请给出基于vtk、simpleITK、和pyqt5库实现读取nii.gz医学影像数据，并且能够3D影像数据展示的python代码

以下是可以用于读取nii.gz医学图像数据并进行3D数据展示的Python代码。需要安装vtk、simpleITK和pyqt5库。

import vtk
import SimpleITK as sitk
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class vtkWindow(QMainWindow):
    def __init__(self, parent=None):
        super(vtkWindow, self).__init__(parent)

        self.renderer = vtk.vtkRenderer()
        self.renWin = vtk.vtkRenderWindow()
        self.renWin.AddRenderer(self.renderer)
        self.iren = vtk.vtkRenderWindowInteractor()
        self.iren.SetRenderWindow(self.renWin)

        self.viewWidget = QVTKRenderWindowInteractor()
        self.vtkLayout = QHBoxLayout(self.viewWidget)
        self.vtkLayout.addWidget(self.iren)
        self.setCentralWidget(self.viewWidget)

    def show(self, *args, **kwargs):
        super(vtkWindow, self).show(*args, **kwargs)
        self.iren.Initialize()
        self.renWin.Render()

    def set_image(self, sitk_image):
        image_data = sitk.GetArrayFromImage(sitk_image)
        z, y, x = image_data.shape
        imageData = vtk.vtkImageData()
        imageData.SetDimensions(x, y, z)
        imageData.AllocateScalars(vtk.VTK_UNSIGNED_CHAR, 1)

        for i in range(z):
            for j in range(y):
                for k in range(x):
                    imageData.SetScalarComponentFromDouble(k, j, i, 0, image_data[i][j][k])

        image_actor = vtk.vtkImageActor()
        image_actor.SetInputData(imageData)

        self.renderer.AddActor(image_actor)
        self.renderer.ResetCamera()
        self.renWin.Render()

if __name__ == "__main__":
    app = QApplication([])
    vtk_win = vtkWindow()

    itk_image = sitk.ReadImage("path/to/nifti.gz")
    vtk_win.set_image(itk_image)

    vtk_win.show()
    app.exec_()

这里主要用到了`vtkWindow`类，该类负责创建VTK窗口，并同时与pyqt5窗口进行交互。`set_image`函数用于将simpleITK图像导入到VTK窗口中进行显示，主要调用了VTK中的`vtkImageActor`类将simpleITK中的图像转换为VTK图像进行显示。```vtkWindow```继承QMainWindow可以在其他需要显示场景窗口的位置嵌入vtk进去。