and fluorescent light follow one after another from one and the same radioactive atom. Currently no detector is available to detect the Bharat radiation. Since the intensity of light from any radioisotope depends upon the type and energy of ionizing radiations, cellular exposures to optical radiation differ from one radioisotope to the other for the same activity level. Anyhow, the purpose of this paper is to prompt the readers to probe further on the biological effects, if any caused by the Bharat radiation emission.

EXPERIMENTAL

In the current study, a PMT coupled to a ‘preamplifier served uniquely as a sensor not only to the light but also b-particles¹⁵, X-rays and g-rays, on connecting through a linear amplifier to an 8K MCA. The PMT was housed in a metal casing with a lid. And prior to the opening of the lid for replacing a source with another, terminated high voltage supply to the PMT. Also the experiment was conducted in dark room to prevent the PMT from possible light leak, if any. For each photon or particle detected the PMT sends a single photocathode pulse. Eventually the MCA displays pulse height spectrum devoid of any peaks for the radiation intensity that the PMT detected. Therefore, integral counts were noted for 4 min. and shown in Table 1 in terms of counts sec^-1 (cps). Gain of the linear amplifier had to be set higher than what is usually required for a g- or b-spectrometer, and the time constant at 0.1 m sec. Radioisotopes were procured from the Board of Radiation and Isotope Technology, Mumbai. Thin Mylar film fixed in front of the radioisotopes had to be removed to permit light transmission.

Use of a pair of sheet polarizers of the type described by Robertson¹⁶ not only confirmed the said light emission also facilitated in estimating the contributions of UV, VIS, and NIR radiations. On keeping the pair in a beam of UV-radiation, they showed opacity (Fig.1). In a beam of visible (VIS) light, they transmitted a low percent of incident light, which has been plane polarized in the visible range from 400-710 nm, and near infrared (NIR) radiation which began to increase rapidly from nearly 710 nm onwards. On rotating one of the sheets to 90° (crossed pair), the amount of light transmitted in the near infrared region has been just about the same as when the two plates were parallel while the second sheet behind eliminated the polarized visible light transmitted by the first sheet (fig.2).

A NEW METHOD FOR MEASUREMENT OF LIGHT

The following method developed by the author served commonly for all the sources. ¹³⁷Cs (^137mBa) exemplifies a source with three types of ionizing radiations (IRs) namely b-particles, g-rays, as well as Ba X-rays. Step (a): On keeping the source directly over quartz window of the PMT, 9098 ± 6.2 cps have been observed. These counts were attributed due to light as well as IRS that were detected. Step (b): A pair of sheet polarizers in parallel position were interposed between the source and the PMT. Fig.1 shows that these sheets do not allow

Fig.2. A schematic diagram of the experimental set up used for confirmation of light emission and measurement of ultraviolet [UV], visible [VIS] and near infrared [NIR] radiations observed along with ionizing radiations (IRs) from ¹³⁷Cs. Photo multiplier tube served as sensor to both light and IRs.

Table1. Intensities of ultraviolet (UV), visible (VIS), and near infrared (NIR) radiations and light (UV+VIS+NIR radiations) measured from each radioisotope source in terms of counts per sec (cps), using photo multiplier tube (9635QB, THORN EMI) as sensor .²⁰¹TI, ¹³¹I, and ^99mTc are important internally administrated radioisotopes.

The counts given here are corrected for background level (13 cps) of the photo multiplier. Cu, Rb, Mo, Ag, Ba, and Tb targets (AMC 2084) are Cu, Rb, Mo, Ba and Tb X- .ray sources. Cu, Mo and Ag targets; ⁵⁷Co* and ⁶⁰Co* showed light emission notably at room temperature though in metal form.

transmission of UV radiation to PMT, but allow visible (VIS) light which is polarized, NIR and IRs that caused 793 ± 3.6 cps. Therefore the difference in counts, 8305 ± 5.0 cps estimated from steps (a-b) was attributed to the UV radiation detected. Step (c): On rotating one of the sheets to 90° (crossed pair), the sheets do not transmit visible (polarized) light but transmit only the NIR and IRs, which caused 720 ± 3.5 cps. Notably, the fall of counts noticed by mere rotation of a sheet due to elimination of visible light confirms emission of visible light. The difference in counts 73 ± 2.9 (Table 1) are thus due to visible (VIS) light emission. Step (d): A 0.26 mm thin black polyethylene sheet was introduced between sheets and the PMT to exclude even NIR radiation, but to allow IRs that caused 519 ± 2.9 cps. The difference in counts, 201 ± 2.3 cps (Table 1) by Steps (c-d) are thus due to NIR radiation.

Similarly from the rest of the sources listed in Table 1 including the internally administered radioisotopes like ^99mTc, ¹³¹I and ²⁰¹Tl, the contribution of UV radiation ranks very high, while low for the visible and very low for the near infrared radiations. Accurate methods can follow on estimation of UV intensities for the same activity level from the desired internally administered radioisotopes. To conclude that this new insight study may prompt the readers to review the biological effects and radiation dose estimates in internal dosimetry.

Acknowledgement

The author gratefully acknowledges the kind assistance of Dinesh Bohra and Arvind Parihar for conducting experiments initially concerning this work. The experimental work was done at the Defence Laboratory, Jodhpur, 342001, India,where the author worked formerly as Deputy Director.

References

1 M A Padmanabha Rao, (1997) Atomic emission of light from sources of ionizing radiation by a new phenomenon, Technical Report No: DLJ/ IL/ 97/ 7 (Defence Laboratory, Jodhpur 342011, India, April 1997).

2 M A Padmanabha Rao, (1997) Light emission observed from ionizing radiation sources by an atomic phenomenon, Paper presented at the National Symposium on Contemporary Physics: Some Aspects, Organized by the Indian Physics Association, Physics Department, Presidency College, Calcutta, India, November 6-8.

3 M A Padmanabha Rao, (1998) Radioisotopes and X-ray sources emit fluorescent light by an atomic phenomenon, Proceedings of the 12^th National Symposium on Radiation Physics, (eds. P K Bhatnagar et al), Sponsored by Indian Society for Radiation Physics, Defence Laboratory, Jodhpur 342011, India, pp 273-276, and January 28-30 (Publisher: Hindustan Enterprises, Jodhpur 342003, Rajasthan, India).

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