diff -urEb dcmtk-3.6.9.orig/CMake/GenerateDCMTKConfigure.cmake dcmtk-3.6.9/CMake/GenerateDCMTKConfigure.cmake
--- dcmtk-3.6.9.orig/CMake/GenerateDCMTKConfigure.cmake	2025-02-18 18:03:13.505405952 +0100
+++ dcmtk-3.6.9/CMake/GenerateDCMTKConfigure.cmake	2025-02-18 18:06:53.925278621 +0100
@@ -227,12 +227,15 @@
 
 # Check the sizes of various types
 include (CheckTypeSize)
+if (NOT CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
+  # This doesn't work for wasm, Orthanc defines the macros manually
 CHECK_TYPE_SIZE("double" SIZEOF_DOUBLE)
 CHECK_TYPE_SIZE("float" SIZEOF_FLOAT)
 CHECK_TYPE_SIZE("int" SIZEOF_INT)
 CHECK_TYPE_SIZE("long" SIZEOF_LONG)
 CHECK_TYPE_SIZE("short" SIZEOF_SHORT)
 CHECK_TYPE_SIZE("void*" SIZEOF_VOID_P)
+endif()
 
 # Check for include files, libraries, and functions
 include("${DCMTK_CMAKE_INCLUDE}CMake/dcmtkTryCompile.cmake")
diff -urEb dcmtk-3.6.9.orig/dcmdata/include/dcmtk/dcmdata/dcdict.h dcmtk-3.6.9/dcmdata/include/dcmtk/dcmdata/dcdict.h
--- dcmtk-3.6.9.orig/dcmdata/include/dcmtk/dcmdata/dcdict.h	2025-02-18 18:03:13.497406077 +0100
+++ dcmtk-3.6.9/dcmdata/include/dcmtk/dcmdata/dcdict.h	2025-02-18 18:06:53.925278621 +0100
@@ -163,6 +163,12 @@
     /// returns an iterator to the end of the repeating groups data dictionary
     DcmDictEntryListIterator repeatingEnd() { return repDict.end(); }
 
+    // Function by the Orthanc project to load a dictionary from a
+    // memory buffer, which is necessary in sandboxed
+    // environments. This is an adapted version of
+    // DcmDataDictionary::loadDictionary().
+    OFBool loadFromMemory(const std::string& content, OFBool errorIfAbsent = OFTrue);
+    
 private:
 
     /** private undefined assignment operator
diff -urEb dcmtk-3.6.9.orig/dcmdata/libsrc/dcdict.cc dcmtk-3.6.9/dcmdata/libsrc/dcdict.cc
--- dcmtk-3.6.9.orig/dcmdata/libsrc/dcdict.cc	2025-02-18 18:03:13.499406046 +0100
+++ dcmtk-3.6.9/dcmdata/libsrc/dcdict.cc	2025-02-18 18:06:53.926278608 +0100
@@ -904,3 +904,5 @@
   wrlock().clear();
   wrunlock();
 }
+
+#include "dcdict_orthanc.cc"
diff -urEb dcmtk-3.6.9.orig/dcmdata/libsrc/dcpxitem.cc dcmtk-3.6.9/dcmdata/libsrc/dcpxitem.cc
--- dcmtk-3.6.9.orig/dcmdata/libsrc/dcpxitem.cc	2025-02-18 18:03:13.497406077 +0100
+++ dcmtk-3.6.9/dcmdata/libsrc/dcpxitem.cc	2025-02-18 18:06:53.926278608 +0100
@@ -31,6 +31,8 @@
 #include "dcmtk/dcmdata/dcostrma.h"    /* for class DcmOutputStream */
 #include "dcmtk/dcmdata/dcwcache.h"    /* for class DcmWriteCache */
 
+#undef max
+#include "dcmtk/ofstd/oflimits.h"
 
 // ********************************
 
diff -urEb dcmtk-3.6.9.orig/dcmnet/libsrc/scu.cc dcmtk-3.6.9/dcmnet/libsrc/scu.cc
--- dcmtk-3.6.9.orig/dcmnet/libsrc/scu.cc	2025-02-18 18:03:13.525405640 +0100
+++ dcmtk-3.6.9/dcmnet/libsrc/scu.cc	2025-02-18 18:06:53.927278595 +0100
@@ -19,6 +19,11 @@
  *
  */
 
+#if defined(_WIN32)
+#  define __STDC_LIMIT_MACROS   // Get access to UINT16_MAX
+#  include <stdint.h>
+#endif
+
 #include "dcmtk/config/osconfig.h" /* make sure OS specific configuration is included first */
 
 #include "dcmtk/dcmdata/dcostrmf.h" /* for class DcmOutputFileStream */
diff -urEb dcmtk-3.6.9.orig/oficonv/include/dcmtk/oficonv/iconv.h dcmtk-3.6.9/oficonv/include/dcmtk/oficonv/iconv.h
--- dcmtk-3.6.9.orig/oficonv/include/dcmtk/oficonv/iconv.h	2025-02-18 18:03:13.510405874 +0100
+++ dcmtk-3.6.9/oficonv/include/dcmtk/oficonv/iconv.h	2025-02-18 18:06:53.927278595 +0100
@@ -55,7 +55,12 @@
 #endif
 
 struct __tag_iconv_t;
+
+#if defined(__LSB_VERSION__)
+typedef void *iconv_t;
+#else
 typedef struct __tag_iconv_t *iconv_t;
+#endif
 
 #ifndef OFICONV_CITRUS_WC_T_DEFINED
 #define OFICONV_CITRUS_WC_T_DEFINED
diff -urEb dcmtk-3.6.9.orig/oficonv/libsrc/citrus_csmapper.c dcmtk-3.6.9/oficonv/libsrc/citrus_csmapper.c
--- dcmtk-3.6.9.orig/oficonv/libsrc/citrus_csmapper.c	2025-02-18 18:03:13.510405874 +0100
+++ dcmtk-3.6.9/oficonv/libsrc/citrus_csmapper.c	2025-02-18 18:06:53.927278595 +0100
@@ -63,7 +63,8 @@
 
 #ifdef WITH_THREADS
 #ifdef HAVE_WINDOWS_H
-static SRWLOCK ma_lock = SRWLOCK_INIT;
+static int ma_lock_initialized = 0;
+static CRITICAL_SECTION ma_lock;
 #elif defined(HAVE_PTHREAD_H)
 static pthread_rwlock_t ma_lock = PTHREAD_RWLOCK_INITIALIZER;
 #endif
@@ -382,6 +383,14 @@
     char mapper_path[OFICONV_PATH_MAX];
     unsigned long norm;
     int ret;
+
+#if defined(WITH_THREADS) && defined(HAVE_WINDOWS_H)
+    if (ma_lock_initialized == 0) { /* Very minor risk of race condition here */
+      InitializeCriticalSection(&ma_lock);
+      ma_lock_initialized = 1;
+    }
+#endif
+
     norm = 0;
 
     getCSMapperPath(mapper_path, sizeof(mapper_path), NULL);
diff -urEb dcmtk-3.6.9.orig/oficonv/libsrc/citrus_iconv.c dcmtk-3.6.9/oficonv/libsrc/citrus_iconv.c
--- dcmtk-3.6.9.orig/oficonv/libsrc/citrus_iconv.c	2025-02-18 18:03:13.520405718 +0100
+++ dcmtk-3.6.9/oficonv/libsrc/citrus_iconv.c	2025-02-18 18:10:35.928614598 +0100
@@ -49,7 +49,15 @@
 #endif
 
 #include <limits.h>
+
+#if (_MSC_VER >= 1900)
 #include <stdbool.h>
+#else
+#define bool int
+#define false 0
+#define true 1
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -80,7 +88,8 @@
 
 #ifdef WITH_THREADS
 #ifdef HAVE_WINDOWS_H
-static SRWLOCK ci_lock = SRWLOCK_INIT;
+static int ci_lock_initialized = 0;
+static CRITICAL_SECTION ci_lock;
 #elif defined(HAVE_PTHREAD_H)
 static pthread_rwlock_t ci_lock = PTHREAD_RWLOCK_INITIALIZER;
 #endif
@@ -299,14 +308,24 @@
 _citrus_iconv_open(struct _citrus_iconv * * rcv,
     const char * src, const char * dst)
 {
-struct _citrus_iconv *cv = NULL;
+#ifdef HAVE_WINDOWS_H
+    char current_codepage[20];
+#endif
+
+    struct _citrus_iconv *cv = NULL;
     struct _citrus_iconv_shared *ci = NULL;
     char realdst[OFICONV_PATH_MAX], realsrc[OFICONV_PATH_MAX];
     int ret;
 
+#if defined(WITH_THREADS) && defined(HAVE_WINDOWS_H)
+    if (ci_lock_initialized == 0) { /* Very minor risk of race condition here */
+      InitializeCriticalSection(&ci_lock);
+      ci_lock_initialized = 1;
+    }
+#endif
+
     init_cache();
 #ifdef HAVE_WINDOWS_H
-    char current_codepage[20];
     snprintf(current_codepage, sizeof(current_codepage), "%lu", (unsigned long) GetConsoleOutputCP());
 #endif
 
diff -urEb dcmtk-3.6.9.orig/oficonv/libsrc/citrus_lock.h dcmtk-3.6.9/oficonv/libsrc/citrus_lock.h
--- dcmtk-3.6.9.orig/oficonv/libsrc/citrus_lock.h	2025-02-18 18:03:13.518405749 +0100
+++ dcmtk-3.6.9/oficonv/libsrc/citrus_lock.h	2025-02-18 18:06:53.927278595 +0100
@@ -31,11 +31,11 @@
 
 #ifdef WITH_THREADS
 
-#ifdef HAVE_WINDOWS_H
+#if defined(HAVE_WINDOWS_H)
 
 #include <windows.h>
-#define WLOCK(lock)  AcquireSRWLockExclusive(lock);
-#define UNLOCK(lock) ReleaseSRWLockExclusive(lock);
+#define WLOCK(lock)  EnterCriticalSection(lock);
+#define UNLOCK(lock) LeaveCriticalSection(lock);
 
 #else /* HAVE_WINDOWS_H */
 
diff -urEb dcmtk-3.6.9.orig/oficonv/libsrc/citrus_mapper.c dcmtk-3.6.9/oficonv/libsrc/citrus_mapper.c
--- dcmtk-3.6.9.orig/oficonv/libsrc/citrus_mapper.c	2025-02-18 18:03:13.516405780 +0100
+++ dcmtk-3.6.9/oficonv/libsrc/citrus_mapper.c	2025-02-18 18:06:53.928278582 +0100
@@ -64,7 +64,8 @@
 
 #ifdef WITH_THREADS
 #ifdef HAVE_WINDOWS_H
-static SRWLOCK cm_lock = SRWLOCK_INIT;
+static int cm_lock_initialized = 0;
+static CRITICAL_SECTION cm_lock;
 #elif defined(HAVE_PTHREAD_H)
 static pthread_rwlock_t cm_lock = PTHREAD_RWLOCK_INITIALIZER;
 #endif
@@ -355,6 +356,13 @@
     const char *module, *variable;
     int hashval, ret;
 
+#if defined(WITH_THREADS) && defined(HAVE_WINDOWS_H)
+    if (cm_lock_initialized == 0) { /* Very minor risk of race condition here */
+      InitializeCriticalSection(&cm_lock);
+      cm_lock_initialized = 1;
+    }
+#endif
+
     variable = NULL;
 
     WLOCK(&cm_lock);
diff -urEb dcmtk-3.6.9.orig/oflog/include/dcmtk/oflog/thread/syncpub.h dcmtk-3.6.9/oflog/include/dcmtk/oflog/thread/syncpub.h
--- dcmtk-3.6.9.orig/oflog/include/dcmtk/oflog/thread/syncpub.h	2025-02-18 18:03:13.473406452 +0100
+++ dcmtk-3.6.9/oflog/include/dcmtk/oflog/thread/syncpub.h	2025-02-18 18:06:53.928278582 +0100
@@ -63,7 +63,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 Mutex::Mutex (Mutex::Type t)
-    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::Mutex (t) + 0))
+    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::Mutex (t)))
 { }
 
 
@@ -106,7 +106,7 @@
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 Semaphore::Semaphore (unsigned DCMTK_LOG4CPLUS_THREADED (max),
     unsigned DCMTK_LOG4CPLUS_THREADED (initial))
-    : sem (DCMTK_LOG4CPLUS_THREADED (new impl::Semaphore (max, initial) + 0))
+    : sem (DCMTK_LOG4CPLUS_THREADED (new impl::Semaphore (max, initial)))
 { }
 
 
@@ -190,7 +190,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 ManualResetEvent::ManualResetEvent (bool DCMTK_LOG4CPLUS_THREADED (sig))
-    : ev (DCMTK_LOG4CPLUS_THREADED (new impl::ManualResetEvent (sig) + 0))
+    : ev (DCMTK_LOG4CPLUS_THREADED (new impl::ManualResetEvent (sig)))
 { }
 
 
@@ -252,7 +252,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 SharedMutex::SharedMutex ()
-    : sm (DCMTK_LOG4CPLUS_THREADED (new impl::SharedMutex + 0))
+    : sm (DCMTK_LOG4CPLUS_THREADED (new impl::SharedMutex))
 { }
 
 
diff -urEb dcmtk-3.6.9.orig/oflog/libsrc/oflog.cc dcmtk-3.6.9/oflog/libsrc/oflog.cc
--- dcmtk-3.6.9.orig/oflog/libsrc/oflog.cc	2025-02-18 18:03:13.475406421 +0100
+++ dcmtk-3.6.9/oflog/libsrc/oflog.cc	2025-02-18 18:06:53.928278582 +0100
@@ -19,6 +19,11 @@
  *
  */
 
+
+#if defined(_WIN32)
+#  include <winsock2.h>
+#endif
+
 #include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */
 #include "dcmtk/oflog/oflog.h"
 
diff -urEb dcmtk-3.6.9.orig/ofstd/include/dcmtk/ofstd/offile.h dcmtk-3.6.9/ofstd/include/dcmtk/ofstd/offile.h
--- dcmtk-3.6.9.orig/ofstd/include/dcmtk/ofstd/offile.h	2025-02-18 18:03:13.523405671 +0100
+++ dcmtk-3.6.9/ofstd/include/dcmtk/ofstd/offile.h	2025-02-18 18:06:53.929278570 +0100
@@ -569,7 +569,7 @@
    */
   void setlinebuf()
   {
-#if defined(_WIN32) || defined(__hpux)
+#if defined(_WIN32) || defined(__hpux) || defined(__LSB_VERSION__)
     this->setvbuf(NULL, _IOLBF, 0);
 #else
     :: setlinebuf(file_);
diff -urEb dcmtk-3.6.9.orig/ofstd/libsrc/ofstub.cc dcmtk-3.6.9/ofstd/libsrc/ofstub.cc
--- dcmtk-3.6.9.orig/ofstd/libsrc/ofstub.cc	2025-02-18 18:03:13.523405671 +0100
+++ dcmtk-3.6.9/ofstd/libsrc/ofstub.cc	2025-02-18 18:06:53.929278570 +0100
@@ -35,6 +35,10 @@
 #include <windows.h>
 #endif /* HAVE_WINDOWS_H */
 
+#if defined(__LSB_VERSION__)
+#include <errno.h>
+#endif
+
 #define EXITCODE_CANNOT_DETERMINE_DIR        90
 #define EXITCODE_EXEC_FAILED                 91
 #define EXITCODE_ILLEGAL_PARAMS              92