Hi again Lauren0125-ga, and thanks for your question.
As I mentioned, probably the most data on this topic has been
accumulated from experience in the treatment of tumors via
hyperthermia. Hyperthermia uses focused ultrasound, radio-frequency,
or microwaves to raise the temperature of tissues (or organs) while
sparing the skin. Hyperthermia is typically performed by a radiation
oncologist, often in conjunction with radiation therapy. If you'd
like some specific details on hyperthermia itself, I suggest posting a
separate, focused question on this topic.
The Palo Alto Medical Foundation is one of the centers in the US that
administers hyperthermia treatments. They have a patient oriented
site that discusses the basics:
"Discomfort: The most common side effect of hyperthermia treatment is
a sensation of warmth and discomfort during treatment, which can be
managed with pain medications prior to or during hyperthermia if
needed. In addition, there may be some tenderness at the probe
insertion sites for a couple days following treatment."
This site also gives the limiting temperatures for treatment:
"Local or regional hyperthermia treatment most often involves the use
of ultrasound, microwaves or radio-frequency (RF)-induced currents to
raise body temperatures at a specific site. The temperature range
achieved is 41-45 degrees Celsius or 106-113 degrees Fahrenheit,
similar to a hot bath."
Typically, the goal for treatment is 42.5-43 degrees Celsius (108.5 -
109.4 Fahrenheit). Most hyperthermia is aimed at tissues 1-8cm beneath
the skin surface. Deeper treatments are more experimental, but is
becoming more widespread as techniques are developed. I've assisted in
the administration of such deep hyperthermia treatments and know that
pain secondary to heat in the deep tissues is typically the limiting
factor. Another concern is causing fat necrosis, but this typically
occurs at a higher temperature and longer duration of treatment than
one can usually tolerate due to pain.
Obviously, different organs have different pain sensitivities. For
example (ironically), the brain has no pain sensing neurons, while the
Here's the NIH page on hyperthermia, with more details:
The American Cancer Society hyperthermia page:
Here are some references for the above:
van der Zee J. Heating the patient: a promising approach?. [Review]
[114 refs] [Journal Article. Review] Annals of Oncology.
13(8):1173-84, 2002 Aug.
The free full text is available here:
Dick EA. Taylor-Robinson SD. Thomas HC. Gedroyc WM. Ablative therapy
for liver tumours. [Review] [54 refs] [Journal Article. Review.
Review, Tutorial] Gut. 50(5):733-9, 2002 May.
The free full text is here:
Goldberg SN. Gazelle GS. Mueller PR. Thermal ablation therapy for
focal malignancy: a unified approach to underlying principles,
techniques, and diagnostic imaging guidance.[see comment]. [Review]
[67 refs] [Journal Article. Review. Review, Tutorial] AJR. American
Journal of Roentgenology. 174(2):323-31, 2000 Feb.
Free full text is here:
hyperthermia "radiation oncology" organs pain
I hope this information was useful. Please feel free to request any clarification.