JPH0752240B2 - ▲ Top 9 ▼ ▲ Top 9 ▼ ▲ Top m ▼ Tc generation / attenuation display device - Google Patents

Description

BACKGROUND OF THE INVENTION (FIELD OF THE INVENTION) The present invention, in the ^99m Tc generators, ^99m Tc generator attenuation that can know the amount of radioactivity and recovery rate of ^99m Tc generator after milking of ^99m Tc in Riatsutaimu The present invention relates to a display device.

(Prior Art) For example, it is widely known that ^99m Tc as a ^{radiopharmaceutical} solution is used for diagnosis of brain tumors and cerebrovascular accidents. This ^99m Tc was prepared by adsorbing ⁹⁹ Mo (half-life: 66.7 hours) as a nucleophile to a column of alumina for radiation equilibrium (transient equilibrium), and eluting it with physiological saline as necessary.
It was extracted (milking) in the form of sodium pertechnetate ^99m Tc (half-life 6.03 hours) as a daughter nuclide.

This take-out device, i.e., ⁹⁹ Mo- ^99m Tc generator, is constructed as shown in FIG. In FIG. 2, 1 is a ⁹⁹ Mo- ^99m Tc column, 2 is a physiological saline solution, 3 is a collecting vial, 4 is an elution needle, and 5 is an elution valve. Although not shown, the column 1, the vial 3 and the like where radioactive material is present are shielded with a lead container or the like to prevent leakage of radiation.

When milking, the elution injection needle 4 is inserted into the collecting vial 3 having a negative pressure inside, and the elution valve 5 is inserted.
When opened, physiological saline 2 passes through ⁹⁹ Mo- ^99m Tc column 1,
The produced ^99m Tc is eluted and enters the collecting vial 3.

By the way, ⁹⁹ as a parent nuclide adsorbed on column 1
Mo has a decreasing activity every moment along its half-life decay curve. In addition, the amount of radioactivity of ^99m Tc produced there and reaching the transient equilibrium also decreases. Therefore, when and how much ^99m Tc can be collected is based on the test date and time of the ⁹⁹ Mo- ^99m Tc generator shipped from the manufacturer and the test radioactivity amount at that time. Furthermore, after milking, ^99m Tc is generated along the predetermined generation curve,
The transient equilibrium is reached in 3 hours, and the ^99m Tc at this time is about 86% of ⁹⁹ Mo at this time.

The relationship between them is shown in FIG. Where the transient equilibrium of ^99m T
The radioactivity A _T of c is given by A _T = 0.86A _M (1). A _M is the radioactivity of ⁹⁹ Mo at that time,
_Assuming that the radioactivity of ⁹⁹ Mo at the time of verification is A _MO and the elapsed time is t, A _M = A _MO · e ^-0.0104t (2). In addition, the radioactivity A of ^99m Tc during production after milking
_T is given by _AT = 0.86A _MM · (1.0995) × (e ^-0.0104t −e ^-0.1149t … (3), where A _MM is ⁹⁹ M during milking.
It is the radioactivity of o and is calculated by the equation (2).

(Problems to be solved by the invention) However, in the past, in order to know the change with time of ^99m Tc, the time to reach the transient equilibrium after milking, or how much radioactivity was obtained at what time, an attenuation table was used. Very rough work has been done such as obtaining rough numerical values from the above or deriving them from the theoretical formula by calculation. In addition, the time of milking must be remembered, so it is easy to make a mistake, and if it is wrong, there is a risk that it will greatly hinder the inspection plan.

The present invention solves the above-mentioned problems of the prior art by using ^99m Tc
Accurately and easily check the radioactivity amount at any time and the ^99m Tc generation state after milking as necessary, simply by inputting the date and time of ⁹⁹ Mo certification in the generator, the radioactivity amount at that time, and the milking information when milking. The object is to provide a readable ^99m Tc generation / attenuation display device.

(Means for Solving the Problems) To achieve the above object, ^99m Tc generator attenuation display device of the present invention, the ^99m Tc generator, which is the parent nuclide of ^99m Tc ⁹⁹ Mo test date and test radioactivity level, Also, when milking, the means for inputting the milking information, the activity amount of ⁹⁹ Mo that decays with time from the entered test date and time and the activity amount of the assay, and the transient equilibrium based on the activity amount of the decaying ⁹⁹ Mo. Based on the radioactivity amount of ^99m Tc that reached the ^{maximum and} the radioactivity amount of ⁹⁹ Mo when milking, it is generated with the passage of time from the time of milking.
A means for calculating the radioactivity amount of ^99m Tc according to a pre-stored program, a storage means for storing the calculation result and updating the contents occasionally, and a calculation result is read out from the storage means as necessary. , A first display means for displaying, and a second for displaying ^99m Tc production rate after milking
Display means.

(Operation) According to this configuration, the time point and the radioactivity at the time point are constantly calculated with the passage of time from the test date and time, and can be displayed as necessary. Also, after milking
^{The 99m} Tc generation rate is always displayed, and it is possible to accurately read whether the transient equilibrium is reached or how many hours it will take to reach it.

(Example) Hereinafter, an example will be described in detail with reference to the drawings. FIG. 1 shows the appearance of an embodiment of the present invention. 11 is
^{A 99m} Tc generation / attenuation display device main body, 12 is a key operation unit, and is composed of, for example, the key arrangement shown in FIG. In addition to the ^99m Tc generation / attenuation display device, this device is equipped with Ci, Bq, and r
Since it has a unit conversion function of ad and Gy, rem and Sv, R and C / kg, a function to display the half-life of the nuclide by inputting the atomic number, an ordinary calculator function, a calendar and clock function, etc. , Keys are provided for operating those functions. ^Reference numeral 13 denotes a liquid crystal display unit, which displays the amount of radioactivity of ^{99 m} Tc at any time, as needed. 14 is an LED display unit, which displays the current ^99m Tc generation state by lighting the LED after milking.

FIG. 5 shows the hardware of this embodiment.
Is a microcomputer (hereinafter referred to as CPU), which performs the main operations and interacts with memory and external interfaces. 16 generates the system clock and CP
Oscillator supplied to U15, 17 is a counter IC that divides the system clock and gives a 37.5 Hz interrupt signal to the CPU 15, 1
8 is a read-only memory in which a required program is stored, 19 is a readable / writable memory that stores the calculation result of the CPU 15, and updates the contents momentarily, 20 is a clock and calendar IC, 21, 22, 23 is an interface of the liquid crystal display unit 13, the key operation unit 12 and the LED display unit 14, 24 is a system bus, 25 is a backup battery, which operates the clock and calendar even when the power is off, and is stored in the memory. Save the saved content.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, if the item to be displayed is not a radioactivity amount (calculated every minute) display, that is, in the case of unit conversion or general calculation, that display is performed.

When displaying the radioactivity, calculate the elapsed time t up to the current time based on the test date and time and the test radioactivity of ⁹⁹ Mo, which is the parent nuclide of ^{99 m} Tc, which was input in advance by the key operation unit. In addition, the variables stored in advance are read out, and the radioactivity amount is calculated by the equation (2). here,
The calculation formula of radioactivity varies depending on whether or not ^99m Tc is being generated after milking. That is, in the case of the transient equilibrium state before milking, the equation (1) is used as shown in FIG. On the other hand, if it is after milking, the elapsed time t from the start of milking is calculated, and the elapsed time is 23
If the time is exceeded, the transient equilibrium state is entered, so the milking flag is turned off, and the calculation is performed according to equation (1). If the elapsed time is less than 23 hours, equation (3) is applied. Then, based on the calculation result, the corresponding LED of the LED display unit 14 is turned on and the percentage of the transient equilibrium is displayed.
Further, the radioactivity is displayed on the liquid crystal display unit 13 as a numerical value.

Next, an example of a specific operation method is shown.

(A) When the ^99m Tc generator is received, enter the ⁹⁹ Mo certification date and time and the certification activity. For example, certification date: 88
December 31st, noon, when the radioactivity is 200mCi, when the PRESET key is turned on, The display looks like this, and enter the date and time.

After entering the date and time, The display will change to, and enter the amount of radioactivity. After inputting, press the ENT key.

Then, the following ^99m Tc attenuation display starts.

(B) For milking operation, for example, when milking on January 1, when the MILKING key is turned on, The current date and time are displayed.
After checking, press the ENT key.

(C) To find out when equilibrium is reached, use Time
When the key is turned on, The display looks like. After that, press the CLEAR key or 3
The display will change to the original display after 0 seconds.

(D) If you want to know the activity at a certain time, for example, if the activity at 15:00 on January 2nd, press the Act key and enter the date and time. The display looks like. After that, press the CLEAR key or the display will change to the original display after 30 seconds.

(Effects of the Invention) As described above, according to the present invention, (1) the temporal change of ^99m Tc can be known at any time.

(2) ^99m Tc generation rate after milking is always displayed, and the time when transient equilibrium is reached can be visually observed.

(3) It is possible to know at what time and how much radioactivity can be obtained.

(4) Moreover, the operation is only required to enter the test date and time of the ^99m Tc generator, the test radioactivity, and the milking key and press the milking key to input the information. After that, it is automatically calculated, and the simple operation key is used. You can display the exact amount of radioactivity just by pressing.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outer appearance of an embodiment of the present invention, and FIG.
Figure is a schematic diagram of ^99m Tc generator. Figure 3 is ⁹⁹ Mo.
Showing the relationship between the disintegration curve and the generation curve of ^99m Tc, FIG. 4 is a view showing the key operation part, FIG. 5 is a view showing the hardware of the same embodiment, and FIG. 6 is a view showing the same embodiment. It is a flow chart which shows operation. 11… ^99m Tc generation / attenuation display device body, 12… Key operation part, 1
3 ... Liquid crystal display, 14 ... LED display, 15 ... CPU, 18 ... Program memory, 19 ... Work memory, 20 ... Clock / calendar
IC, 21, 22, 23 ... Interface.

Claims (1)

[Claims] 1. A means for inputting the test date and time and the test radioactivity of ⁹⁹ Mo, which is the parent nuclide of ^99m Tc, and the milking information when milking, in the ^99m Tc generator, and the entered test time and test radiation. Based on the activity of ⁹⁹ Mo that decays over time from the activity, the activity of ^{99 m} Tc that has reached a transient equilibrium based on the activity of ⁹⁹ Mo that decays, and the activity of ⁹⁹ Mo during milking when milking. And the means for calculating the radioactivity amount of ^99m Tc generated with the passage of time from the time of milking according to a pre-stored program, and the storage means for storing the calculation result and updating the contents moment by moment. read the operation result as needed from the storage means, first display means for displaying a second display means for displaying a ^99m Tc generator rate after the milking, from ^99m Tc generator attenuation display device comprising Rukoto.