diff --git a/environment.yml b/environment.yml
index 262deb9..9d0c6f1 100644
--- a/environment.yml
+++ b/environment.yml
@@ -3,177 +3,23 @@ channels:
   - pytorch
   - nvidia
   - conda-forge
-  - defaults
+  - nodefaults
 dependencies:
-  - _libgcc_mutex=0.1
-  - _openmp_mutex=5.1
-  - anyio=3.6.2
-  - blas=1.0
-  - brotli=1.0.9
-  - brotli-bin=1.0.9
-  - brotlipy=0.7.0
-  - bzip2=1.0.8
-  - c-ares=1.19.0
-  - ca-certificates=2023.08.22
-  - certifi=2023.7.22
-  - cffi=1.15.1
-  - charset-normalizer=2.0.4
-  - click=8.0.4
-  - coloredlogs=15.0.1
-  - contourpy=1.0.5
-  - cryptography=39.0.1
-  - cuda-cudart=11.8.89
-  - cuda-cupti=11.8.87
-  - cuda-libraries=11.8.0
-  - cuda-nvrtc=11.8.89
-  - cuda-nvtx=11.8.86
-  - cuda-runtime=11.8.0
-  - cudatoolkit=11.8.0
-  - cudnn=8.9.2.26
-  - cycler=0.11.0
-  - dbus=1.13.18
-  - expat=2.4.9
+  - loguru=0.5.3
+  - uvicorn=0.20.0
   - fastapi=0.95.1
-  - ffmpeg=4.3
-  - filelock=3.9.0
-  - flask=2.2.2
-  - fontconfig=2.14.1
-  - fonttools=4.25.0
-  - freetype=2.12.1
-  - giflib=5.2.1
-  - glib=2.69.1
-  - gmp=6.2.1
-  - gmpy2=2.1.2
-  - gnutls=3.6.15
-  - gst-plugins-base=1.14.1
-  - gstreamer=1.14.1
-  - h11=0.12.0
-  - humanfriendly=10.0
-  - icu=58.2
-  - idna=3.4
-  - intel-openmp=2021.4.0
-  - itsdangerous=2.0.1
-  - jinja2=3.1.2
+  - python-multipart=0.0.6
   - janus=1.0.0
-  - jpeg=9e
-  - kiwisolver=1.4.4
-  - krb5=1.19.4
-  - lame=3.100
-  - lcms2=2.12
-  - ld_impl_linux-64=2.38
-  - lerc=3.0
-  - libbrotlicommon=1.0.9
-  - libbrotlidec=1.0.9
-  - libbrotlienc=1.0.9
-  - libclang=14.0.6
-  - libclang13=14.0.6
-  - libcublas=11.11.3.6
-  - libcufft=10.9.0.58
-  - libcufile=1.6.1.9
-  - libcurand=10.3.2.106
-  - libcurl=7.88.1
-  - libcusolver=11.4.1.48
-  - libcusparse=11.7.5.86
-  - libdeflate=1.17
-  - libedit=3.1.20221030
-  - libev=4.33
-  - libevent=2.1.12
-  - libffi=3.4.2
-  - libgcc-ng=11.2.0
-  - libgomp=11.2.0
-  - libiconv=1.16
-  - libidn2=2.3.2
-  - libllvm14=14.0.6
-  - libnghttp2=1.46.0
-  - libnpp=11.8.0.86
-  - libnvjpeg=11.9.0.86
-  - libpng=1.6.39
-  - libpq=12.9
-  - libprotobuf=3.20.3
-  - libssh2=1.10.0
-  - libstdcxx-ng=11.2.0
-  - libtasn1=4.19.0
-  - libtiff=4.5.0
-  - libunistring=0.9.10
-  - libuuid=1.41.5
-  - libwebp=1.2.4
-  - libwebp-base=1.2.4
-  - libxcb=1.15
-  - libxkbcommon=1.0.1
-  - libxml2=2.10.3
-  - libxslt=1.1.37
-  - loguru=0.5.3
-  - lz4-c=1.9.4
-  - markupsafe=2.1.1
-  - matplotlib=3.7.1
-  - matplotlib-base=3.7.1
-  - mkl=2021.4.0
-  - mkl-service=2.4.0
-  - mkl_fft=1.3.1
-  - mkl_random=1.2.2
-  - mpc=1.1.0
-  - mpfr=4.0.2
-  - munkres=1.1.4
-  - ncurses=6.4
-  - nettle=3.7.3
-  - networkx=2.8.4
-  - nspr=4.33
-  - nss=3.74
   - numpy=1.23.5
-  - numpy-base=1.23.5
-  - onnx=1.13.0
-  - onnxruntime=1.12.1
-  - openh264=2.1.1
-  - openssl=1.1.1w
   - pandas=2.1.4
-  - packaging=23.0
-  - pcre=8.45
-  - pillow=9.4.0
-  - pip=23.0.1
-  - ply=3.11
-  - protobuf=3.20.3
-  - pycparser=2.21
-  - pydantic=1.10.2
-  - pyopenssl=23.0.0
-  - pyparsing=3.0.9
-  - pyqt=5.15.7
-  - pysocks=1.7.1
-  - python=3.10.11
-  - python-dateutil=2.8.2
-  - python-flatbuffers=2.0
-  - python-multipart=0.0.6
   - pytorch=2.0.0
   - pytorch-cuda=11.8
-  - pytorch-mutex=1.0
-  - qt-main=5.15.2
-  - qt-webengine=5.15.9
-  - qtwebkit=5.212
-  - re2=2022.04.01
-  - readline=8.2
-  - requests=2.28.1
-  - setuptools=66.0.0
-  - sip=6.6.2
-  - six=1.16.0
-  - sniffio=1.3.0
-  - sqlite=3.41.2
-  - starlette=0.26.1
-  - sympy=1.11.1
-  - tk=8.6.12
-  - toml=0.10.2
-  - torchaudio=2.0.0
-  - torchtriton=2.0.0
+  - mkl=2021.4.0
   - torchvision=0.15.0
-  - tornado=6.2
-  - typing-extensions=4.5.0
-  - typing_extensions=4.5.0
-  - tzdata=2023c
-  - urllib3=1.26.15
-  - uvicorn=0.20.0
-  - werkzeug=2.2.3
-  - wheel=0.38.4
-  - xz=5.2.10
-  - zlib=1.2.13
-  - zstd=1.5.5
+  - onnx=1.13.0
+  - onnxruntime=1.12.1
+  - matplotlib=3.7.1
+  - pip=23.0.1
   - pip:
       - mpmath==1.2.1
       - opencv-python==4.7.0.72
diff --git a/sam_service/sam_queue.py b/sam_service/sam_queue.py
index 5a8e653..0425376 100644
--- a/sam_service/sam_queue.py
+++ b/sam_service/sam_queue.py
@@ -83,6 +83,14 @@ def worker_loop(worker_id:int, work_queue:janus.SyncQueue[WorkItem]):
 counter_lock = Lock()
 counter = 0
 
+async def get_request_id():
+    global counter
+    request_id = None
+    async with counter_lock:
+        request_id = counter
+        counter += 1
+    return request_id
+
 # Start a worker thread for each GPU
 worker_ids = gpus or [0]
 logger.info(f"Creating {len(worker_ids)} workers backed by {gpu_count} GPUs")
@@ -106,8 +114,56 @@ async def docs_redirect():
 
 @app.get("/new_session_id", response_class=PlainTextResponse)
 async def new_session_id():
-    # uuid1 creates time-based identifiers which guarantee uniqueness
-    return uuid.uuid1()
+    """ Create a new session identifier that can be used to identify your client 
+        in other endpoints. 
+    """
+    # uuid4 creates random identifiers which are harder to spoof 
+    # than a counter, and easier to distinguish in the logs
+    return uuid.uuid4()
+
+
+async def cancel_pending_work_items(request_id, session_id):
+    """ Cancel all pending work items for the given session.
+    """
+    for item in session_dict[session_id]:
+        logger.debug(f"R{request_id} - Marking {item} as cancelled")
+        item.cancelled = True
+        # Send notification to waiting request
+        await item.result_queue.async_q.put(None)
+
+
+async def get_embedding(img, request_id, session_id):
+    """ Asynchronously returns the embedding for the given image. 
+        This function creates a work item that is executed on a GPU by a worker thread.
+        It also handles registering the work item in a global dictionary so that a 
+        session's queued items can be invalidated at any time.
+    """
+    # This result queue is used to communicate the result from the worker thread 
+    # back to this function. We only expect one item to be put on this queue.
+    result_queue = janus.Queue()
+
+    work_item = WorkItem(request_id=request_id,
+                         session_id=session_id,
+                         work_function=lambda sam: sam.get_box_model(img), 
+                         result_queue=result_queue)
+    
+    if session_id:
+        logger.trace(f"R{request_id} - Adding {work_item} to session dict")
+        session_dict[session_id].append(work_item)
+
+    logger.trace(f"R{request_id} - Putting work function on the work queue")
+    await work_queue.async_q.put(work_item)
+
+    try:
+        logger.debug(f"R{request_id} - Waiting for embedding to be completed by worker ...")
+        return await result_queue.async_q.get()
+    finally:
+        if session_id:
+            logger.trace(f"R{request_id} - Removing {work_item} from session dict")
+            session_dict[session_id].remove(work_item)
+            # Remove the session if there are no items left, to avoid memory leaks
+            if len(session_dict[session_id])==0:
+                del session_dict[session_id]
 
 
 @app.post("/embedded_model", response_class=PlainTextResponse)
@@ -117,65 +173,31 @@ async def embedded_model(
     cancel_pending: Optional[bool] = Form(False, description="Cancel any pending requests for this session before processing this one"),
     encoding: str = Query("none", description="compress: Response compressed with gzip"),
 ):
-    """Accepts an input image and returns a segment_anything box model
+    """ Accepts an input image and returns a segment_anything box model.
+        Optionally also cancel any pending requests from the same session. 
     """
-    global counter
-    request_id = None
-    async with counter_lock:
-        request_id = counter
-        counter += 1
-        # Python can handle much larger ints but I can't
-        if counter==2**32: counter = 0
-
+    request_id = await get_request_id()
     logger.debug(f"R{request_id} - Started embedded_model for {session_id}")
 
-    # Cancel previous requests if necessary
     if session_id and cancel_pending:
-        for item in session_dict[session_id]:
-            logger.debug(f"R{request_id} - Marking {item} as cancelled")
-            item.cancelled = True
-            # Send notification to waiting request
-            await item.result_queue.async_q.put(None)
+        await cancel_pending_work_items(request_id, session_id)
 
     logger.trace(f"R{request_id} - Reading image")
     file_data = await image.read()
     img = utils.buffer_to_image(file_data)
 
-    def do_work(sam):
-        return sam.get_box_model(img)
-
-    result_queue = janus.Queue()
-    work_item = WorkItem(request_id=request_id,
-                         session_id=session_id,
-                         work_function=do_work, 
-                         result_queue=result_queue)
-    
-    if session_id:
-        logger.trace(f"R{request_id} - Adding {work_item} to session dict")
-        session_dict[session_id].append(work_item)
-
-    logger.trace(f"R{request_id} - Putting work function on the work queue")
-    await work_queue.async_q.put(work_item)
-
-    logger.debug(f"R{request_id} - Waiting for embedding to be completed by worker ...")
-    box_model = await result_queue.async_q.get()
-
-    if session_id:
-        logger.trace(f"R{request_id} - Removing {work_item} from session dict")
-        session_dict[session_id].remove(work_item)
-
-    headers = {}
-    if work_item.cancelled:
-        headers["Cancelled-By-Client"] = "1"
+    embedding = await get_embedding(img, request_id, session_id)
 
-    if box_model is None:
+    if embedding is None:
         logger.debug(f"R{request_id} - Returning code 499 Client Closed Request")
-        return Response(status_code=499, headers=headers)
+        return Response(status_code=499, headers={
+            "Cancelled-By-Client": "1"
+        })
 
     logger.trace(f"R{request_id} - Computed embedding")
 
-    # Serialize the model as base64 string
-    arr_bytes = box_model.tobytes()
+    # Serialize the embedding as base64 string
+    arr_bytes = embedding.tobytes()
     b64_bytes = base64.b64encode(arr_bytes)
     b64_string = b64_bytes.decode('utf-8')
 
@@ -187,21 +209,18 @@ def do_work(sam):
     logger.trace('Compressing embedding ...')
     compressed_data = gzip.compress(b64_bytes)
     logger.debug(f"R{request_id} - Returning compressed embedding")
-    headers["Content-Type"] = "application/gzip"
-    headers["Content-Encoding"] = "gzip"
-    return Response(content=compressed_data, headers=headers)
+    return Response(content=compressed_data, headers={
+        "Content-Type": "application/gzip",
+        "Content-Encoding": "gzip"
+    })
 
 
 @app.post("/cancel_pending", response_class=PlainTextResponse)
 async def cancel_pending(
-    session_id: Optional[str] = Form(None, description="UUID identifying a session")
+    session_id: str = Form(..., description="UUID identifying a session")
 ):
     """Cancel any pending requests for the given session. 
     """
-    # Cancel previous requests if necessary
-    if session_id:
-        for item in session_dict[session_id]:
-            logger.debug(f"Marking {item} as cancelled")
-            item.cancelled = True
-            # Send notification to waiting request
-            await item.result_queue.async_q.put(None)
+    request_id = await get_request_id()
+    await cancel_pending_work_items(request_id, session_id)
+