We have evaluated the merits of X-ray cine sensitometry using the aluminum(Al) stepwedge bootstrap method, with a comparison of the N.D.filter method. In this study, multipler exposure for bootstrap sensitometry obtained by changing of the mAs value (Method 1), or using the N.D.Filter (Method 2). The shape of characteristic and gradient curves obtained from Method 1 or 2 were almost the same as that the using N.D. filter method. In addition, the average gradients of the characteristic curve for both of the Al stepwedge bootstrap method showed no difference from that of the N.D. filter method. These results suggest that both the Al stepwedge bootstrap methods are able to be applied to X-ray cine sensitometry. In X-ray cine sensitometry, these two Al stepwedge bootstrap methods were much easier to carried out than N.D. filter method.
