1975, British Journal of Radiology, 48, 1023-1024


Technical notes A table for the comparison of commonly-used fractionation schemes in radiotherapy By C. E. Revers, M.D., and A . Hasman, Ph.D. Department of Radiotherapy, Academisch Ziekenhuis der Vrije Universiteit, Amsterdam, The Netherlands {Received December, 1974 and in revised form June, 1975)

The NSD formula of Ellis (1968) is useful in comparing different fractionation schemes, even when the comments of Liversage (1971) and Berry, Wiernik and Patterson (1974) are taken into consideration. For the application of this formula the Oxford NSD calculator (Winston, Ellis and Hall, 1969), the table of Kroening and Deiterman (1971), the tables of Orton and Ellis (1973) and the graphs of Armstrong (1974) are available. However, in daily practice many radiotherapists may find it time consuming to use these methods. We use one table (Table I) from which can be read directly the values of rets and rads for the commonly-used fractionation schemes. These values have been calculated by computer on the basis of the NSD formula.

In complicated fractionation schemes one should, however, use the expedients of the above mentioned authors, the slide-rule of Eads (1972) and the table of Phelps and Phelps (1974). ACKNOWLEDGMENTS

The authors thank Professor P. J. L. Scholte, M.D., Ph.D. and F. Karim, F.R.C.R. for their valuable suggestions and help. REFERENCES ARMSTRONG, D. I., 1974. N.S.D. calculation, a simple graphical method. British Journal of Radiology, 47, 363. BERRY, R. J., WIERNIK, G., AND PATTERSON, T. j . S., 1974.

Skin tolerance to fractionated X-irradiation in the pig. How good a predictor is the N.S.D. formula? British Journal of Radiology, 47, 185-190. EADS, D. L., 1972. Application of a ret-dose slide rule relating dose, time, area-volume, quality and anatomic




2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000

1,170 1,460 1,750

1,100 1,380 1,650 1,930 2,200

1,000 1,250 1,500 1,750 2,000

1 week 2 weeks 3x 5 X /w 2 x Rets 1,960 1,920 1,770 1,730 1,580 1,540 1,370 1,330 1,140 1,100 880


1,100 1,330 1,420 1,290 1,140 RADS RETS 1,550 1,660 1,500 1,330 1,490 1,350 1,200 1,770 1,890 1,720 1,520 1,700 1,550 1,370 2,130 1,930 1,710 1,920 1,740 1,540 1,770 1,600 1,420 2,130 1,930 1,710 1,960 1,780 1,580 1,850 1,650 1,500 2,160 1,960 1,730 2,020 1,840 1,620 1,540 2,340 2,140 1,890 2,220 2,000 1,770 1,680 2,405 2,170 1,920 1,820 1,960



5 weeks

4 weeks

3 weeks 5x






7 wk

6 weeks







4,960 4,850 4,400 4,290

7,000 5,190 5,750 6,500 6,870 5,610 4,780 5,300 6,000 6,330 5,500 4,700 5,180 5,860 6,180 5,000 4,270 4,790 5,270 4,850


1,950 1,890 1,510

3,230 2,470 2,720 3,070 2,870 2,410 2,660 3,010 2,810 2,070 2,280 2,580 2,410 2,000 2,200 2,500 1,600 1,760 2,000

3,560 3,170 3,100 2,650

3,680 4,030 3,590 3,580 3,190 3,500 3,120 3,000

4,540 4,400 4,060 4,590 3,990 3,960 4,500 3,940 3,520 4,000 3,440 3,890 RETS RADS

The upper table "RADS - RETS" gives the NSD in rets for the commonly used rad doses with different fractionation schemes, namely 2, 3 or 5 fractionations per week in different elapsed periods. The ret doses in italics are assumed to be used more regularly. For these doses one may use the lower table "RETS - RADS" to get the rad doses in different fractionation schemes. An example: 6,500 rads in six weeks with 5 f/w delivers 1,920 rets, as shown in the upper table. The lower table reveals that the same ret dose may be delivered in six weeks with 3 f/w by 5,750 rads, with 2 f/w by 5,190 rads, or in seven weeks with 5 f/w by 6,870 rads. 1023

1975, British Journal of Radiology, 48, 1024-1026 Technical notes factors. In J. M. Vaeth, Frontiers of radiation therapy and oncology, Ed. Karger (Basel), pp. 108-142. ELLIS, F., 1968. The relationship of biological effect to dose time fractionation factors in radiotherapy. In Current topics in radiation research, Ed. Ebert and Howart, Vol. 4, pp. 357-397 (North Holland Publishing Company, Amsterdam). Kroening, P. M., and Deiterman, L. H., 1971. A table for the normalization of time-dose relationships. American Journal of Roentgenology, 112, 803-805.

LIVERSAGE, W. E., 1971. A critical look at the ret. British Journal of Radiology, 44, 91-100. ORTON, C. G., and ELLIS, F., 1973. A simplification in the

use of the N.S.D. concept in practical radiotherapy. British Journal of Radiology, 46, 529-537. PHELPS, H. M., and Phelps, C. E., 1974. Tables for calculation of nominal standard dose for complex treatment schedules. Radiology, 111, 411-414. WINSTON, B. M., ELLIS, F., AND HALL, E. J., 1969. The

Oxford N.S.D. calculator for clinical use. Clinical Radiology, 20,8-11.

Ultrasonic investigation of inferior vena-caval obstruction By K. J. W. Taylor, B.Sc, M.B., Ph.D.* Royal Marsden Hospital and Institute of Cancer Research, Sutton, Surrey (Received January, 1975)

The terminal portion of the inferior vena cava can be visualized by ultrasound in every patient, and frequently the entire longitudinal extent of the vessel is apparent. Holm (1970) reported that the variation in the lumen of the inferior vena cava could be displayed by time-position mode (TP, TM or M mode) but the method does not appear to have been applied to the investigation of inferior vena-caval (IVC) obstruction. A custom-built grey-scale equipment was used in these investigations but the method should be effective with less sophisticated scanners. The inferior vena cava is visualized on a longitudinal parasagittal section through the liver substance about 2 cm to the right of the midline using the technique described previously (Taylor and Hill, 1975). The resultant scan is shown in Fig. 1 and an apparent constriction is commonly produced due to missing the precise plane of the vessel. This can be differentiated from a true obstruction by the method described below. The ultrasound beam is directed immediately below the apparent obstruction and the scanner changed to TP mode. Using this display, the lumen of the vena cava is shown and its variations with time. Figure 2 shows that the caval lumen displays two distinct oscillatory cycles: those of the respiratory and cardiac cycles. Small oscillations are associated with the heart beat (C) and since these persist even in IVC obstruction, they must be transmitted from the neighbouring aorta. The lumen of the IVC virtually collapses in the fit person lying in the supine position on inspiration. This is well seen in Fig. 2 and demonstrates the respiratory pump well. *Present address: Department of Diagnostic Radiology, Yale University, School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, U.S.A.

A number of abnormalities may be observed and their significance assessed. When the IVC is obstructed above the level of the ultrasound beam, the respiratory oscillation is absent and the cause should be apparent as seen for example in Fig. 3. This parasagittal ultrasonogram shows a large liver with an abnormally homogeneous consistency consistent with malignant replacement in chronic lymphatic leukaemia. This compressed the IVC producing bilateral leg oedema. A number of other causes have been seen including enlarged lymphnodes, pancreatic tumours and retroperitoneal masses, especially in the non-Hodgkin's lymphomata. Finally, one may see both respiratory and cardiac cycles present but the IVC lumen remains widely

FIG. 1. B-mode ultrasonogram of abdomen showing a parasagittal section 2 cm to the right of the midline. The inferior vena cava can be seen in longitudinal section (arrowed) with the liver (H) anterior to it.


A table for the comparison of commonly-used fractionation schemes in radiotherapy.

1975, British Journal of Radiology, 48, 1023-1024 DECEMBER 1975 Technical notes A table for the comparison of commonly-used fractionation schemes in...
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