Comparisons with Competing Technologies
Dosimetric measurements are performed daily in radiotherapy to ensure the proper radiation dosage is being delivered precisely and accurately. Currently, this task is accomplished by the following four technologies: ionization chambers, thermoluminescence dosimeters (TLDs), film dosimeters, and semiconducting dosimeters. Although these devices have their own inherit advantages, several disadvantages exist highlighting the need for a new generation of radiation dosimeters .The following table summarizes the current technologies:
Radiation Dosimeter |
Advantage |
Disadvantage |
Ionization Chamber |
- Accurate absorbed dose measurement, current gold standard.
|
- Requires high bias voltage (> 300V), increasing potential damage to patient and limiting portability of device.
- Large physical size with low spatial resolution
- Are not used for in vivo dosimetry.
|
TLD |
- Available in a wide range of materials, sizes and shapes.
- Easy to use.
|
- Sensitive to environmental conditions, handling procedures and heating conditions.
- Repeated use diminishes accuracy.
- Post radiation dose readout, TLD can no longer be used.
- Real-time and dose rate measurements not possible.
|
Film Dosimeter |
- 2 dimensional radiation beam profile.
- Portable
|
- Qualitative radiation measurement, rather than quantitative.
- Non-linear response to radiation dosage.
- Film is ultraviolet light sensitive
|
Semiconducting Dosimeter |
- Small physical size.
- Portable and can be placed on or within a patient.
- Provide real-time feedback
|
- Non-linear radiation dose response.
- Temperature and environmental dependent.
- Limited life span
|