// Find the "Pixel Data" tag
aTag := ImageEnMView1.MIO.Params[0].DICOM_FindTag( $7FE0, $0010 );
if assigned( aTag ) then
  With aTag^ do...

function TIOParamsHelper.DICOM_FindTag(Group: Word; Element: Word): PIEDicomTag;
  {}
  procedure _ParseTags(tags: TIEDicomTags);
  var
    i, j: integer;
    tag: PIEDicomTag;
  begin
    for i := 0 to tags.Count - 1 do
    begin
      // GET DATA
      tag := tags.GetTag(i);
      if ( tag^.Group = Group ) and ( tag^.Element = Element ) then
      begin
        Result := tag;
        Exit;
      end;

      // PARSE ANY CHILDREN
      if assigned( tag.Children ) then
      begin
        // tag.Children is a TObjectList object where each item is a TIEDicomTags object
        for j := 0 to tag.Children.Count - 1 do
        begin
          _ParseTags( tag.Children[j] as TIEDicomTags );

          // Found tag?
          if Result <> nil then
            Exit;
        end;
      end;
    end;
  end;
  {}
begin
  result := nil;
  _ParseTags( DICOM_Tags );
end;

procedure TMainForm.Button1Click(Sender: TObject);
var
  atag: PIEDicomTag;
begin
  atag := MainForm.ImageEnMView1.MIO.Params[0].DICOM_FindTag($7FE0,$0010);
  if atag = nil then
    raise Exception.create( 'Invalid Tag' );
  // Do something with atag^.Data
end;

 atag: PIEDicomTag;
  doseRT:TIEDicomTags;

procedure TForm3.ReadRTStruct(RTtags: TIEDicomTags);
 var
  RTtag: PIEDicomTag;

  i:Integer;
 begin
  for i := 0 to RTtags.Count - 1 do
  begin
   if (RTtag^.Group=$7FE0)and(RTtag^.Element=$0010) then
   begin
  //  atag:=RTtag;
    doseRT:= RTtags;
   end;
  end;
 end;

//...............

//.........
 procedure TForm3.ReadRTdose(tags: TIEDicomTags);
 var
 RTtag: PIEDicomTag;

  i:Integer;
 begin
  for i := 0 to tags.Count - 1 do
  begin
   redt1.Lines.Add(tags.GetTagString(i))

  end;
 end;

//.................

function DICOM_FindTag(tags: TIEDicomTags; Group: Word; Element: Word): PIEDicomTag;
  {}
  procedure _ParseTags(tags: TIEDicomTags);
  var
    i, j: integer;
    tag: PIEDicomTag;
  begin
    for i := 0 to tags.Count - 1 do
    begin
      // GET DATA
      tag := tags.GetTag(i);
      if ( tag^.Group = Group ) and ( tag^.Element = Element ) then
      begin
        Result := tag;
        Exit;
      end;

      // PARSE ANY CHILDREN
      if assigned( tag.Children ) then
      begin
        // tag.Children is a TObjectList object where each item is a TIEDicomTags object
        for j := 0 to tag.Children.Count - 1 do
        begin
          _ParseTags( tag.Children[j] as TIEDicomTags );

          // Found tag?
          if Result <> nil then
            Exit;
        end;
      end;
    end;
  end;
  {}
begin
  result := nil;
  _ParseTags( DICOM_Tags );
end;

(0002,0000) File Meta Information Group Length (UL) : "26"
(0002,0010) Transfer Syntax UID (UI) : "1.2.840.10008.1.2"
(0008,0005) Specific Character Set (CS) : "ISO_IR 100"
(0008,0012) Instance Creation Date (DA) : "20150310"
(0008,0013) Instance Creation Time (TM) : "154423.0"
(0008,0016) SOP Class UID (UI) : "1.2.840.10008.5.1.4.1.1.481.2"
(0008,0018) SOP Instance UID (UI) : "1.2.410.200018.1001.1.2.67324533.0.20150310154420719"
(0008,0020) Study Date (DA) : "20150308"
(0008,0030) Study Time (TM) : "115319.296000 "
(0008,0050) Accession Number (SH) : ""
(0008,0060) Modality (CS) : "RTDOSE"
(0008,0070) Manufacturer (LO) : "Seoul C&J "
(0008,0090) Referring Physician's Name (PN) : ""
(0008,1030) Study Description (LO) : "RT^RT_Pelvis (Adult)"
(0008,1090) Manufacturer's Model Name (LO) : "CorePLAN"
(0010,0010) Patient's Name (PN) : "GHORBANIAN^KAZEM"
(0010,0020) Patient ID (LO) : "790258"
(0010,0030) Patient's Birth Date (DA) : "19610308"
(0010,0040) Patient's Sex (CS) : "M "
(0018,0050) Slice Thickness (DS) : ""
(0020,000D) Study Instance UID (UI) : "1.3.12.2.1107.5.1.4.80126.30000015030508240482800000592"
(0020,000E) Series Instance UID (UI) : "1.2.410.200018.1001.1.2.67324533.0.20150310154420719"
(0020,0010) Study ID (SH) : "1 "
(0020,0011) Series Number (IS) : ""
(0020,0013) Instance Number (IS) : ""
(0020,0032) Image Position (Patient) (DS) : "250\410\-1593 "
(0020,0037) Image Orientation (Patient) (DS) : "-1\0\0\0\-1\0 "
(0028,0002) Samples per Pixel (US) : "1"
(0028,0004) Photometric Interpretation (CS) : "MONOCHROME2 "
(0028,0008) Number of Frames (IS) : "98"
(0028,0009) Frame Increment Pointer (AT) : "798724"
(0028,0010) Rows (US) : "70"
(0028,0011) Columns (US) : "101"
(0028,0030) Pixel Spacing (DS) : "5\5 "
(0028,0100) Bits Allocated (US) : "32"
(0028,0101) Bits Stored (US) : "32"
(0028,0102) High Bit (US) : "31"
(0028,0103) Pixel Representation (US) : "0"
(3004,0002) Dose Units (CS) : "GY"
(3004,0004) Dose Type (CS) : "PHYSICAL"
(3004,000A) Dose Summation Type (CS) : "PLAN"
(3004,000C) Grid Frame Offset Vector (DS) : "0\3.00003051757813\6...<SNIP>...5156 "
(3004,000E) Dose Grid Scaling (DS) : "1.e-007 "
(300C,0002) Referenced RT Plan Sequence (SQ) : ""
0:
   (0008,1150) Referenced SOP Class UID (UI) : "1.2.840.10008.5.1.4.1.1.481.5"
   (0008,1155) Referenced SOP Instance UID (UI) : "1.2.410.200018.1001.1.5.67324533.0.20150310154420719"
   (7FE0,0010) Pixel Data (OW) : ""