A medical instrument (700, 800) comprising: - a first display device; - a second display device; - a database; - a memory for storing machine executable instructions (780, 782, 784, 786); - a processor for execution the machine executable instructions, wherein execution of the instructions cause the processor to: - receive a medical image (102, 102', 102", 102"'); - display the medical image in a physician graphical user (202, 1000) interface using the first display device; - display the medical image on a technician graphical user interface (100, 1000) using the second display device; wherein execution of the instructions causes the processor to repeatedly: - receive planning data from the physician graphical user interface, wherein the planning data is descriptive of a location in the medical image; - display the planning data on the technician graphical user interface; - receive treatment plan data from the technician graphical user interface; - store the treatment plan data in the database; - generate control data (770, 772) for controlling a treatment system using the treatment plan data in the database characterised in that the execution of the instructions further cause the processor to - divide at least a portion of the medical image into treatment cells (604, 1008), wherein the database stores the control data for each of the treatment cells; - receive a selection of a first treatment cell using the treatment plan data; - lock the control data of the first treatment cell in the database to restrict modification of the control data of the first treatment cell to only the treatment plan data; - modify the control data of the first treatment cell using the treatment plan data; - unlock the cell control data of the first treatment cell in the database after modification with the cell control data; - receive selection of a second treatment cell using the planning data; - lock the cell control data of the second treatment cell in the database to limit modification of the cell control data of the second treatment cell by the planning data; - modify the cell control data of the second treatment cell using the planning data; and - unlock the cell control of the second chosen treatment cell data in the database after modification with the cell control data. - a first display device; - a second display device; - a database; - a memory for storing machine executable instructions (780, 782, 784, 786); - a processor for execution the machine executable instructions, wherein execution of the instructions cause the processor to: - receive a medical image (102, 102', 102", 102"'); - display the medical image in a physician graphical user (202, 1000) interface using the first display device; - display the medical image on a technician graphical user interface (100, 1000) using the second display device; wherein execution of the instructions causes the processor to repeatedly: - receive planning data from the physician graphical user interface, wherein the planning data is descriptive of a location in the medical image; - display the planning data on the technician graphical user interface; - receive treatment plan data from the technician graphical user interface; - store the treatment plan data in the database; - generate control data (770, 772) for controlling a treatment system using the treatment plan data in the database characterised in that the execution of the instructions further cause the processor to - receive a medical image (102, 102', 102", 102"'); - display the medical image in a physician graphical user (202, 1000) interface using the first display device; - display the medical image on a technician graphical user interface (100, 1000) using the second display device; - receive planning data from the physician graphical user interface, wherein the planning data is descriptive of a location in the medical image; - display the planning data on the technician graphical user interface; - receive treatment plan data from the technician graphical user interface; - store the treatment plan data in the database; - generate control data (770, 772) for controlling a treatment system using the treatment plan data in the database characterised in that the execution of the instructions further cause the processor to - divide at least a portion of the medical image into treatment cells (604, 1008), wherein the database stores the control data for each of the treatment cells; - receive a selection of a first treatment cell using the treatment plan data; - lock the control data of the first treatment cell in the database to restrict modification of the control data of the first treatment cell to only the treatment plan data; - modify the control data of the first treatment cell using the treatment plan data; - unlock the cell control data of the first treatment cell in the database after modification with the cell control data; - receive selection of a second treatment cell using the planning data; - lock the cell control data of the second treatment cell in the database to limit modification of the cell control data of the second treatment cell by the planning data; - modify the cell control data of the second treatment cell using the planning data; and - unlock the cell control of the second chosen treatment cell data in the database after modification with the cell control data.