PROBLEM TO BE SOLVED: To solve the problem that, the smaller a tube current and an imaging time are, the larger deviation from an actual measurement value is, because a quantity of radiation is calculated using a calculating formula assuming that the quantity of radiation is proportional to the tube current and imaging time in an X-ray high voltage device having capability to calculate the quantity of radiation on the basis of an imaging condition.SOLUTION: As a calculating formula, a dosage characteristic constant DT (V) of a term corresponding to the quantity of radiation of an X-ray irradiated as a wave tail X-ray is added to an existing term in proportion to a tube current and an imaging time, and the DT (V) and the dosage characteristic coefficient Dt (V) of the term in proportion to the tube current and the imaging time is beforehand stored in a DT (V) memory 14 and a Dt (V) memory 15, respectively. Then, a computational part 16 calculates the quantity of radiation from the calculating formula using the imaging condition obtained from an X-ray controller 3 at the setup time of the imaging condition and memory values stored in both the memories.COPYRIGHT: (C)2008,JPO&INPIT【課題】撮影条件から照射線量を算出する機能を有するX線高電圧装置において、照射線量が管電流と撮影時間に比例することを前提とした計算式により照射線量の算出を行っていたので、管電流が小さいときほど、また撮影時間が短いときほど実測値とのずれが大きくなっていた。【解決手段】計算式として従来の管電流と撮影時間に比例する項に波尾X線として照射されるX線による照射線量に対応する項の線量特性定数DT(V)を追加し、管電流と撮影時間に比例する項の線量特性係数Dt(V)とともに、事前にそれぞれDT(V)記憶部14およびDt(V)記憶部15に記憶しておき、撮影条件設定時にX線制御器3から得られる撮影条件および両記憶部の記憶値を用いて演算部16が計算式により照射線量を算出する。【選択図】 図1
