What is GTV and CTV?
The first of these two volumes is the position and extent of the primary tumour; this is known as the gross tumour volume (GTV). The second volume surrounds the GTV and describes the extent of microscopic, un-imageable tumour spread; this is known as the clinical target volume (CTV).
What is systematic error in radiotherapy?
Random inter-fraction errors are deviations between different fractions and systematic errors are deviations between the planned patient position and the average patient position over the entire course of the treatment.
What is Dmean in radiotherapy?
The association between mean dose (Dmean), maximum dose (Dmax), VX (% SCM volume that received more than X Gy), DX (dose to X% of the SCM volume) at X values of 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 and SCM atrophy at 3 years after IMRT were analyzed.
What are margins in radiotherapy?
The margins, in their simplest form, are simply expansions to the shape of a treatment beam, to ensure that dosimetric planning criteria are met in the presence of inter- and intra-fraction setup variations.
What is PTV and GTV?
In radiation oncology the target volume is that part of the body where a therapeutic dose of irradiation should be applied. This target volume is subdivided into several subsets: the gross tumour target volume (GTV), the clinical target volume (CTV) and the planning target volume (PTV).
What does the GTV include?
The GTV includes all areas of gross disease, including clinically involved lymph nodes. The CTV accounts for microscopic extension. Rigorous pathologic evaluation of surgically resected lung specimens has shown that a margin of 6 to 8 mm can account for 95% of microscopic extension.
What are systematic errors and random errors?
Random error introduces variability between different measurements of the same thing, while systematic error skews your measurement away from the true value in a specific direction.
Can random errors be corrected?
It is predictable. Random errors cannot be eliminated from an experiment, but most systematic errors can be reduced.
What wavelength is used in radiation therapy?
Supervoltage X-rays – 500 to 1000 keV.
What are the side effects of radiotherapy?
Ask your care team about the side effects you might get.
- Sore skin. In some people, radiotherapy can make the skin sore and red (similar to sunburn), darker than normal or dry and itchy.
- Tiredness.
- Hair loss.
- Feeling sick.
- Problems eating and drinking.
- Diarrhoea.
- Stiff joints and muscles.
- Sex and fertility issues.
How is PTV calculated?
Patients and methods The van Hark formula (PTV margin =2.5Σ +0.7σ) was applied to calculate PTV margins of prostate/seminal vesicles (P/PSV) using CBCT or FM.
What is the GTV?
The gross tumor volume (GTV) is defined as the gross palpable or visible/demonstrable extent and location of malignant growth.
Are there feasible measurement errors in in vivo dosimetry during radiottherapy?
Feasible measurement errors when undertaking in vivo dosimetry during external beam radiottherapy of the breast. Med Dosim 2003 Spring;28 (1):45-8. The Pennsylvania Patient Safety Advisory may be reprinted and distributed without restriction, provided it is printed or distributed in its entirety and without alteration.
How do human errors affect the final result of radiation treatment?
Leunens G, Verstraete J, Van den Bogaert W, et al. Human errors in data transfer during preparation and delivery of radiation treatment affecting the final result: “garbage in, garbage out.” Radiother Oncol 1992 Apr;23 (4):217-22. Fraass BA. QA issues for computer-controlled treatment delivery: this is not your old R/V system anymore!
What are the most common errors in external beam radiation therapy?
This article focuses on types of external beam radiation therapy events reported in Pennsylvania and in the literature related to external beam radiation therapy. The most common errors reported include patients receiving the wrong dose of radiation, the wrong site being treated, and the wrong patient being treated.
How are radiation therapy errors reported in the state of Pennsylvania?
In the Commonwealth of Pennsylvania, events related to errors in the administration of radiation therapy are reported to two statutory bodies: the Pennsylvania Patient Safety Authority and the Pennsylvania DEP. It was noted in review of both data sets that the overall number of reports is low.