dcmodify(1)                       OFFIS DCMTK                      dcmodify(1)

NAME
       dcmodify - Modify DICOM files


SYNOPSIS
       dcmodify [options] dcmfile-in...

DESCRIPTION
       dcmodify  is  a  tool that allows one to modify, insert and delete tags
       and items in DICOM files. Sequences and tags with a value  multiplicity
       > 1 are also supported. Metaheader information and the tag's VR can not
       be  modified  directly  by  dcmodify  at  this time. In addition to tag
       modifications, dcmodify makes available some input  options  -  forcing
       dcmodify  to  handle its input files as the user specifies - and output
       options to control the output format of the resulting files.

       In case multiple modifications have to be performed, dcmodify does  the
       modifications  in  the  same  order as they appear on the command line.
       Please note that dcmodify does not check whether a given value  matches
       its value representation (VR). Usually, an error message is printed but
       generally the user should take care of the right VR usage.

       If dcmodify doesn't know the tag it should insert, then the tag's VR is
       set  to  UN  and  the  value provided on command line is interpreted as
       being a series of hexadecimal  numbers  (like  they  are  provided  for
       VR=OB).  Please  insert  these  tags  into the dictionary to avoid this
       behavior. Also, specifying the -iun option, it  is  possible  to  force
       dcmodify  to  leave  UN values untouched. Using option -u lets dcmodify
       saving all VR=UN attributes as OB.

       dcmodify is able to work with so-called tag paths  to  access  tags  in
       sequences. The (pseudo-formalized) syntax is

       {sequence[item-no].}*element

       where  'sequence'  is  a  sequence tag like (0008,1111) or a dictionary
       name for a tag. 'item-no' describes the  item  number  to  be  accessed
       (counting  from  zero).  'element' defines the target tag to work on. A
       tag can either be specified directly  as  (0010,0010)  or  through  the
       corresponding  dictionary  name 'PatientName'. The '*' denotes that you
       can repeat sequence statements to access deeper levels in  DICOM  files
       (see  EXAMPLES  section).  For 'item-no', also a wildcard character '*'
       can be used selecting all items in surrounding  sequence  (see  section
       WILDCARDS below).

       When  inserting  tag  paths  consisting  of  multiple nodes (i.e. not a
       single element) using the -i option, any missing path elements  (items,
       sequences, leaf elements) are inserted automatically when missing. That
       does  not  work  for  item wildcards: When no single item exists in the
       surrounding sequence dcmodify of course can't decide,  how  many  items
       should  be  generated.  However, if specifying an item number like '5',
       all 6  items  (counted  from  zero)  can  be  (and  are)  automatically
       generated  in insert mode. If already 2 items would exist, the rest (4)
       would be inserted.

       dcmodify does not work on directories, i.e. the parameter dcmfile-in...
       must not include directory names.

       Please note that there are some issues concerning the  modification  of
       private tags (see PRIVATE TAGS section) and for changing UIDs (CHANGING
       UIDs section).

PARAMETERS
       dcmfile-in  DICOM input filename(s) to be modified ("-" for stdin/stdout)

OPTIONS
   general options
         -h    --help
                 print this help text and exit

               --version
                 print version information and exit

               --arguments
                 print expanded command line arguments

         -q    --quiet
                 quiet mode, print no warnings and errors

         -v    --verbose
                 verbose mode, print processing details

         -d    --debug
                 debug mode, print debug information

         -ll   --log-level  [l]evel: string constant
                 (fatal, error, warn, info, debug, trace)
                 use level l for the logger

         -lc   --log-config  [f]ilename: string
                 use config file f for the logger

   input options
       input file format:

         +f    --read-file
                 read file format or data set (default)

         +fo   --read-file-only
                 read file format only

         -f    --read-dataset
                 read data set without file meta information

         +fc   --create-file
                 create file format if file does not exist

       input transfer syntax:

         -t=   --read-xfer-auto
                 use TS recognition (default)

         -td   --read-xfer-detect
                 ignore TS specified in the file meta header

         -te   --read-xfer-little
                 read with explicit VR little endian TS

         -tb   --read-xfer-big
                 read with explicit VR big endian TS

         -ti   --read-xfer-implicit
                 read with implicit VR little endian TS

       parsing of odd-length attributes:

         +ao   --accept-odd-length
                 accept odd length attributes (default)

         +ae   --assume-even-length
                 assume real length is one byte larger

       automatic data correction:

         +dc   --enable-correction
                 enable automatic data correction (default)

         -dc   --disable-correction
                 disable automatic data correction

       bitstream format of deflated input:

         +bd   --bitstream-deflated
                 expect deflated bitstream (default)

         +bz   --bitstream-zlib
                 expect deflated zlib bitstream

   processing options
       backup input files:

               --backup
                 backup files before modifying (default)

         -nb   --no-backup
                 don't backup files (DANGEROUS)

       insert mode:

         -i    --insert  "[t]ag-path=[v]alue"
                 insert (or overwrite) path at position t with value v

         -if   --insert-from-file  "[t]ag-path=[f]ilename"
                 insert (or overwrite) path at position t with value from file f

         -nrc  --no-reserv-check
                 do not check private reservations

       modify mode:

         -m    --modify  "[t]ag-path=[v]alue"
                 modify tag at position t to value v

         -mf   --modify-from-file  "[t]ag-path=[f]ilename"
                 modify tag at position t to value from file f

         -ma   --modify-all  "[t]ag=[v]alue"
                 modify ALL matching tags t in file to value v

       erase mode:

         -e    --erase  "[t]ag-path"
                 erase tag/item at position t

         -ea   --erase-all  "[t]ag"
                 erase ALL matching tags t in file

         -ep   --erase-private
                 erase ALL private data from file

       unique identifier:

         -gst  --gen-stud-uid
                 generate new Study Instance UID

         -gse  --gen-ser-uid
                 generate new Series Instance UID

         -gin  --gen-inst-uid
                 generate new SOP Instance UID

         -nmu  --no-meta-uid
                 do not update metaheader UIDs if related
                 UIDs in the dataset are modified

       error handling:

         -ie   --ignore-errors
                 continue with file, if modify error occurs

         -imt  --ignore-missing-tags
                 treat 'tag not found' as success
                 when modifying or erasing in files

         -iun  --ignore-un-values
                 do not try writing any values to elements
                 having a VR of UN

   output options
       output file format:

         +F    --write-file
                 write file format (default)

         -F    --write-dataset
                 write data set without file meta information

       output transfer syntax:

         +t=   --write-xfer-same
                 write with same TS as input (default)

         +te   --write-xfer-little
                 write with explicit VR little endian TS

         +tb   --write-xfer-big
                 write with explicit VR big endian TS

         +ti   --write-xfer-implicit
                 write with implicit VR little endian TS

       post-1993 value representations:

         +u    --enable-new-vr
                 enable support for new VRs (UN/UT) (default)

         -u    --disable-new-vr
                 disable support for new VRs, convert to OB

       group length encoding:

         +g=   --group-length-recalc
                 recalculate group lengths if present (default)

         +g    --group-length-create
                 always write with group length elements

         -g    --group-length-remove
                 always write without group length elements

       length encoding in sequences and items:

         +le   --length-explicit
                 write with explicit lengths (default)

         -le   --length-undefined
                 write with undefined lengths

       data set trailing padding (not with --write-dataset):

         -p=   --padding-retain
                 do not change padding (default if not --write-dataset)

         -p    --padding-off
                 no padding (implicit if --write-dataset)

         +p    --padding-create  [f]ile-pad [i]tem-pad: integer
                 align file on multiple of f bytes and items on
                 multiple of i bytes

PRIVATE TAGS
       There  are  some  issues you have to consider when working with private
       tags. However, the insertion  or  modification  of  a  reservation  tag
       (gggg,00xx) should always work.

   Insertions
       If you wish to insert a private tag (not a reservation with gggg,00xx),
       be   sure,   that   you've   listed   it   in   your   dictionary  (see
       <docdir>/datadict.txt for details). If it's not listed,  dcmodify  will
       insert  it with VR=UN. Also, for some cases insertion may even fail for
       some values.

       If you've got your private tag in  the  dictionary,  dcmodify  acts  as
       follows:  When  it  finds a reservation in the tag's enclosing dataset,
       whose private creator matches, insertion is done with the VR  found  in
       the  dictionary and the value given on command line. But if the private
       creator doesn't match or none is set,  dcmodify  will  return  with  an
       error.  If  a  private  tag  should  be  inserted  regardless whether a
       reservation does not exist, the option -nrc can  be  used,  forcing  an
       insertion.  However,  the  VR  is  set to UN then, because the tag then
       cannot be found in the dictionary.

       See description above how inserting values into elements  with  unknown
       VR are handled.

   Modifications
       If you modify a private tags value, dcmodify won't check its VR against
       the  dictionary.  So  please be careful to enter only values that match
       the tag's VR.

       If you wish to change a private tags value and  VR,  because  you  just
       added  this tag to your dictionary, you can delete it with dcmodify and
       re-insert it. Then dcmodify uses your dictionary entry to determine the
       right VR (also see subsection insertions).

       Also, see description above how inserting  values  into  elements  with
       unknown VR are handled.

   Deletions
       When  you use dcmodify to delete a private reservation tag, please note
       that dcmodify  won't  touch  the  private  tags  that  are  under  this
       reservation.  The  user  is  forced  to  handle the consistency between
       reservations and their associated private tags.

       For the deletion of private non-reservation tags there are  no  special
       issues.

CHANGING UIDS
       dcmodify  will  automatically correct 'Media Storage SOP Class UID' and
       'Media Storage SOP Instance UID' in the metaheader, if you make changes
       to the related tags in the dataset ('SOP Class UID' and  'SOP  Instance
       UID')  via insert or modify mode options. You can disable this behavior
       by using the -nmu option.

       If you generate new UID's with -gst,  -gse  or  -gin,  this  will  only
       affect  the UID you chose to generate. So if you use -gst to generate a
       new 'Study Instance UID', then 'Series Instance UID' and 'SOP  Instance
       UID'  will  not be affected! This gives you the possibility to generate
       each value separately. Normally, you would also modify the 'underlying'
       UIDs. As a disadvantage of this flexibility, the user  has  to  assure,
       that when creating 'new' DICOM files with new UIDs with dcmodify, other
       UIDs have to be updated by the user as necessary.

       When  choosing  the  -gin  option,  the  related metaheader tag ('Media
       Storage SOP Instance UID')  is  updated  automatically.  This  behavior
       cannot be disabled.

       When  working  on multiple input files, dcmodify processes each file in
       isolated fashion, i.e. it will generate UIDs for each single file.  For
       example,  when  using the -gst option, dcmodify will insert a different
       Study Instance UID into each file instead of generating  a  single  one
       and writing it to each file that is being processed.

CREATING NEW FILES
       Option --create-file lets dcmodify create a file if it does not already
       exist  on  disk. This can be used in order to create files from scratch
       by performing consecutive insertions with options like  --insert.  This
       might  especially become handy when creating query files for tools like
       findscu or movescu. In case  no  specific  output  transfer  syntax  is
       defined,  dcmodify  chooses  Little  Endian  Explicit  Uncompressed for
       output. Files that are newly created are always written as  DICOM  file
       format,  i.e.  option  --write-dataset  is  not permitted together with
       --create. This way, at least the metaheader is written and no file with
       zero byte length is created in a case where no insertions are performed
       in the dcmodify call.

ELEMENT VALUES FROM FILE
       In order to read the element value from a file instead of specifying it
       on the command line, option -mf and -if can be used. Please  note  that
       for  OW  elements, the data is expected to be little endian ordered and
       will be swapped if necessary. The file size should always  be  an  even
       number of bytes, i.e. no automatic padding is performed.

WILDCARDS
       dcmodify  also  permits  the usage of a wildcard character '*' for item
       numbers  in  path  expressions,   e.g.   'ContentSequence[*].CodeValue'
       selects   all   'Code   Value'   attributes   in   all   items  of  the
       ContentSequence. Using a wildcard is possible for all basic operations,
       i.e. modifying -m, inserting -i and -e options which makes it, together
       with the automatic creation of intermediate path nodes a powerful  tool
       for construction and processing complex datasets.

       The  options -ma and -ea for modifying or deleting all occurrences of a
       DICOM element based on its tag do not accept  any  wildcards  but  only
       work on single elements (i.e. a single dictionary name or tag key).

EXAMPLES
       -i   --insert:
              dcmodify -i "(0010,0010)=A Name" file.dcm
              Inserts the PatientName tag into 'file.dcm' at 1st level.
              If tag already exists, -i will overwrite it!  If you want to
              insert an element with value multiplicity > 1 (e.g. 4) you
              can do this with: dcmodify -i "(0018,1310)=1\2\3\4"

              dcmodify -i "(0008,1111)[0].PatientName=Another Name" *.dcm
              Inserts PatientName tag into the first item of sequence
              (0008,1111).  Note that the use of wildcards for files is
              possible.  You can specify longer tag paths, too (e.g.
              "(0008,1111)[0].(0008,1111)[1].(0010,0010)=A Third One").
              If any part of the path, e.g. the sequence or the item "0"
              does not exist, it is automatically inserted by dcmodify.

              dcmodify -i "(0008,1111)[*].PatientName=Another Name" *.dcm
              Inserts PatientName tag into _every_ item of sequence
              (0008,1111).  Note that the use of wildcards for files is
              possible.  You can specify longer tag paths, too (e.g.
              "(0008,1111)[*].(0008,1111)[*].(0010,0010)=A Third One").

       -if  --insert-from-file:
              dcmodify -if "PixelData=pixel.raw" file.dcm
              Inserts the content of file 'pixel.raw' into the PixelData element
              of 'file.dcm'.  The contents of the file will be read as is.
              OW data is expected to be little endian ordered and will be
              swapped if necessary.  No checks will be made to ensure that the
              amount of data is reasonable in terms of other attributes such as
              Rows or Columns.

       -m   --modify:
              dcmodify -m "(0010,0010)=A Name" file.dcm
              Changes tag (0010,0010) on 1st level to "A Name".

              This option also permits longer tag paths as demonstrated above
              for -i. If the leaf element or any intermediate part of the path
              does not exist, it is not inserted as it would be if using the
              '-i' option.

              dcmodify -m "(0010,0010)=A Name" -imt file.dcm
              Changes tag (0010,0010) on 1st level to "A Name". Due to the given
              option '-imt', success is returned instead of "tag not found", if
              the element/item (or any intermediate node in a longer path) does
              not exist.

              Note that for the '-m' option the last node in the path must be a
              leaf element, i.e. not a sequence or an item.

       -mf  --modify-from-file:
              dcmodify -mf "PixelData=pixel.raw" file.dcm
              Does the same as -if in case there was already a PixelData element
              in 'file.dcm'.  Otherwise nothing is changed.

       -ma  --modify-all:
              dcmodify -ma "(0010,0010)=New Name" file.dcm
              Does the same as -m but works on all matching tags found in
              'file.dcm'.  Therefore, it searches the whole dataset including
              sequences for tag (0010,0010) and changes them to "New Name"

       -e   --erase:
              dcmodify -e "(0010,0010)" *.dcm
              Erases tag (0010,0010) in all *.dcm files at 1st level.

              This option also allows longer tag paths as demonstrated
              above for -i.

              dcmodify -e "(0010,0010)" -imt *.dcm
              Erases tag (0010,0010) in all *.dcm files at 1st level. Due to the
              given option '-imt', success is returned instead of "tag not
              found", if the element/item (or any intermediate node in a longer
              path) does not exist.

       -ea  --erase-all:
              dcmodify -ea "(0010,0010)" *.dcm
              Same as -e, but also searches in sequences and items.

       -ep  --erase-private:
              dcmodify -ep *.dcm
              Deletes all private tags (i.e. tags having an odd group number)
              from all files matching *.dcm in the current directory.

       -gst --gen-stud-uid:
              dcmodify -gst file.dcm
              This generates a new value for the StudyInstanceUID (0020,000d).
              Other UIDs are not modified!

       -gse --gen-ser-uid:
              dcmodify -gse file.dcm
              This generates a new value for the SeriesInstanceUID (0020,000e).
              Other UIDs are not modified!

       -gin --gen-inst-uid:
              dcmodify -gin file.dcm
              This command generates a new value for the SOPInstanceUID
              (0008,0018).  The corresponding MediaStorageSOPInstanceUID
              (0002,0003) is adjusted to the new value automatically.
              Please note that it's not possible to avoid this metaheader
              update via the -nmu option.

       -nmu --no-meta-uid:
              dcmodify -m "SOPInstanceUID=[UID]" -nmu *.dcm
              This will modify the SOPInstanceUID to the given [UID], but -nmu
              avoids, that dcmodify adjusts the MediaStorageSOPInstanceUID in
              the metaheader, too.

ERROR HANDLING
       dcmodify  tries  executing each modify operation given on command line:
       If one returns an error, the others are being performed anyway. However
       in case of any error, the  modified  file  is  not  saved,  unless  the
       --ignore-errors  option  is  specified.  If  that  option  is selected,
       dcmodify also continues modifying further files  specified  on  command
       line;   otherwise   dcmodify  exits  after  the  first  file  that  had
       modification errors.

       If the --ignore-missing-tags option is enabled,  any  modify  or  erase
       operations (i.e. not --insert) that fails because of a non-existing tag
       is  treated  as being successful. That does make sense if someone wants
       to be sure that specific tags are not present in the file or that -  if
       they exist - that they are set to a specific value.

LOGGING
       The  level  of  logging  output  of  the various command line tools and
       underlying libraries can be specified by the  user.  By  default,  only
       errors  and  warnings  are  written to the standard error stream. Using
       option --verbose also informational messages  like  processing  details
       are  reported.  Option  --debug  can be used to get more details on the
       internal activity, e.g. for debugging purposes.  Other  logging  levels
       can  be  selected  using option --log-level. In --quiet mode only fatal
       errors are reported. In such very severe error events, the  application
       will  usually  terminate.  For  more  details  on the different logging
       levels, see documentation of module 'oflog'.

       In case the logging output should be written to file  (optionally  with
       logfile  rotation),  to syslog (Unix) or the event log (Windows) option
       --log-config can be used.  This  configuration  file  also  allows  for
       directing  only  certain messages to a particular output stream and for
       filtering certain messages based on the  module  or  application  where
       they  are  generated.  An  example  configuration  file  is provided in
       <etcdir>/logger.cfg.

COMMAND LINE
       All command line tools  use  the  following  notation  for  parameters:
       square  brackets  enclose  optional  values  (0-1), three trailing dots
       indicate that multiple values are allowed (1-n), a combination of  both
       means 0 to n values.

       Command line options are distinguished from parameters by a leading '+'
       or  '-' sign, respectively. Usually, order and position of command line
       options are arbitrary (i.e. they  can  appear  anywhere).  However,  if
       options  are  mutually exclusive the rightmost appearance is used. This
       behavior conforms to the  standard  evaluation  rules  of  common  Unix
       shells.

       In  addition,  one  or more command files can be specified using an '@'
       sign as a prefix to the filename (e.g. @command.txt).  Such  a  command
       argument  is  replaced  by  the  content of the corresponding text file
       (multiple whitespaces are treated as a  single  separator  unless  they
       appear  between  two  quotation marks) prior to any further evaluation.
       Please note that a command file cannot contain  another  command  file.
       This  simple  but  effective  approach  allows  one to summarize common
       combinations of options/parameters and  avoids  longish  and  confusing
       command lines (an example is provided in file <datadir>/dumppat.txt).

ENVIRONMENT
       The  dcmodify  utility  will  attempt  to  load DICOM data dictionaries
       specified in the DCMDICTPATH environment variable. By default, i.e.  if
       the   DCMDICTPATH   environment   variable   is   not   set,  the  file
       <datadir>/dicom.dic will be loaded unless the dictionary is built  into
       the application (default for Windows).

       The   default   behavior   should  be  preferred  and  the  DCMDICTPATH
       environment variable only used when alternative data  dictionaries  are
       required.  The  DCMDICTPATH environment variable has the same format as
       the Unix shell PATH variable in that a colon (':')  separates  entries.
       On  Windows systems, a semicolon (';') is used as a separator. The data
       dictionary code will  attempt  to  load  each  file  specified  in  the
       DCMDICTPATH  environment variable. It is an error if no data dictionary
       can be loaded.

COPYRIGHT
       Copyright (C) 2003-2025 by OFFIS e.V., Escherweg  2,  26121  Oldenburg,
       Germany.

Version 3.7.0                   Mon Dec 15 2025                    dcmodify(1)
