適當降低核醫藥物劑量的給予對影像攝取品質的影響

The Effect of Appropriately Reducing the Dose of Nuclear Medicine on the Quality of Image Uptake

目的：利用核子醫學與同位素藥物來做為疾病的診斷和治療已經有幾十年的歷史了。期間，核子醫學在技術和設備的精進與核醫藥物的不斷開發之下，使得可接受預防、診斷和治療的病灶越來越多。依照之前的文獻及臨床研究指出，核醫藥物劑量與影像攝取品質在核子醫學影像學的因果關係中，扮演了一個相對平衡的角色。本研究所提出的一個假說是：若在可接受的範圍之內，適時與適當的降低所給予受檢病人核醫藥物劑量，是否可以增加攝取影像的品質，並且降低和減少受檢者的輻射劑量與傷害。方法：實驗是經由大鼠股靜脈注射相同濃度、不同劑量的放射性同位素（free 99mTc），主要觀察與探討的目的為，在同一時間狀況之下：1. 低劑量、標準劑量和高劑量的核醫藥物在靜態影像攝取與時間的關係。 2. 將此注射三種不同濃度劑量free 99mTc 的大鼠，以時間計算為基礎；運用核子醫學的方式擷取其動態影像，觀察注射低劑量free 99mTc的大鼠；影像擷取品質是否與注射標準劑量和高劑量的同位素相同或是更好。 3. 最後，注射低劑量、標準劑量和高劑量的free 99mTc 後，其藥物留置器官所產生的輻射效應對影像攝取品質的影響。結果：實驗結果顯示，大鼠在低劑量的核醫藥物給予之後的六小時（一個半衰期），所得到的靜態影像與標準劑量和高劑量free 99mTc 攝取影像相比較之下，其週邊器官對主要器官的攝取影響較小，影像品質更好。但是，所消耗的攝取時間相對增加。而動態影像的結果亦與靜態影像相同，但是，整體攝取率卻較靜態影像來的差。討論：經由影像結果，我們認為所提出的適當的降低所給予受檢病人核醫藥物劑量在靜態影像攝取上，確實可以得到較好的效果。而在動態影像攝取方面，若能夠將 儀器取像由時間數改為total counts 數，則所得到的影像效果將會和靜態影像相當。

 

Objective: Diagnosis and treatment which make use of nuclear medicine and radiopharmaceutical to be used as disease have already for several decades. The nuclear medical science is in the technique and the equipment of aggressive with radiopharmaceutical develop continuously, make the focus that can accept prevention, diagnosis and treatment more and more. According to previous reference and clinical research, checking the nuclear medicine dose takes the cause and effect relation that the quality learns at the nuclear medicine image, played a role of opposite balance. This research is proposed a hypothesis: If in the acceptable scope, well timed and appropriate of reduce nuclear medicine dose administration to patients as low as possible, which can increase image quality. On the other hand, reduce with the hurt of patients by radiation. Methods: The experiment is through the big rat vein to inject a same density, and different dose of 99mTc. The mainly purpose is under same time condition to observe: 1. The relationship between the time and the static state image with nuclear medicine which measures with low, standard and high dose. Injecting three different kinds of dose which measure the free 99mTc to rats, takes “time calculation” as foundation. 2. The way which makes use of a nuclear medical science picks its dynamic image, observing rat of injecting the low doses 99mTc; The image picks quality whether with inject a standard the isotope homology for measuring of quantity and high or better. 3.End, after injecting the low, standard and high dose of free 99mTc, its medicine detention the radiation effect produced by organ takes the influence of quality to the image. Results: Test a result manifestation, rat at the low dose of nuclear medicine is administered after six hours (a half- life), which static image at standard and high dose with free 99mTc, for taking image mutually in comparison, the influence in the peripheral organ is smaller to the main organ, and the image quality is better. But, consume of uptake time opposite increment. And the result of dynamic state image are homology with the static image, but, total uptake rate is poor to static state. Conclusions: Through the image result, reducing of the adequacy that we put forward when thinking give to be subjected to check patient to check a medicine thing quantity to take in the static state image up, really can get better result. And in the dynamic state image, if we could take instrument to be like to change to a total count number from time number, the income result image will be equal with static state image in vivo.